The molecular characterization of sex-specific piRNA transcription and snRNA transcription in C. elegans

项目摘要 线虫性别特异的piRNA转录和SnRNA转录的分子特征。 Piwi相互作用RNA(PiRNAs)在抑制生殖系中的转座子方面起着关键作用。转座子的丢失- 靶向piRNAs可能会导致特定性别的后果，导致基因组不稳定和不孕。然而， 性别特异的piRNA表达机制在很大程度上仍不清楚。最近的研究表明， SNPC-4是SnRNA转录所必需的核心因子，也是线虫piRNA转录所必需的 并表明SnRNA转录机制可能被增选来转录piRNAs。 因此，识别转录因子并表征决定性别的特定蛋白质结构域- 特定的piRNA和SnRNA转录特异性将解决这一关键的知识鸿沟。小核电 RNA激活蛋白复合体(SNAPc)是由SNAPC1、SNAPC1和SNAPC1组成的保守的异源三聚体复合体。 SNAPC3和SNAPC4，促进哺乳动物中的SnRNA转录。与哺乳动物不同，线虫有 几个在piRNA生物发生中具有性别二态作用的SNAPC1的同源基因。我的初步数据显示 SNPC-1.2促进雌性piRNA转录，而SNPC-1.3是已知的雄性piRNA转录因子。 此外，我的初步数据显示，线虫SNAPC3同源基因SNPC-3.4促进了SnRNA的生物发生， 而SNPC-3.1和SNPC-3.2冗余地驱动男性和女性piRNA的表达。我会调查的 我的假设是SNPC-1.2是一个真正的女性piRNA转录因子，并且含有独特的蛋白质基序 赋予雌性piRNA表达，而SNPC-1.3中的不同结构域指定雄性piRNA表达(目的 1)。此外，我预测SNPC-3.4是一个SnRNA生物发生因子，而SNPC-3.1和SNPC-3.2起冗余作用 来驱动piRNA转录。类似于SNPC1家族，我预测SNPC-3.4中的不同结构域 和SNPC-3.1/3.2分别规定了它们在snRNA和piRNA基因组座位上的招募和转录 (目标2)。总的来说，这些数据将阐明SnRNA和雌性和雄性piRNA转录复合体。 并鉴定产生SnRNA和性别特异的piRNA转录的蛋白质基序。这项工作可能会有 对治疗由piRNA异常表达和不同神经元引起的生育缺陷的启示 与短链RNA调控不当有关的疾病，如肌萎缩侧索硬化症。

Project Summary The molecular characterization of sex-specific piRNA transcription and snRNA transcription in C. elegans. PIWI-interacting RNAs (piRNAs) play key roles in repressing transposons in the germline. Loss of transposon- targeting piRNAs can have sex-specific consequences leading to genomic instability and infertility. However, the mechanisms of sex-specific piRNA expression remain largely unknown. Recent studies have revealed that SNPC-4, a core factor required for snRNA transcription, is also essential for piRNA transcription in C. elegans and suggests that the snRNA transcriptional machinery may have been co-opted to transcribe piRNAs. Therefore, identifying the transcription factors and characterizing the specific protein domains that dictate sex- specific piRNA and snRNA transcriptional specificity will address this critical knowledge gap. The small nuclear RNA activating protein complex (SNAPc) is a conserved heterotrimeric complex consisting of SNAPC1, SNAPC3, and SNAPC4 that facilitates snRNA transcription in mammals. Unlike mammals, C. elegans have several orthologs of SNAPC1 that have sexually dimorphic roles in piRNA biogenesis. My preliminary data show that SNPC-1.2 promotes female piRNA transcription while SNPC-1.3 is a known male piRNA transcription factor. Furthermore, my initial data show the C. elegans SNAPC3 ortholog, SNPC-3.4, facilitates snRNA biogenesis, while SNPC-3.1 and SNPC-3.2 act redundantly to drive both male and female piRNA expression. I will investigate my hypothesis that SNPC-1.2 is a bona fide female piRNA transcription factor and harbors unique protein motifs conferring female piRNA expression, while distinct domains in SNPC-1.3 specify male piRNA expression (Aim 1). Additionally, I predict SNPC-3.4 is a snRNA biogenesis factor, while SNPC-3.1 and SNPC-3.2 act redundantly to drive piRNA transcription. Analogous to the SNPC1 family, I predict that distinct domains within SNPC-3.4 and SNPC-3.1/3.2 specify their recruitment and transcription at snRNA and piRNA genomic loci, respectively (Aim 2). Collectively, these data will elucidate the snRNA and female and male piRNA transcriptional complexes and identify the protein motifs that engender snRNA and sex-specific piRNA transcription. This work may have implications in treating fertility defects that are due to abnormal piRNA expression as well as different neuronal diseases associated with snRNA misregulation such as ALS.