MOBILE MINOS ELEMENTS FROM DROSOPHILA-HYDEI ENCODE A 2-EXON TRANSPOSASE WITH SIMILARITY TO THE PAIRED DNA-BINDING DOMAIN

Elements related to the Tc1-like Mines mobile element have been cloned from Drosophila hydei and sequenced. Southern blot and sequence analy ses show that (i) the elements are actively transposing in the Droseph ila hgdei germ line, (ii) they are characterized by a striking degree of sequence and size homogeneity, and (iii) like Tc1, they insert at a TA dinucleotide that is probably duplicated during the process. The n ucleotide sequences of two elements, Minos-2 and Minos-3, differ at on ly one position from each other and contain two nonoverlapping open re ading frames that are separated by a putative 60-nucleotide intron. Th e amino-terminal part of the Minos putative transposase shows sequence similarity to the paired DNA-binding domain. Forced transcription of a modified Minos element that was introduced into the Drosophila melan ogaster germ line by P element-mediated transformation resulted in the production of accurately spliced polyadenylylated RNA molecules. It i s proposed that Minos-2 and/or Minos-3 may encode an active transposas e containing an amino-terminal DNA-binding domain that is distantly re lated to the paired DNA-binding domain.