Cis-acting regions sufficient for spermatocyte-specific transcriptional and spermatid-specific translational control of the Drosophila melanogaster gene mst(3)gl-9.

Abstract

In Drosophila spermatogenesis transcription occurs only premeiotically while translation can be detected also in postmeiotic spermatids. To analyse the underlying processes mst(3)gl‐9, a gene specifically expressed in the male germ cells of Drosophila melanogaster, was studied. The putative protein encoded by mst(3)gl‐9 is mostly composed of repetitive Cys‐Gly‐Pro motifs. The transcriptional and translational control of expression of mst(3)gl‐9 has been investigated by P‐mediated transformation. Only 102 bp of 5′ upstream sequences and the first 201 bp of the gene are sufficient to maintain the gene specific characteristics of expression, namely premeiotic transcription and postmeiotic translation separated by 3 days of development.

Expression of a gene duplication encoding conserved sperm tail proteins is translationally regulated in Drosophila melanogaster.

“…The amino acid composition of the rat protein corresponds very well to that of two proteins identified in the rat outer dense fibers (33) and even in bull outer dense fibers (5), allowing the authors the conclusion that rts 5/1 might be one of the genes encoding these proteins (6). This finding strongly enforces our previous hypothesis based on earlier Northern data as well as on analogies in the timing of specific differentiation processes late in spermiogenesis, that the Mst(3)CGP gene family codes for proteins of specific structures in the Drosophila sperm tail, the so-called satellites (21). These structures are formed late in spermiogenesis by the incorporation of electron-dense material in the accessory tubules of the axoneme (23) and are thought to be analogous to the mammalian outer dense fibers (1).…”

“…We show biochemically that translation of the Mst98C mRNAs is prevented in diploid stages of spermatogenesis and by analysis of male-sterile (ms) mutants that Mst98C protein synthesis is restricted to a short period at the end of spermiogenesis. In cytological preparations, the proteins are detected over the entire tail of elongated spermatids but not in round stages of spermatogenesis, again demonstrating late translation of these genes and supporting the hypothesis of their function as structural proteins in the sperm tail (21 (20). cDNA and genomic clone libraries used in the screening experiments were also as described by Kuhn et al (20).…”

“…4) results in hybridization not only of the two transcripts of 1.3 and 1.5 kb but also of transcripts of around 0.5 kb, demonstrating the sequence similarity based on the CGP repeats to the other members of the Mst(3)CGP gene family (Mst84Da, Mst84Db, Mst84Dc, Mst84Dd, and Mst87F [20,21]). Use of the 3' UTR of Mst98Cb as a probe (probe 3 in Fig.…”

“…These are quite advanced stages of sperm development, and both proteins must therefore be. synthesized very late in spermiogenesis, as has already been shown for the Mst87F-lacZ fusion protein (21). Since all of these mutations have so far been characterized initially only Fig.…”

“…We have already described five genes with these characteristics, namely, Mst87F (a gene for a malespecific transcript localized in polytene region 87F [21]) and a cluster of four genes at 84D named Mst84Da, Mst84Db, Mst84Dc, and Mst84Dd (20), to demonstrate a more general applicability of the gene regulation mechanisms. These five genes form the Mst(3)CGP gene family, since they all are located on chromosome 3 and encode proteins composed mainly of a repetitive Cys-Gly-Pro (CGP) motif.…”