[HOME],
[START]
BioFinder Kategorien Suche
Entwicklung < Biologie
Weitere Unterkategorien:
Links in dieser Kategorie:
-
Project The fission yeast Schizosaccharomyces pombe is a unicellular ascomycete. It has a simple eukaryotic genome of approximately equivalent size to that of budding yeast, Saccharomyces cerevisiae, at around 14 Mb. Unlike S. cerevisiae, the S. pombe genome is spread between only three chromosomes. The S. pombe sequencing project was initiated at the Sanger Centre as a pilot project in 1995. Further funding was secured from the European Commission in 1996 to allow a consortium of European Sequencing Laboratories to continue the project.
-
THE IMMORTAL LIFE CYCLE OF TURRITOPSIS NUTRICULA
The hydrozoanTurritopsis nutricula has evolved a life cycle that may have achieved immortality. The solitary medusa (jellyfish) of this species can revert to its polyp stage after becoming sexually mature. After spawning, it becomes a juvenile again. To do so, cells have to differentiate into other types of cells.
-
UPDATE ON SEGMENTATION GENES IN DROSPHILA.
Several surprising results indicate that the regulation of pair-rule genes may be more complex than we had thought and that the segment-polarity gene expression in the developing head differs from its expression in the rest of the body.
- A 3-D Digital Anatomical Atlas and Database of Gene
Genetic information is expressed in complex and ever-changing patterns throughout the development of the mammalian embryo. A description of these patterns and how they relate to the emerging tissue structure of the embryo is crucial for our understanding of the network of genetic interactions that underlie the processes of normal development, disease and evolution. Studies of gene expression are rapidly producing a very large amount of information relating to these complex patterns. This creates serious difficulties in publishing, scanning and accessing the information. It also creates difficulties in making comparisons between the expression of different genes in order to assess the possibility of complex networks of genetic interaction. These problems cannot be addressed by conventional means of publication, but will require the development of a widely accessible, electronic database. Moreover, text descriptions of gene expression are often of limited value partly as a consequence of the spatial complexity of the patterns and partly because domains of gene expression do not necessarily correspond to named anatomical structures.
- A high throughput screen to identify novel secreted and transmembrane proteins i
Secreted and transmembrane proteins play an essential role in intercellular communication during the development of multicellular organisms. As only a small number of these genes have been characterized, we developed a screen for genes encoding extracellular proteins that are differentially expressed during Drosophila embryogenesis. Our approach utilizes a new method for screening large numbers of cDNAs by whole embryo in situ hybridization. The cDNA library for the screen was prepared from rough endoplasmic reticulum-bound mRNA, and is therefore enriched in clones encoding membrane and secreted proteins. To increase the prevalence of rare cDNAs in the library, the library was normalized using a novel method based on cDNA hybridization to genomic DNA-coated beads. In total, 2518 individual cDNAs from the normalized library were screened by in situ hybridization, and 917 of these cDNAs represent genes differentially expressed during embryonic development. Sequence analysis of 1001 cDNAs indicated that 811 represent genes not previously described in Drosophila. Expression pattern photographs and partial DNA sequences have been assembled in a database publicly available at the Berkeley Drosophila Genome Project website (http://www.fruitfly.org). The identification of a large number of genes encoding proteins involved in cell-cell contact and signaling will advance our knowledge of the mechanisms by which multicellular organisms and their specialized organs develop.
- abdominal-A
As recently as 1986, models of the bithorax complex of genes posited not three genes, (abdominal A, Abdominal B and Ultrabithorax) as is currently assumed, but seven or eight, each independently regulated and controlled by the repressor Polycomb. This earlier model of development suggested that the cuticular phenotype of each segment depended on an array of up to eight BX-C substances elaborated in each segment. Only with the cloning of the bithorax complex genes (Regulski, 1985) was the picture more accurately understood. It then became clear that only three genes, not eight, were responsible for all the phenotypes observed.
- Abdominal-B
Pair-rule and segment polarity genes are responsible for determining the uniformity of different segments, in contrast to homeodomain proteins that are responsible for establishing the diversity between segments. Abdominal-B acts in three germ cell layers to fulfill this latter function. Abdominal-B is the last in linkage order and the most posterior acting of the linked homeodomain proteins of the bithorax. Abdominal-B is unique among the homeotics in that it is transcribed in two forms; a regulatory (r) protein and a morphogenic (m) protein. Regulatory transcripts of Abdominal-B act as repressors, suppressing embryonic ventral epidermal structures in the 8th and 9th segments of the abdomen. Thus ABD-B r and m proteins are critically involved in establishing cell fate in the tail segments of the fly.
