Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA.
Biochemistry, Cell and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI 48859, USA.
G3 (Bethesda). 2024 Mar 6;14(3). doi: 10.1093/g3journal/jkae007.
Gene regulation in changing environments is critical for maintaining homeostasis. Some animals undergo a stress-resistant diapause stage to withstand harsh environmental conditions encountered during development. MicroRNAs are one mechanism for regulating gene expression during and after diapause. MicroRNAs downregulate target genes posttranscriptionally through the activity of the microRNA-induced silencing complex. Argonaute is the core microRNA-induced silencing complex protein that binds to both the microRNA and to other microRNA-induced silencing complex proteins. The 2 major microRNA Argonautes in the Caenorhabditis elegans soma are ALG-1 and ALG-2, which function partially redundantly. Loss of alg-1 [alg-1(0)] causes penetrant developmental phenotypes including vulval defects and the reiteration of larval cell programs in hypodermal cells. However, these phenotypes are essentially absent if alg-1(0) animals undergo a diapause stage called dauer. Levels of the relevant microRNAs are not higher during or after dauer, suggesting that activity of the microRNA-induced silencing complex may be enhanced in this context. To identify genes that are required for alg-1(0) mutants to develop without vulval defects after dauer, we performed an RNAi screen of genes encoding conserved kinases. We focused on kinases because of their known role in modulating microRNA-induced silencing complex activity. We found RNAi knockdown of 4 kinase-encoding genes, air-2, bub-1, chk-1, and nekl-3, caused vulval defects and reiterative phenotypes in alg-1(0) mutants after dauer, and that these defects were more penetrant in an alg-1(0) background than in wild type. Our results implicate these kinases as potential regulators of microRNA-induced silencing complex activity during postdauer development in C. elegans.
在不断变化的环境中进行基因调控对于维持体内平衡至关重要。一些动物经历抗逆性休眠阶段,以耐受发育过程中遇到的恶劣环境条件。microRNAs 是调节休眠期间和休眠后基因表达的一种机制。microRNAs 通过 microRNA 诱导的沉默复合物的活性,在后转录水平下调靶基因。Argonaute 是结合 microRNA 和其他 microRNA 诱导的沉默复合物蛋白的 microRNA 诱导的沉默复合物的核心蛋白。在秀丽隐杆线虫体中,2 种主要的 microRNA Argonautes 是 ALG-1 和 ALG-2,它们部分冗余地发挥作用。alg-1 [alg-1(0)] 的缺失会导致明显的发育表型,包括阴道缺陷和皮细胞中幼虫细胞程序的重复。然而,如果 alg-1(0)动物经历称为 dauer 的休眠阶段,这些表型基本上就不存在了。在 dauer 期间或之后,相关 microRNAs 的水平并没有升高,这表明在这种情况下 microRNA 诱导的沉默复合物的活性可能增强。为了鉴定在 dauer 后发育过程中没有阴道缺陷的 alg-1(0)突变体所需的基因,我们对编码保守激酶的基因进行了 RNAi 筛选。我们专注于激酶,因为它们在调节 microRNA 诱导的沉默复合物活性方面具有已知的作用。我们发现,4 个激酶编码基因的 RNAi 敲低,air-2、bub-1、chk-1 和 nekl-3,导致 dauer 后 alg-1(0)突变体出现阴道缺陷和重复表型,并且这些缺陷在 alg-1(0)背景中比在野生型中更明显。我们的结果表明,这些激酶可能是秀丽隐杆线虫 postdauer 发育过程中 microRNA 诱导的沉默复合物活性的潜在调节剂。
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