Identification and characterisation of novel piRNA processing factors in C. elegans

线虫中新型 piRNA 加工因子的鉴定和表征

• 批准号: 504320275
• 负责人: Professor Dr. René Ketting, Ph.D.
• 金额: --
• 依托单位: Institut für Molekulare Biologie gGmbH (IMB)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/504320275?language=en
• 关键词: Identification; characterisation; novel; piRNA; processing

Identification and characterization of novel piRNA processing factors in C. elegans.Small RNA molecules can act as regulators in gene expression pathways. The precise recognition of targets is based on base pairing, and the sRNA thus acts as specificity factors, and consequently, their processing needs to be tightly controlled. One of the well-conserved small RNA silencing pathways is the so-called Piwi pathway. This pathway is one of the main surveillance systems in germ cells to keep transposable elements under control and is steered by small RNAs known as piRNAs. Given the wide diversity and varying nature of the transposon sequences, the piRNA sequence repertoire needs to be well controlled to avoid the recognition of host sequences. This happens by selecting specific transcripts as piRNA precursors, followed by distinct processing steps. Neither the selection process nor the processing steps are in general well understood.In the nematode Caenorhabditis elegans (C. elegans), the piRNAs are derived from specific, short RNA polymerase II transcripts. Following this, they are bound by a dedicated protein complex named PETISCO, which allows the processing of their 5′ end by an as-yet-unidentified nuclease. Whether this step is a compilation of different activities, such as de-capping, followed by exoribonucleolytic trimming, or is driven by a distinct endoribonucleolytic enzyme is unknown.We present preliminary data that implicate that the endoribonuclease is constituted by a heterodimeric protein complex that specifically acts on PETISCO-bound piRNA precursors in C. elegans. The proposed work plans are aimed to solidify this hypothesis and to understand this novel enzymatic activity. We want to learn about its 3-dimensional structure and how it is connected to PETISCO. In addition, we identified two additional factors that play a role in piRNA biogenesis and resemble proteins constituting dimeric endonuclease on the domain level. Our data suggest a potential modular heterodimeric assembly of potentially other types of nucleases, based on one of the two subunits of the piRNA processing nuclease. We aim to understand the function(s) of those complexes both at the biochemical and organismic levels.

C.中新型皮尔纳加工因子的鉴定和表征小RNA分子可以在基因表达途径中充当调节剂。靶标的精确识别基于碱基配对，因此sRNA充当特异性因子，因此，它们的加工需要严格控制。其中一个非常保守的小RNA沉默途径是所谓的Piwi途径。该途径是生殖细胞中保持转座因子处于控制之下的主要监视系统之一，并且由称为piRNA的小RNA操纵。鉴于转座子序列的广泛多样性和变化的性质，需要很好地控制皮尔纳序列库以避免识别宿主序列。这是通过选择特定的转录物作为皮尔纳前体，然后进行不同的加工步骤来实现的。无论是选择过程还是加工步骤通常都没有很好的理解。elegans），piRNA衍生自特异性短RNA聚合酶II转录物。在此之后，它们被一种名为PETISCO的专用蛋白质复合物结合，该复合物允许它们的5′端被一种尚未鉴定的核酸酶加工。这一步是否是不同活动的汇编，如脱帽，随后是外切核糖核酸裂解修剪，或由一个独特的内切核糖核酸裂解酶驱动是未知的。我们目前的初步数据表明，内切核糖核酸酶是由一个异二聚体蛋白复合物，特异性地作用于PETISCO结合的皮尔纳前体在C。优雅的拟议的工作计划旨在巩固这一假设，并了解这种新的酶活性。我们想了解它的三维结构以及它如何与PETISCO连接。此外，我们鉴定了在皮尔纳生物发生中起作用的另外两个因子，并且在结构域水平上类似于构成二聚核酸内切酶的蛋白质。 我们的数据表明，基于皮尔纳加工核酸酶的两个亚基之一，潜在的其他类型的核酸酶的潜在模块化异二聚体组装。我们的目标是了解这些复合物在生物化学和器官水平上的功能。