- Abl oncogene
The Philadelphia chromosomal translocation is responsible for the fusion of two genes, ABL and BCR. Recognized as a frequently occuring aberrant chromosome in acute lymphoblastic leukemia, it was understood more than a decade ago that the Philadelphia chromosome occurs as a result of a recombination between two genes: the cellular ABL gene on chromosome 9, and BCR (breakpoint cluster region) gene located on chromosome 22. The Drosophila Abelson (Abl) protein is a homolog of mammalian c-Abl the wild-type gene coding for the ABL sequence found in the BRC/ABL hybrid protein. The BCR/ABL oncogene product, derived from this specific chromosomal translocation is present in Philadelphia chromosome-postive acute lymphoblastic leukemia. Despite its homology to c-Abl, the wild type mammalian protein, Drosophila ABL protein shows distinct properties and functional differences from c-Abl that suggest the two proteins are not strictly comparable.
- About Mouse Genome Informatics (MGI)
The Mouse Genome Informatics (MGI) Web site provides integrated access to various sources for information on the genetics and biology of the laboratory mouse. The MGI resource comprises the Mouse Genome Database (MGD), the Gene Expression Database (GXD) and the Encyclopedia of the Mouse Genome (Encyclopedia).In addition .MGI provides access to related resources including the Mouse Tumor Biology database and the Rat Data resource.
- AMS Analytical micro Analytical micro-Systems: devices and chemicals for bioanalytics, material scien
Analytical micro-Systems (Regensburg, Germany) We offer devices and chemicals for bioanalytics, material science, biophysics: SPR spectrometer, impedance analyzer, functionalized alkylthiols; coating of gold electrodes by stable organic compounds for further immobilization of biomolecules
- Anatomy of the 24, 48, 72 and 120 hours Zebrafish (Danio rerio) Embryo
This collection of sections through zebrafish embryos at four different stages of development is thought to provide some help to understand how the zebrafish embryo looks inside. Thin section in Araldite were stained with methylene blue. Images were taken and digitized. You will find an overview image for each stage, with links (click at numbers on image) to images of the sections. You can also download high resolution images (JPEG, about 1 MB), which in most cases are good enough to zoom in down to the level of individual cell nuclei.
- ANGIOSPERM DEVELOPMENT.
For those of you craving a plant chapter, here is a great one It is a chapter written by Dr. Susan Singer for the textbook Embryology: Constructing the Organism (Sinauer Associates, Sunderland, 1997). The author and publisher have generously given permission for anyone to download and copy this chapeter for classroom use. One version is a pdf Acrobat file which is designed for copying.
- BDGP Publications and Laboratory Methods
BDGP Publications and Laboratory Methods
- CALCIUM RELEASE DURING ECHINODERM FERTILIZATION IS MEDIATED BY PHOSPHOLIPASE
CALCIUM RELEASE DURING ECHINODERM FERTILIZATION IS MEDIATED BY PHOSPHOLIPASE Cg.
- Caulobacter crescentus overview
Caulobacter crescentus is one of the best understood examples of an organism that posesses true intrinsic asymmetry. Every cell division gives rise to two different cell types, a motile, flagellum-bearing swarmer cell and a sessile stalked cell. These two cell types differ not only in motility, but also in the complement of genes that they express and in their capacity to reinitiate chromosomal DNA replication. Asymmetry is generated in the predivisional cell through the differential targeting of flagellar and chemotaxis proteins, and through compartment-specific gene regulation.
- CBFA-1: TURNING MESENCHYME INTO BONES
While the MyoD family of transcription factors can transform mesenchyme into myoblasts, the CBFA-1 transcription factor appears to be able to transform these cells into osteoblasts, the cells that make the bones. A human skeletal syndrome is caused by heterozygosity at this locus.
- CHROMATIN DIMINUTION IN ASCARIS.
Chromatin diminution in the roundworm Ascarisis not haphazard. Moreover, when chromosome fragments are lost in the somatic lines of Ascaris, certain genes are discarded from those cells.
- CLONING MAMMALS: WHAT DOES IT MEANNULL
This is an update to the website on Dolly, taking into account the report of three cloned bull calves. It is an opinion paper, looking at what cloning can do.
- CONKLIN'S ANALYSIS OF ASCIDIAN SPECIFICATION
In 1905, E. G. Conklin showed that the cytoplasm that formed the yellow crescent gave rise to musculature and that the lineaments of the larvae were present in the cytoplasm as early as the two-cell stage. We've scanned each of Conklin's figures individually and placed them on this site.
- CONNEXIN-37 AS THE CRITICAL GAP JUNCTION PROTEIN BETWEEN GRANULOSA CELLS AND THE
Recent studies show that gap junction protein connexin-37 is present between the granulosa cells of the follicle and the mouse oocyte. In the absence of this protein, junctional coupling is lost between these cells, and the oocytes fail to mature, and ovulation does not occur.
- Das Fischbach Labor
- Department of Craniofacial Development
- Developmental Biology by Scott F. Gilbert
Website supporting the textbook (Lehrbuch) of S.F. Gilbert
- Die Säugerseite (Neurogenetik - Online)
- DIFFERENTIATION THERAPY FOR ACUTE MYELOCYTIC LEUKEMIA.
