Gene regulation in Drosophila spermatogenesis: Analysis of protein binding at the translational control element TCE

Abstract

We have previously identified a 12 nucleotide long sequence element, the TCE, that was demonstrated to be necessary for translational control of expression in the male germ line of Drosophila melanogaster (Schäfer et 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 position +28 relative to the transcription start site. In this paper we analyse the mode of action of this element. We show that protein binding occurs at the TCE after incubation with testis protein extracts from Drosophila melanogaster. While several proteins are associated with the translational control element in the RNA, only one of these proteins directly crosslinks to the sequence element. The binding activity is exclusively observed with testis protein extracts but can be demonstrated with testis extracts from other Drosophila species as well, indicating that regulatory proteins involved in translational regulation in the male germ line are conserved. Although binding to the TCE can occur independent of its position relative to the transcription start site of the in vitro transcripts, its function in vivo is not exerted when shifted further downstream within the 5' UTR of a fusion gene. In addition to being a translational control element the TCE also functions as a transcriptional regulator. Consequently, a DNA-protein complex is also formed at the TCE. In contrast to the RNA-protein complexes we find DNA-protein complexes with protein extracts of several tissues of Drosophila melanogaster.

Specific Binding of a 47-Kilodalton Protein to the 3' Untranslated Region of Rat Transition Protein 2 Messenger Ribonucleic Acid1

“…6; Trpl). This indicated that the RNA-protein interaction does not solely depend on the primary sequence of the motif, as has been described for the translational control element binding site of the Mst(3)CPG gene family in spermatogenesis of Drosophila [23], but that the secondary structure of TNP2-3'UTR might be important as well. This was confirmed by analysis of the potential RNA structure of TNP2-3'UTR using the MFOLD computer program of Jaeger et al [22].…”

Post–transcriptional control of gene expression during spermatogenesis

“…Transgenic analysis has demonstrated convincingly that the TCE is required for translational control in vivo and that the position of the TCE in the 5Ј UTR is critical for translational repression. 28 TCE elements have been found in other Drosophila mRNAs as well, although their position within the 5Ј UTR does not appear to be conserved as stringently as that for the ( ) 29 Mst 3 CGP mRNAs. Similar elements in murine spermatogenic mRNAs have not been described.…”

Iron regulatory protein prevents binding of the 43S translation pre-initiation complex to ferritin and eALAS mRNAs.

“…The regulation of a family of mRNAs involved in spermatogenesis in Drosophila melanogaster, including Mst87F, is mediated by a conserved element in the 5' UTR of these mRNAs. As with ferritin, the position of this element with respect to the cap structure is conserved and movement of this element further downstream severely impedes regulation (Kempe et al, 1993). In addition, the mRNAs encoding different ribosomal proteins are translationally regulated via cap-proximal elements in many species, ranging from L32 in Saccharomyces cerevisiae (Dabeva and Warner, 1993) to L30, L32 and S16 in human cells (Levy et al, 1991).…”