Regulation of Spermatocyte Transcription by Testis TAFS

雄性配子发生的细胞分化程序依赖于一个强大的， 细胞类型特异性转录程序启动于减数分裂前期。我们发现睾丸- 一般PolII转录机器组件的特定同源物调节 果蝇精母细胞的终末分化基因。组织特异性形式的TAF、TBP和 TFIIA的亚基也与哺乳动物的精子发生有关。我们现在建议， 利用果蝇系统研究睾丸TAFs选择性调节的机制 精子细胞分化基因的转录。我们发现睾丸TAFs与 是定位Polycomb（Pc）转录沉默机制的组成部分所必需的 在初级精母细胞的核仁，这表明睾丸TAFs可能允许表达 通过隔离或拮抗负调节因子来靶向基因。我们将确定睾丸TAF 直接与Polycomb组分结合或在TFIID样或HAT样复合物中起作用， 在遗传学上，多梳和三胸调节复合物是否控制 初级精母细胞中的精子细胞分化基因。为了研究睾丸TAFs 调节基因表达，我们将绘制作为作用序列，使靶基因依赖于 睾丸TAFs，并确定这些是否可能结合激活剂表达， 精母细胞或阻遏物，必须由睾丸TAFs通过关键顺式作用基因突变来克服。 基序，测试Polycomb亚基、睾丸TAF或其他反式作用的控制区的占用率。 通过染色质免疫沉淀（ChIP）适当调节。来确定一个可能的合作伙伴 或与睾丸TAFs共同作用调节精子细胞转录的下游因子 分化基因，我们将研究和克隆法师，一个基因，具有类似的突变表型， 睾丸TAF我们提出的工作将揭示作用于细胞关键点的分子机制。 控制雄配子末端分化的遗传调控网络， 染色质沉默和核亚结构在调节原发性 精母细胞转录程序。

The dramatic cellular differentiationprogram of male gametogenesis depends on a robust, cell type specific transcription program initiated in meiotic prophase. We discovered that testis- specific homologs of general PolII transcription machinery components regulate transcription of terminal differentiation genes in Drosophila spermatocytes. Tissue-specific forms of TAFs, TBP and subunits of TFIIA have also been implicated in spermatogenesis in mammals. We propose now to exploit the Drosophila system to investigate the mechanism by which testis TAFs selectively regulate transcription of spermatid differentiation genes. We found that the testis TAFs co-localize with and are required for localization of components of the Polycomb (Pc)transcriptional silencing machinery to the nucleolus in primary spermatocytes, suggesting that testis TAFs might allow expression of target genes by sequestering or antagonizing a negative regulator. We will determine if testis TAFs bind directly to Polycomb components or act in a TFIID-like or HAT-like complex and test genetically whether the Polycomb and trithorax regulatory complexes control expression of spermatid differentiation genes in primary spermatocytes. To investigate how the testis TAFs regulate gene expression, we will map as-acting sequences that make target genes depend on the testis TAFs and determine whether these are likely to bind activators for expression in spermatocytes or repressers that must be overcome by the testis TAFs by mutation of key cz's-acting motifs, testing occupancy of control regions by Polycomb subunits, testis TAFs, or other trans-acting regulators as appropriate by chromatin immune-precipitation (ChIP). Toidentify a possible partner or downstream factor that may act with the testis TAFs to regulate transcription of spermatid differentation genes, we will investigate and clone mage, a gene with a similar mutant phenotype as the testis TAFs. Our proposed work will reveal molecular mechanisms that act at key points of the genetic regulatory network controlling terminal differentiation of male gametes and shed light possible roles for chromatin silencing and nuclear substructure in regulation of the primary spermatocyte transcription program.