Acute myelocytic leukemia is characterized by the proliferation of immature white blood cells due to a defective retinoic acid receptor. Large doses of retinoic acid appear to cause these cells to differentiate, thereby inhibiting this cancer.
- DISTAL-LESS: INSTRUCTIONS TO STICK IT OUT
The expression of the Distal-less gene appears to be conserved throughout the bilateral phyla. This protein may signal that a developing structure stick out from the body axis. In many instances, it is expressed in the cells that will become the distal-most region of a developing appendage such as the chicken limb or the echinoderm tubed foot.
- EST - Gene Links
598 previously identified Drosophila Melanogaster genes have been found among the EST libraries. This represents 44.7% of the sequenced Drosophila genes.
- Establishment of the Dorsal nuclear localization gradient
The pattern along the dorsoventral axis of the Drosophila embryo is determined by a nuclear localization gradient of the transcription factor Dorsal. On the ventral side of the embryo Dorsal is present only within the nuclei. It is distributed, however, between the cytoplasm and the nuclei on lateral positions, and restricted to the cytoplasm on the dorsal side. Dorsal regulates the expression of its target genes, for example twist and zerknüllt, in dependence of its nuclear concentration, so that a stripe-like pattern of gene expression domains along the anterior-posterior axis emerges.
- European Drosophila Genome Project (EDGP)
The European Drosophila Genome Project has the objective of sequencing the X chromosome of Drosophila melanogaster. Divisions 1 to 3 (about 3-3.5 Mbases) will be sequenced by the end of the year 1999. Sequencing is based on the cosmid physical map, constructed by the European Drosophila Physical Mapping Project.
- Fertilization and the block to polyspermy
Sperm-egg interactions result in a cascade of molecular responses that include exocytosis of the cortical granules. This secretory event functions in the permanent block to polyspermy that most eggs rely upon for fertilization, and in the formation of a protected environment for early embryonic development. We are examining the contents of the cortical granules to understand their function in the modification of the egg cell surface and extracellular matrix. Our functional characterization includes a molecular analysis of the protease and peroxidase activities, the structural proteins of the fertilization envelope, and the major protein of the extraembryonic matrix, hyalin.
- FGF10 AND THE INITIATION OF THE LIMB BUD
New studies suggest that another fibroblast growth factor, FGF-10, is responsible for inducing the limb to form. It is expressed in the lateral plate mesoderm cells that give rise to the limb bud mesenchyme, and FGF-10 will induce FGF8 expression in the apical ectodermal ridge.
- Fin development
We are studying the development of the pectoral fins of the zebrafish, as they are considered to be homologous to the tetrapod forelimbs. We have carried out a detailed study of the development of the wildtype fins, and are now in the process of analysing mutants that show defects in fin development. Embryos mutant in babyface, sonic you, and dackel either show a reduced or an almost absent pair of pectoral fins. Analysis of double mutants has begun to provide insight into the interaction of particular genes, and experimental studies are under way to elucidate which structures of the fin can be considered homologous in function to their tetrapod counterparts (e.g., is the apical ectodermal fold in fish equivalent to the AER in tetrapodsNULL).
- FML Friedrich-Miescher-Laboratorium der Max-Planck-Gesellschaft
- Fungal Genetics
fungal genetics, vector development for Mucor-like fungi, zygomycetes, evolution, strain collection fungal reference center, lignin degradation, developmental biology of Mucor-like fungi, plant pathology
- GENES FOR CORTICAL LAMINATION
The six-layered structure of the cerebral cortex is ordered by particular proteins that are expressed in glial cells and migrating neuron. Analyses of the human lissencephaly syndromes and mouse knockouts have identified some of these factors.
- GENES FOR HUMAN HAIR PRODUCTION.
Congenital alopecias are conditions where hear is not properly produced. Two human genes involved in hair production have recently been identified and are found to act at different points in the production of human hair. These genes are those whose absence causes anhidrotic ectodermal displasia (lack of hair, teeth, and sweat glands) and alopecia universalis (complete congenital absence of hair).
- Genetic Map of Caulobacter crescentus
The map is depicted in four segments which forms a single continuous linkage group as defined by RP-4 mediated conjugation(4), bacteriophage CR30 mediated transduction (15) and pulsed field gel electrophoresis (11,13). The numbers (in kilobases) indicate the approximate position of selected genes. Parentheses indicate that the precise location of the gene relative to adjacent genes is not known. Preceding * indicates that the relative orientation of the gene cluster is not known. ] after the gene indicates continuous genes.
- Genetic mapping of mutations in the zebrafish
A large number of developmental mutants of the zebrafish have been isolated in a recent mutagenesis screen (Haffter et al., 1996a; Haffter et al., 1996b). Our aim is to place 665 of these mutations on a simple sequence length polymorphism map as a first step towards molecular analysis. For our project we have selected 182 SSLP markers (Knapik, E. W. et al. (1996) Development 123, 451-60; Goff, D. J. et al. (1992) Genomics 14, 200-2) that give strong and easily distinguishable PCR products when amplified from the Tü line, in which the mutagenesis was done, and from the newly established reference line WIK (available from the Tübingen stockcenter).
