SU(STE) DIVERGED TANDEM REPEATS IN A Y-CHROMOSOME OF DROSOPHILA-MELANOGASTER ARE TRANSCRIBED AND VARIOUSLY PROCESSED

We report the organization and transcription of diverged tandemly repe ated Y-linked Su(Ste) genes that are considered as suppressors of test is-expressed X-linked-repeated Stellate genes that encode a protein sh aring extensive homology with beta-subunit of casein kinase 2. Cluster ing of restriction variants is confirmed. Size variants of Su(Ste) rep eats appeared to be nonhomogeneously distributed among the P1 phage cl ones. Different ways of Su(Ste) RNA processing because of the appearan ce of new splice sites and polyadenylation signals were detected. The high extent of homology between Stellate and Su(Ste) repeats suggested a possibility of Stellate suppression by antisense transcription of S u(Ste) elements. The detection of only ''sense'' Su(Ste) cDNAs in test is cDNA library allows us to reject this proposal. The genomic and cDN A clones are shown to be equally diverged. This indicates widespread r ather-than restricted transcription capacity of these repeats.