Department of Biological Chemistry and Pharmacology, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA; Ohio State Biochemistry Program, Columbus, OH 43210, USA.
Department of Biological Chemistry and Pharmacology, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
Cell Rep. 2021 Aug 31;36(9):109640. doi: 10.1016/j.celrep.2021.109640.
The Piwi-interacting RNA (piRNA) pathway suppresses transposable elements and promotes fertility in diverse organisms. Maturation of piRNAs involves pre-piRNA trimming followed by 2'-O-methylation at their 3' termini. Here, we report that the 3' termini of Caenorhabditis elegans piRNAs are subject to nontemplated nucleotide addition, and piRNAs with 3' addition exhibit extensive base-pairing interaction with their target RNAs. Animals deficient for PARN-1 (pre-piRNA trimmer) and HENN-1 (2'-O-methyltransferase) accumulate piRNAs with 3' nontemplated nucleotides. In henn-1 mutants, piRNAs are shortened prior to 3' addition, whereas long isoforms of untrimmed piRNAs are preferentially modified in parn-1 mutant animals. Loss of either PARN-1 or HENN-1 results in modest reduction in steady-state levels of piRNAs. Deletion of both enzymes leads to depletion of piRNAs, desilenced piRNA targets, and impaired fecundity. Together, our findings suggest that pre-piRNA trimming and 2'-O-methylation act collaboratively to protect piRNAs from tailing and degradation.
Piwi 相互作用 RNA (piRNA) 途径抑制转座元件并促进多种生物的生育能力。piRNA 的成熟涉及前 piRNA 的修剪，然后在其 3' 末端进行 2'-O-甲基化。在这里，我们报告说，秀丽隐杆线虫 piRNA 的 3' 末端受到非模板核苷酸的添加，并且具有 3' 添加的 piRNA 与它们的靶 RNA 表现出广泛的碱基配对相互作用。缺乏 PARN-1（前 piRNA 修剪器）和 HENN-1（2'-O-甲基转移酶）的动物会积累具有 3' 非模板核苷酸的 piRNA。在 henn-1 突变体中，piRNA 在 3' 添加之前被缩短，而未修剪的 piRNA 的长同工型在 parn-1 突变体动物中优先被修饰。PARN-1 或 HENN-1 的缺失导致 piRNA 的稳态水平适度降低。两种酶的缺失都会导致 piRNA 的耗竭、piRNA 靶标的去沉默以及生育能力受损。总之，我们的发现表明，前 piRNA 修剪和 2'-O-甲基化协同作用，保护 piRNA 免受尾随和降解。