- Growth Factors and Oncogenes
Although the MRFs positively activate the myogenic program, the activity of these proteins is tightly regulated through a growth factor-mediated signal transduction cascade. MRF-expressing cells maintained in a serum-free medium rapidly differentiate by transcriptionally activating muscle structural genes. Differentiation is inhibited, however, when the serum-free medium is supplemented with purified growth factors such as fibroblast growth factor-2 (FGF-2) or transforming growth factor-b (TGF-b). A similar inhibition of activity also is observed when the muscle regulatory factors are co-expressed in cells containing high levels of several oncogenes such as c-myc, H-ras and c-jun. Understanding how these diverse growth control agents inhibit the MRF proteins from transcriptionally activating various structural genes is a major goal of the Konieczny and Taparowsky laboratories. Current studies are focused on examining how specific phosphorylation events regulate the ability of the MRFs to dimerize with other bHLH proteins, to bind to DNA and to function as transcriptional activators (Mol. Cell Biol., 1995, 15:5205-5213; Mol. Cell Biol., 1996, 16:1604-1613). In addition, we are dissecting the individual pathways by which the G protein Ras functions to repress myogenesis (Mol. Cell Biol., 1997, 17:3547-3555). Recently, we have found that an additional Ras pathway, distinct from the well characterized MAP kinase and Rac/Rho pathways known to be important for the transforming function of activated Ras, is primarily responsible for the inhibition of myogenesis by H-Ras. Understanding the signal transduction pathways that negatively and positively regulate the activity of these novel transcription factors should provide a critical view as to how growth factors and oncogenes control these important developmental decisions.
- HAECKEL'S DRAWING OF VERTEBRATE DEVELOPMENT
Long an icon of embryology and evolutionary biology books, a 100-year-old drawing by E. Haeckel showed that all vertebrate embryos pass through an identical stage. Recent studies suggest this was wishful thinking.
- HOW THE ZEBRA GOT ITS STRIPES
Really, we don't know. However, Jonathan Bard has proposed a model which may explain the striping patterns of the three extant species of zebra.
- How were the cDNA libraries madeNULL
We have produced two new full length cDNA libraries: the GH adult head library and the LP larval and early pupal stage library. Since many of the HL adult head library clones were not full length, and others lacked inserts, we chose to remake this library. We are currently sequencing from these libraries.
- Hyper Neuroblast Map
- Institut für Mikrobiologie/Mikrobengenetik
- Institute of Microbiology / Microbe Genetics - FSU Jena
fungal genetics and evolution, zygomycetes (Absidia, Mucor, Phycomyces, ...), developmental biology, plant pathology, molecular probes for plant and human pathogens, lignin degradation, vector development
- LAWS OF DEVELOPMENTAL GROWTH
The limits to growth are one of the most important constraints on how animals can evolve. The laws of diffusion, hydraulics, and scaling are critical parameters that developing organisms must obey.
- Localization of bicoid mRNA in Drosophila embryos
The anterior pole of the Drosophila embryo is determined already during oogenesis by the localization of the maternal bicoid mRNA which is mainly produced in the nurse cells, transported to the oocyte and localized to the anterior pole. As a result, a bicoid protein gradient with its highest concentrations at the anterior pole is generated through translation from the localized source shortly after fertilization. The protein acts as a transcription factor that activates several target genes, thereby creating a basic differential gene expression pattern which subsequently will be further refined.
- Maternal mutant screen in the zebrafish
The earliest patterning events in vertebrate embryogenesis are still poorly understood. In lower vertebrates, these events are initiated by maternal factors present in the egg (such as involved in bicoid localization in Drosophila). In order to identify genes coding for such factors, we are carrying out a screen for maternal-effect mutations in the zebrafish. Mutations are induced in the germ line of parental (P) males by exposing them to the point-mutagen N-ethyl-N-nitroso-urea (ENU). P males are then mated to produce F1 progeny heterozygous for the induced mutations. Eggs are stripped from the F1 females and gynogenesis is artificially induced using early pressure, which inhibits the second meiotic division of the egg. This allows mutations to become homozygous in the gynogenetic F2 generation. Finally, F2 adult females are screened for maternal-effects by crossing them to wild type males and testing their progeny for embryonic phenotypes.
- Maternal mutants in Drosophila
In Drosophila, large scale mutagenesis screens have revealed genetic components required maternally for the establishment of the embryonic axes. Four groups of genes act in a largely independent manner to specify the antero-posterior and the dorso-ventral axis, as well as the terminal regions of the embryo. In total, about 30 genes whose products are essential for pattern formation during oogenesis have been identified by maternal-effect mutations. Although most of the components involved in axis formation have probably been found by this approach, several genetic and biochemical arguments suggest that certain genes have escaped detection in the classic screens. These screens allowed the isolation of mutations only in genes whose function is strictly maternal: genes which also have an essential function at other developmental stages could not be identified. Also, based on the obtained allele frequencies, the screens did not reach saturation.
