GENE-REGULATION IN DROSOPHILA-SPERMATOGENESIS - ANALYSIS OF PROTEIN-BINDING AT THE TRANSLATIONAL CONTROL ELEMENT TCE

We have previously identified a 12 nucleotide long sequence element, t he TCE, that was demonstrated to be necessary for translational contro l of expression in the male germ line of Drosophila melanogaster (Scha fer at al., 1990). It is conserved among all seven members of the Mst( 3)CGP gene family, that encode structural proteins of the sperm tail. The TCE is invariably located in the 5' untranslated region (UTR) at p osition +28 relative to the transcription start site. In this paper we analyse the mode of action of this element. We show that protein bind ing occurs at the TCE after incubation with testis protein extracts fr om Drosophila melanogaster. While several proteins are associated with the translational control element in the RNA, only one of these prote ins directly crosslinks to the sequence element. The binding activity is exclusively observed with testis protein extracts but can be demons trated with testis extracts from other Drosophila species as well, ind icating that regulatory proteins involved in translational regulation in the male germ line are conserved. Although binding to the TCE can o ccur independent of its position relative to the transcription start s ite of the in vitro transcripts, its function in vivo is not exerted w hen shifted further downstream within the 5' UTR of a fusion gene. In addition to being a translational control element the TCE also functio ns as a transcriptional regulator. Consequently, a DNA-protein complex is also formed at the TCE. In contrast to the RNA-protein complexes w e find DNA-protein complexes with protein extracts of several tissues of Drosophila melanogaster. (C) 1993 Wiley-Liss, Inc.