RNA helicases drive necessary rearrangements and ensure fidelity during the pre-mRNA splicing cycle. DEAD-box helicase DDX41 has been linked to human disease and has recently been shown to interact with DEAH-box helicase PRP22 in the spliceosomal C* complex, yet its function in splicing remains unknown. Depletion of DDX41 homolog SACY-1 from somatic cells has been previously shown to lead to changes in alternative 3′ splice site (3′ss) usage. Here, we show by transcriptomic analysis of published and novel data sets that SACY-1 perturbation causes a previously unreported pattern in alternative 3′ splicing in introns with pairs of 3′ splice sites ≤18 nt away from each other. We find that both SACY-1 depletion and the allele sacy-1(G533R) lead to a striking unidirectional increase in the usage of the proximal (upstream) 3′ss. We previously discovered a similar alternative splicing pattern between germline tissue and somatic tissue, in which there is a unidirectional increase in proximal 3′ss usage in the germline for ∼200 events; many of the somatic SACY-1 alternative 3′ splicing events overlap with these developmentally regulated events. We generated targeted mutant alleles of the Caenorhabditis elegans homolog of PRP22, mog-5, in the region of MOG-5 that is predicted to interact with SACY-1 based on the human C* structure. These viable alleles, and a mimic of the myelodysplastic syndrome-associated allele DDX41(R525H), all promote the usage of proximal alternative adjacent 3′ splice sites. We show that PRP22/MOG-5 and DDX41/SACY-1 have overlapping roles in proofreading the 3′ss.

中文翻译：

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剪接体解旋酶 DDX41/SACY-1 和 PRP22/MOG-5 都有助于校对近端 3' 剪接位点的使用

RNA 解旋酶驱动必要的重排并确保前 mRNA 剪接周期中的保真度。DEAD 盒解旋酶 DDX41 与人类疾病有关，并且最近被证明与剪接体 C* 复合物中的 DEAH 盒解旋酶 PRP22 相互作用，但其在剪接中的功能仍不清楚。先前已证明体细胞中 DDX41 同源物 SACY-1 的耗尽会导致替代 3' 剪接位点 (3'ss) 使用的变化。在这里，我们通过对已发表的和新颖的数据集进行转录组分析表明，SACY-1 扰动会导致内含子中的选择性 3' 剪接出现以前未报告的模式，其中成对的 3' 剪接位点彼此距离≤18 nt。我们发现 SACY-1 缺失和等位基因sacy-1(G533R)都会导致近端（上游）3'ss 的使用显着单向增加。我们之前发现种系组织和体细胞组织之间存在类似的选择性剪接模式，其中在~200个事件中，种系中近端3'ss的使用单向增加；许多体细胞 SACY-1 选择性 3' 剪接事件与这些发育调控事件重叠。我们在 MOG-5 区域生成了PRP22 的秀丽隐杆线虫同源物mog-5的靶向突变等位基因，根据人类 C* 结构，预计 MOG-5 会与 SACY-1 相互作用。这些可行的等位基因以及骨髓增生异常综合征相关等位基因 DDX41(R525H) 的模拟物都促进了近端替代相邻 3' 剪接位点的使用。我们发现 PRP22/MOG-5 和 DDX41/SACY-1 在校对 3’ss 方面具有重叠的作用。