- Max-Planck-Institut für Entwicklungsbiologie
- Mechanisms of cell determination in Drosophila
A crucial part of the process of cell determination (the acquisition of specific cell fates during development) is the activation of homeotic genes in some but not all primordia in the early embryo. Homeotic genes act throughout development to control proper patterning of various structures derived from these primordia, and thus the active state of homeotic genes has to be maintained through subsequent cell divisions as the primordia grow. Similarly, in those primordia where particular homeotic gene products are not wanted, these genes must remain inactive.
- Mesoderm and gastrulation
We are interested in the source of mesoderm inducing signals in the early fish blastula and are using experimental embryology to adress this issue. A main focus of the lab is the analysis of mutants which exhibit a dorsalized or ventralized phenotype. We have shown that the dino and swirl mutant phenotypes (Hammerschmidt, 1996a; Mullins, 1996) are caused by mutations in the chordino and the zBMP2 gene respectively (Schulte-Merker et al., 1997; Kishimoto et al., submitted), and are currently analysing these and other mutants. The aim of all these studies is to elucidate which maternal and zygotic factors pattern the early zebrafish embryo.
- Mist1: a Novel bHLH Factor
Previous studies in the lab have confirmed that bHLH factors, such as members of the MyoD family of proteins, play critical roles in regulating both gene transcription and cell fate determination. Our studies also have demonstrated that active and negative strategies are involved in controlling the establishment and maintenance of a particular phenotype. In order to better understand how bHLH proteins interact and regulate each other's activities, we recently utilized a yeast one-hybrid screening strategy to identify an additional member of the complex bHLH protein network, Mist1 (DNA and Cell Biology, 1996, 15:1-8). Mist1 exhibits a complicated expression pattern with transcripts being detected in several different cell derivatives (Dev. Biol., 1997, 182:101-113). In the mesoderm, Mist1 transcripts are expressed in all skeletal muscle forming regions during embryonic days E12.5 and E16.5.
- MLP, a Muscle LIM Protein
A large family of proteins recently has been identified that contains a cysteine-rich structural motif consisting of the sequence (CX2CX16-23HX2C)-X2-(CX2CX16-21CX2C/H/D). This motif is known as a LIM domain due to its presence in three developmentally important transcription factors; Lin-11, Isl-1 and Mec-3. The LIM domain is a zinc-binding structure that coordinates two atoms of zinc in a tetrahedral fashion via the conserved cysteine and histidine residues in the LIM consensus. One such LIM protein, referred to as MLP for muscle LIM protein, is expressed exclusively in skeletal and cardiac muscles, localizes to discrete cell compartments in the nucleus and cytoplasm and has been found to promote muscle differentiation. Overexpression of MLP in C2C12 myoblasts enhances skeletal myogenesis, whereas inhibition of MLP activity blocks terminal differentiation. Thus, MLP functions as a positive developmental regulator, although the mechanism through which MLP promotes terminal differentiation events remains unknown.
- Molecular and cellular biology of the cellular slime mold Dictyostelium
The cellular slime mold Dictyostelium discoideum has a relatively simple and easily studied developmental program which shares many features with those of higher organisms. We use the molecular genetic and cell biological techniques available in this system to explore the key molecular regulatory mechanisms controlling cell-type differentiation and pattern formation.
- MORE PLANT DEFENSES AGAINST CATERPILLAR ATTACKS
When the beet armyworm caterpillar eats corn seedlings, the wounded plant cells use a compound in the caterpillar's saliva to induce the secretion of certain voltile copounds that attract wasps to kill the caterpillar.
- Mutations affecting midline signaling in the zebrafish
Signals from the vertebrate midline have for a long time been implicated in patterning the paraxial mesoderm and the ventral neural tube. In the zebrafish, a number of mutations affecting the midline have been described. Among these are mutations affecting formation of the notochord, mutations affecting somite patterning and mutations affecting the ventral neural tube. Mutations in six genes affect the formation of the horizontal myoseptum, which in the wildtype separates the somites into a ventral and a dorsal part. This class of mutants, termed the you-type mutants, forms U-shaped instead of V-shaped somites. Earlier in development, these mutants are affected in the adaxial cells and the muscle pioneers. The similarity of the somite phenotype in mutants lacking the notochord and in the you-type mutants suggests that the you-type genes are involved in a signaling pathway from the notochord involved in patterning the somites.
- Myosin Light Chains
Dictyostelium as a model for the analysis of myosin light chain mutations that cause familial hypertrophic cardiomyopathy.
