DEVELOPMENTAL EXPRESSION ANALYSIS OF THE 1731-RETROTRANSPOSON REVEALSAN ENHANCEMENT OF GAG-POL FRAMESHIFTING IN MALES OF DROSOPHILA-MELANOGASTER

Extensive analyses of Drosophila melanogaster retrotransposon transcri ptions in cultured cells or during development have been reported, but little is known about their translation during the development of the fly. Analysis of the translational products of the 1731 Drosophila me lanogaster retrotransposon in Kc Drosophila cultured cells has been re ported, showing the existence of primary products (Gag and Pol) and of processed polypeptides of Various sines. Study of 1731 retrotransposo n expression at both levels of transcription and translation during th e development of Drosophila melanogaster, is presented. 1731 transcrip ts were detected by in situ hybridization and 1731 proteins were detec ted by immunostaining and immunoblotting in embryos and in adult gonad s. 1731 transcripts and proteins were detected in the mesoderm and cen tral nervous system during embryonic development, in nurse cells and f ollicle cells in adult ovaries and in primary spermatocytes in adult t estes. Moreover, Western blot analysis of the 1731 proteins with anti- Gag or anti-Pol antibodies in gonads revealed that the 1731 mRNA could be translated differentially according to the expressing tissue: esse ntially, ovarian translation and/or processing of 1731 products is dif ferent from that operating in testes, where the Gag-Pol fusion polypro tein is the most prominent product. Our results indicate that expressi on of the 1731 mobile element is regulated not only at the transcripti onal level but also at the translational level, and that this regulati on is different in the two sexes. (C) 1997 Elsevier Science B.V.