SEQUENCE SIMILARITY OF PUTATIVE TRANSPOSASES LINKS THE MAIZE MUTATOR AUTONOMOUS ELEMENT AND A GROUP OF BACTERIAL INSERTION SEQUENCES

The Mutator transposable element system of maize is the most active tr ansposable element system characterized in higher plants. While Mutato r has been used to generate and tag thousands of new maize mutants, th e mechanism and regulation of its transposition are poorly understood. The Mutator autonomous element, MuDR, encodes two proteins: MURA and MURB. We have detected an amino acid sequence motif shared by MURA and the putative transposases of a group of bacterial insertion sequences . Based on this similarity we believe that MURA is the transposase of the Mutator system. In addition we have detected two rice cDNAs in gen bank with extensive similarity to MURA. This sequence similarity sugge sts that a Mutator-like element is present in rice. We believe that Mu tator, a group of bacterial insertion sequences, and an uncharacterize d rice transposon represent members of a family of transposable elemen ts.