- NEMATODE GUT DETERMINATION: THE P2 BLASTOMERE ACTS ON EMS THROUGH THE WNT
Genetic screens for mutants of endoderm formation have found that components of the Wnt signaling pathway enable the EMS cell to form both mesoderm and endoderm.
- NEURAL CREST CELL MIGRATION DIRECTED BY EPH-RELATED RECEPTORS
Migration of neural crest cells may be patterned by interactions between Eph receptors in the membranes of neural crest cells and ephrin ligands in the cells they encounter. Such interactions impede migration, allowing the crest cells to migrate in the regions not expressing the ephrin ligands.
- Neural crest development
The neural crest provides a population of pluripotent, highly migratory cells which delaminate from the neuroepithelium and differentiate into a wide range of cell types. Neural crest cells originate from the mid- and hindbrain and migrate ventrally to populate the developing head. Once they have reached their targets they differentiate into cartilage, connective tissue, sensory neurons and pigment cells. Although neural crest development has been studied for some time by elegant embryological and in vitro studies very little is known about the genes which regulate this process. As neural crest cells are one of the few vertebate cell types which have no clear analogue in invertebrate species, it is more difficult to apply results from genetic screens in Drosophila and C.elegans to this problem. We are currently using mutants isolated in a large scale zebrafish screen to identify and, eventually, molecularly characterise genes involved in neural crest development in vivo.
- NEURAL RESTRICTIVE SILENCER ELEMENT.
Certain sequences prevent the transcription of certain genes in all cells except for a relatively small subset. One of these sequences is the neural restrictive enhancer which prevents the transcription of several genes in any cells but post-mititic neurons and glia.
- Neuroendocrine Control of Insect Development
In insects, as in all animals, development is largely under hormonal control. Based on studies in numerous species conducted over the past 80 years, a general model of insect development has emerged. The two primary insect hormones are the steroid ecdysone (or its derivatives) and the sesquiterpenoid juvenile hormones. Ecdysteroid titers determine the timing of passage from one developmental stage to another, e.g. from one larval instar to the next, and juvenile hormone titers determine the qualitative aspects of that change, e.g. whether larval, pupal, or adult cuticle is laid down by the epidermis.
- Nobel Prize in Physiology or Medicine 1995
Announcement by the Nobel Assembly
- Nüsslein-Volhard Lab (MPI für Entwicklungsbiologie)
- Overview
The human genomic research programme at the Sanger Centre encompasses mapping, sequencing, and structural and functional interpretation. Some groups work on specific chromosomes. Others are devoted to whole genome mapping, developing resources, or automation, data-handling and analysis. Additional groups are involved in discovering ways of analysing sequences, comparisons with other genomes, studying the structure and expression of genes, identifying polymorphisms, and examining chromatin structure in relation to function. These studies will contribute to the annotation of the human genome sequence and ultimately will provide a detailed and informative picture of the human chromosomes, genes and their biological function.
- PARACRINE FACTORS AND THEIR RECEPTORS IN BLOOD VESSEL FORMATION
The ability to grow new blood vessels and to cause old blood vessels to regress is regulated by the interplay of several paracrine factors and their receptors. New studies have revealed that combinations of these factors may be critical in permitting angiogenesis.
- PESTICIDE SYNERGISM QUESTIONED
A recent paper claimed that when two weakly estrogenic pesticides are brought together, they interact to produce an effect about a thousand-fold greater than the expected additive amount. This paper has been criticized by other investigators who do not see any estrogenic synergy when these compounds are put together.
- PITX-2: THE HEART AND GUTS OF LEFT-RIGHT ASYMMETRYNULL
Whereas nodal gene expression is a critical point in establishing left-right asymmetry in frogs, birds, and mammals, it apparently acts through the transcription factor Pitx-2 which is expressed in those organs having left-right asymmetry.
- Radiation hybrid mapping of cDNAs, ESTs and SSLPs in the zebrafish
A whole-genome radiation hybrid panel for the zebrafish was generated by the lab of P. N. Goodfellow by fusing an irradiated zebrafish donor cell line with a recipient hamster cell line (Kwok, C. et al. (1998) Nucleic Acids Res 26, 3562-6). Random fragments of the zebrafish chromosomes are integrated into the hamster chromosomes or retained as separate minichromosomes. The radiation-induced breakpoints in the zebrafish genome can be used for mapping in a manner analogous to recombination breakpoints in a genetic mapping approach. However, in the radiation hybrid approach the breakage frequency is higher, allowing higher resolution, and map distances more closely reflect actual physical distances. Almost any amplifiable sequence can be scored for its presence or absence in the hybrids, without a need for polymorphism.
- REASSESSMENT OF BMP EXPRESSION IN DUCK EMBRYONIC HINDLIMB.
Earlier experiments had suggested that the lack of BMP expression in the interdigital cells of the duck hindlimb allowed the webbing of the duck foot. Recent work shows that BMPs are expressed in these duck cells, just as they are in the chick cells.
