Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
PhD Program in Molecular Life Sciences, University of Zurich and ETH Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
Cell Death Differ. 2019 Oct;26(10):2157-2178. doi: 10.1038/s41418-019-0291-z. Epub 2019 Feb 6.
Post-transcriptional control of mRNAs by RNA-binding proteins (RBPs) has a prominent role in the regulation of gene expression. RBPs interact with mRNAs to control their biogenesis, splicing, transport, localization, translation, and stability. Defects in such regulation can lead to a wide range of human diseases from neurological disorders to cancer. Many RBPs are conserved between Caenorhabditis elegans and humans, and several are known to regulate apoptosis in the adult C. elegans germ line. How these RBPs control apoptosis is, however, largely unknown. Here, we identify mina-1(C41G7.3) in a RNA interference-based screen as a novel regulator of apoptosis, which is exclusively expressed in the adult germ line. The absence of MINA-1 causes a dramatic increase in germ cell apoptosis, a reduction in brood size, and an impaired P granules organization and structure. In vivo crosslinking immunoprecipitation experiments revealed that MINA-1 binds a set of mRNAs coding for RBPs associated with germ cell development. Additionally, a system-wide analysis of a mina-1 deletion mutant compared with wild type, including quantitative proteome and transcriptome data, hints to a post-transcriptional regulatory RBP network driven by MINA-1 during germ cell development in C. elegans. In particular, we found that the germline-specific Argonaute WAGO-4 protein levels are increased in mina-1 mutant background. Phenotypic analysis of double mutant mina-1;wago-4 revealed that contemporary loss of MINA-1 and WAGO-4 strongly rescues the phenotypes observed in mina-1 mutant background. To strengthen this functional interaction, we found that upregulation of WAGO-4 in mina-1 mutant animals causes hypersensitivity to exogenous RNAi. Our comprehensive experimental approach allowed us to describe a phenocritical interaction between two RBPs controlling germ cell apoptosis and exogenous RNAi. These findings broaden our understanding of how RBPs can orchestrate different cellular events such as differentiation and death in C. elegans.
RNA 结合蛋白 (RBPs) 对 mRNA 的转录后调控在基因表达调控中起着重要作用。RBPs 与 mRNAs 相互作用，控制它们的生物发生、剪接、运输、定位、翻译和稳定性。这种调节的缺陷可导致从神经紊乱到癌症等广泛的人类疾病。许多 RBPs 在秀丽隐杆线虫和人类之间是保守的，并且有几种已知的 RBPs 调节成年秀丽隐杆线虫生殖系中的细胞凋亡。然而，这些 RBPs 如何控制细胞凋亡在很大程度上是未知的。在这里，我们在基于 RNA 干扰的筛选中鉴定出 mina-1(C41G7.3) 是一种新的凋亡调控因子，它仅在成年生殖系中表达。MINA-1 的缺失导致生殖细胞凋亡急剧增加、后代数量减少以及 P 颗粒的组织和结构受损。体内交联免疫沉淀实验表明，MINA-1 结合了一组编码与生殖细胞发育相关的 RBPs 的 mRNAs。此外，对 mina-1 缺失突变体与野生型的全系统分析，包括定量蛋白质组学和转录组学数据，提示在 C. elegans 生殖细胞发育过程中，MINA-1 驱动了一个基于 RBPs 的转录后调控网络。特别是，我们发现生殖系特异性 Argonaute WAGO-4 蛋白水平在 mina-1 突变体背景中增加。mina-1;wago-4 双突变体的表型分析表明，MINA-1 和 WAGO-4 的同时缺失强烈挽救了 mina-1 突变体背景中观察到的表型。为了加强这种功能相互作用，我们发现 mina-1 突变体动物中 WAGO-4 的上调导致对外源 RNAi 的敏感性增加。我们全面的实验方法使我们能够描述两个 RBPs 控制生殖细胞凋亡和外源 RNAi 的关键相互作用。这些发现拓宽了我们对 RBPs 如何在 C. elegans 中协调不同细胞事件（如分化和死亡）的理解。
