Regulation of transcription of meiotic cell cycle and terminal differentiation genes by the testis-specific Zn-finger proteinmatotopetli

Abstract

A robust developmentally regulated and cell type specific transcriptional programme is activated in primary spermatocytes in preparation for differentiation of the male gametes during spermatogenesis. Work in Drosophila is beginning to reveal the genetic networks that regulate this gene expression. The Drosophila aly-class meiotic arrest loci are essential for activation of transcription of many differentiation-specific genes, as well as several genes important for meiotic cell cycle progression,thus linking meiotic cell cycle progression to cellular differentiation during spermatogenesis. The three previously described aly-class proteins(aly, comr and achi/vis) form a complex and are associated with chromatin in primary spermatocytes. We identify, clone and characterize a new aly-class meiotic arrest gene, matotopetli (topi), which encodes a testis-specific Zn-finger protein that physically interacts with Comr. The topimutant phenotype is most like achi/vis in that topi function is not required for the nuclear localization of Aly or Comr, but is required for their accumulation on chromatin. Most target genes in the transcriptional programme depend on both topi and achi/vis; however, a small subset of target genes are differentially sensitive to loss of topior achi/vis, suggesting that these aly-class predicted DNA binding proteins can act independently in some contexts.

The polyubiquitin gene Ubi-p63E is essential for male meiotic cell cycle progression and germ cell differentiation in Drosophila

“…Immunofluorescence was performed as previously described (Chen et al, 2005), using the following antibodies: mouse anti-GFP (1:200, Roche), rabbit anti-HA (1:200, Bethyl Laboratories), rabbit anti-Myc (1:1000, Santa Cruz Biotechnology), anti-Topi (1:1000) (Perezgasga et al, 2004), anti-Cyclin B (1:50, Developmental Studies Hybridoma bank) and anti-Fibrillarin (1:200, Cytoskeleton). Anti-uH2A (Millipore) staining was performed as described (Rathke et al, 2007).…”

Transcriptional regulation by Modulo integrates meiosis and spermatid differentiation in male germ line

“…Execution of the meiosis͞differentiation program requires a number of general transcriptional regulators collectively known as the meioticarrest genes. These include the genes of the aly group that encode subunits of the putative chromatin-modifying complex (2)(3)(4)(5)(6) and the genes of the can group that code for the subunits of testes-specific TFIID, which is involved in initiation of transcription as part of the preinitiation complex (2,7) and probably participates in displacement of the repressory Pc complexes from the testes-specific promoters (8). A number of meiotic regulators, such as cyclin B, boule, and twine, as well as many genes required for spermatid differentiation, are under the control of meiotic-arrest genes (2,6).…”

Drosophila danyis essential for transcriptional control and nuclear architecture in spermatocytes

“…In addition, with analyses in aly and topi mutants, we addressed whether tMAC function is required for Dany accumulation or localization. g-EGFP-dany and g-dany-EGFP were therefore crossed into males with transheterozygous combinations of strong alleles that are thought to abolish the function of sa, aly or topi completely Perezgasga et al, 2004;White-Cooper et al, 2000). Expression of EGFPtagged Dany was still observed in mutant testis, starting in early spermatocytes as in wild type, and reaching apparently normal levels.…”

“…The experiments involving temporally regulated expression in the salivary gland were performed with P{w + , UASt-EGFP-dany}III.1. The following alleles of meiotic arrest mutants were used in heteroallelic combinations: sa 1 and sa 2 Z3-0707 (BDSC #38441) and topi Z3-2139 (BDSC #38442) (Perezgasga et al, 2004). For the analysis of g-EGFP-dany expression in these meiotic arrest mutants, we used testis from heteroallelic mutants carrying one copy of the transgene.…”

“…They were identified based on a characteristic loss-offunction phenotype in which the testes fill up with spermatocytes failing to enter meiotic divisions and postmeiotic differentiation (Jiang et al, 2007;Lin et al, 1996;White-Cooper et al, 2000). Several genes of comparably recent origin and with similar mutant phenotypes (topi, comr, achi, vis) encode proteins interacting with tMAC (Ayyar et al, 2003;Jiang and White-Cooper, 2003;Perezgasga et al, 2004;Wang and Mann, 2003). A second protein complex of paramount importance for spermatocytespecific transcription is formed by testis-specific TATA-binding protein (TBP)-associated factors (tTAFs) in the genus Drosophila (Chen et al, 2005;Hiller et al, 2004;Li et al, 2009).…”