- Research Overview
Our laboratory is interested in understanding the molecular regulatory circuits that function during vertebrate development. A basic premise of development is that sets of genes need to be precisely controlled at the transcriptional level to establish the correct specification and differentiation of tissue types and organ systems. Transcriptional regulation involves not only the ability to turn genes on or off, but also the ability to ensure that genes are expressed in a correct positional, temporal and quantitative fashion. An ideal model system in which to study the molecular regulation of gene expression is skeletal muscle development. All vertebrate muscles are derived from precursor cells (myoblasts) that colonize regions of the embryo, fuse into multinucleate myotubes and transcriptionally activate muscle-specific genes. Interestingly, this entire process is tightly regulated through signal transduction pathways that initiate extracellularly and that culminate in the transcriptional activation or repression of specific genes.
- Role of Notch in Wingless signalling in Drosophila.
Our interests in the role of Notch in Wingless signalling have led us to define, through a structure/function analysis, two different functions of Notch. In the context of the development and patterning of the nervous systems and the muscles, one of these functions is that of lateral inhibition and is involved in the suppression of cell fates. The Delta gene product is the ligand for this function which is implemented through the nuclear protein, Suppressor of Hairless. The second function is independent of Su(H) and is involved in the assignation rather than the suppression of cell fates. We believe that Wingless is the ligand in this process. We are involved in several projects geared towards the understanding of this second function and its relationship to lateral inhibition
- Serge Côté Laboratory (Quebec)
Genetic and molecular analysis of embryonic development in Drosophila
- Somite formation in the zebrafish
Somites are segmentally repeated mesodermal structures within the vertebrate embryo that give rise to the vertebrae and muscle of the trunk and tail. A recent large-scale screen for developmental mutants of the zebrafish, Danio rerio, identified mutations in five complementation groups that affect the anterior-posterior pattern of the somites: fused somites (fss), beamter (bea), after eight (aei), deadly seven (des) and white tail (wit). Both embryological and molecular genetic techniques are being used to further characterize the role that fss, bea, aei, and des play in somitogenesis and to identify the affected genes. Moreover, cross-species experiments will be used to elucidate the extent of any evolutionary conservation of the regulatory networks involved in segmentation. Thus, this analysis is aimed at both understanding the mechanism by which the paraxial mesoderm is segmented in the zebrafish and determining the extent of conservation between species of genetic regulatory networks involved in segmentation.
- SFB236 SFB271 SFB330 Sonderforschungsbereiche der Universität Göttingen
- SPECIFICATION OF LEG FATE IN DROSOPHILA BY ANTENNAPEDIA
The Antennapedia gene appears to function to specify leg development by inhibiting the expression of the homothorax gene. In the absence of the Antennapedia protein, the homodenticle protein facilitates the transfer of the Extradenticle protein into the nucleus, and the appendage to becomes specified as an antenna.
- SPERMATOGONIAL SYNCYTIA: BRIDGES TO THE FUTURE
New studies on spermatogonial ring canals in mammals and insects reveal that syncytia formation is a highly conserved property of spermatogenesis and that there are several interesting variations on this theme.
- TBX6 AND THE SPECIFICATION OF PARAXIAL MESODERM
When the Tbx6 gene is knocked out of mouse embryos, the somitic mesoderm becomes specified as neural ectoderm. Trunk regions have no somites but rather three neural tubes.
- THE AUTONOMOUS SPECIFICATION OF THE ENDODERM.
The amphibian endoderm is specified autonomously, without having to be induced. Three newly discovered genes appear to be critical in this process.
- The C. elegans Genome Project
The C. elegans Genome Project The C. elegans sequencing project is a collaboration between the Sanger Centre, Hinxton Hall, Cambridge and the Genome Sequencing Center at the Washington University School of Medicine, St. Louis.
- The Development of the Caenorhabditis elegans Vulva
The Development of the Caenorhabditis elegans Vulva, a model problem of developmental biology involving cell differentiation, cell-cell signalling and (possibly) morphogen gradients. Mark Blaxter for Developmental Biology 3m, ICAPB, University of Edinburgh
- THE ESTABLISHMENT OF OOCYTE POLARITY.
In some species, the oocyte is derived from a flagellated primordial germ cell. In sevearl of these species, the future animal cap of the cell is marked by the flagellum of the primordial germ cell.
- THE fringe GENE AND THE DIFFERENTIATION OF THE INSECT WING
The difference in the expression of the apterous transcription factor between dorsal and ventral wing surfaces initiates a cascade of reciprocal interactions that create the two different cell types.
