XVI International Botanical Congess

Transposition of the Mutator family of maize transposons is regulated by the MuDR element. MuDR contains mudrA and mudrB genes. MURA (mudrA product) is likely a transposase, the function of MURB (mudrB product) is unknown. To elucidate the nature of these proteins in planta, we have employed antibodies. Surprisingly, both proteins can be detected in inbred lines lacking MuDR. DNA analysis confirmed that all maize lines examined contain mudrA and mudrB homologs. Despite significant differences in transcript levels between active Mutator and inbred lines, MURA and MURB protein levels are similar, implicating strong post-transcriptional regulation in Mutator lines. We discuss the diversification of MuDR-like elements and the possible role(s) which encoded RNA and protein products may play in the regulation of Mutator activity.