- The Interactive Fly
A cyberspace guide to Drosophila genes and their roles in development
- The Jackson Laboratory Backcross DNA Panel Mapping
Resource
The BC Panel Mapping Resource maintains and distributes small aliquots of DNA from panels of 94 backcross animals from the cross (C57BL/6J x M. spretus) x C57BL/6J, called BSB panel 1, and a similar BSS panel 2 made up of DNA from the reciprocal backcross (C57BL/6JEi x SPRET/Ei) x SPRET/Ei. We are providing these DNAs in microtiter format to other investigators interested in mapping loci using this densely marked mapping cross resource. We provide technical support for defining the necessary polymorphisms by PCR, and once these are defined, we ship the backcross DNAs as 125 ng/ul aliquots to be diluted for use as PCR templates for mapping experiments. If Southern blotting is the only mapping option, please contact us for further discussion.
- THE L1 FAMILY OF NEURAL CELL ADHESION MOLECULES.
The L1 family of neural cell adhesion molecules consists of L1-CAMs, neurofascins, and Nr-CAMs. Mutations in the human gene encoding L1 can cause a set of hereditary neurological syndromes.
- THE NEBENKERN AND FUZZY ONIONS
The Nebenkern is a mitochondrial aggregate surrounding the microtubules of the insect sperm. The fuzzy onions gene of Drosophila encodes a GTPase protein that is necessary for the fusion of the mitochondria into the Nebenkern.
- THE REELER MUTATION: A DEFECT IN NEURONAL LAMINATION.
The cortical layers of reeler mice appear inverted from those of wild-type mice. The defect appears to be in an extracellular matrix protein, Reelin, that is secreted by a particular set of neurons. A similar phenotype is produced by mice lacking the disabled-1 protein. This protein may be in the pathway that allows young neurons to respond to Reelin.
- THE REGULATION OF CHICK SOMITOGENESIS.
The timing of somite formation and the placement of the division between the forming somite and the unsegmented mesoderm appears to be regulated by the dynamic expression of the hairy gene.
- THE SECRETION OF FRZB and DICKKOPF-1 BY THE ORGANIZER INDUCE THE FORMATION OF
In addition to protecting the dorsal mesoderm and ectoderm from the ventrolateralizing effects of the BMPs, the anterior region of the organizer also secretes proteins that block the Wnt signal. Wnt-8 is another protein that is important in promoting the ventrolateral mesoderm and ectoderm. New studies suggest that the blocking Wnt-8 and the BMPs is critical in inducing the head, while blocking the BMPs alone is necessary for inducing the trunk.
- Tübingen Drosophila stock collection
The Tübingen Drosophila stock collection contains approximately 1700 stocks, mostly mutants isolated in our lab. Our stocklist is accessible through FlyBase: Stocklist in .csv format (comma-separated list) Stocklist in .rpt format (for import into PC databases) These files contain all Drosophila stocks currently maintained in the Nüsslein-Volhard lab, and replace the previously published list: Tearle, R., and Nüsslein-Volhard, C. (1987). Tübingen mutants and stock list. Dros Inf Serv 66, 198-269.
- Tübingen zebrafish stockcenter
The stockcenter keeps about 400 mutant lines of Danio rerio, which are publicly available for scientific research. In addition the stockcenter is participating in the mapping of mutants in the genome. In collaborations with scientists in the Tübingen labs, as well as other laboratories, the stockcenter collection of mutants is screened for various phenotypic traits not covered in the original screen.
- Universität Bielefeld, Lehrstuhl für Entwicklungsbiologie
- UPDATE ON HOMEOTIC GENES I. COFACTORS.
The specificity of the interactions between homeodomain proteins and their DNA recognition elements depends upon the interaction of the homeodomain protein with other proteins such as Extradenticle. There are several models as to how this interaction may work.
- UPDATE ON HOMEOTIC GENES II. THE HEAD
However, other genes, such as Orth
The Hox genes of flies and vertebrates do bnot specify the head region. However, other genes, such as Orthodenticle appear to specify the head regions in both insects and mammals.
- UPDATE ON HOMEOTIC GENES II. THE HEAD (
The Hox genes of flies and vertebrates do bnot specify the head region. However, other genes, such as Orthodenticle appear to specify the head regions in both insects and mammals.
- UPDATE ON MATERNAL EFFECT MUTANTS IN DROSPHILA.
Recent studies on maternal effect genes in Drosophila have highlighted such phenomena as the instability of the bicoid message and the mechanism by which Nanos protein inhibits hunchback message translation.
- VALPROIC ACID TERATOGENESIS.
Valproic acid is a drug commonly used for the treatment of epilepsy. Children born to women taking this drug often have skeletal anomalies. The mechanism of valproic acid teratogenesis may involve the downregulation of the Pax-1 gene in the portion of the somites that gives rise to vertebral cartilage.
- VERA, A PROTEIN IMPLICATED IN Vg1 mRNA TRANSPORT TO THE VEGETAL CORTEX
Recent studies have identified a protein made during Xenopus oogenesis which specifically binds the 3'UTR of the Vg1 message. This protein may bind this mRNA to a set of endoplasmic reticulum vesicles that become translocated to the vegetal cortex.
- Virtual Library: Developmental Biology
© 2000 by Kurt Stüber