Prp8 impacts cryptic but not alternative splicing frequency
Prp8 impacts cryptic but not alternative splicing frequency
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DOI：
10.1073/pnas.1819020116
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发表时间：
2019-02-05
影响因子：
11.1
通讯作者：
Zahler, Alan M.
中科院分区：
文献类型：
--
作者：
Mayerle, Megan;Yitiz, Samira;Zahler, Alan M.
前信使核糖核酸剪接必须以极高的保真度进行。剪接体在特定序列(5‘剪接点、3’剪接点和分支点)的引导下组装到前mRNA上。当剪接位点发生突变时，就像在许多遗传性疾病中一样，剪接体可能会异常地选择附近的假的或“隐蔽的”剪接位点，通常会导致蛋白质失去功能。剪接体如何区分真实的剪接位点和神秘的剪接位点，目前还知之甚少。我们对秀丽隐杆线虫进行了遗传筛查，以寻找影响剪接体使用隐藏剪接位点频率的细胞因素，并在核心剪接体组件Prp8中鉴定了两个改变隐藏剪接频率的等位基因。随后在酵母中进行的互补遗传和结构分析表明，这些等位基因与剪接体催化核心的稳定性有关。然而，尽管对隐蔽剪接有明显的影响，但对这些PRP-8突变线虫的高通量mRNA测序显示，总体可选剪接模式相对没有变化。我们的数据表明，剪接体进化出了减少隐蔽剪接发生的内在机制，这些机制与影响选择性剪接的机制不同。
Pre-mRNA splicing must occur with extremely high fidelity. Spliceosomes assemble onto pre-mRNA guided by specific sequences (5' splice site, 3' splice site, and branchpoint). When splice sites are mutated, as in many hereditary diseases, the spliceosome can aberrantly select nearby pseudo-or "cryptic" splice sites, often resulting in nonfunctional protein. How the spliceosome distinguishes authentic splice sites from cryptic splice sites is poorly understood. We performed a Caenorhabditis elegans genetic screen to find cellular factors that affect the frequency with which the spliceosome uses cryptic splice sites and identified two alleles in core spliceosome component Prp8 that alter cryptic splicing frequency. Subsequent complementary genetic and structural analyses in yeast implicate these alleles in the stability of the spliceosome's catalytic core. However, despite a clear effect on cryptic splicing, high-throughput mRNA sequencing of these prp-8 mutant C. elegans reveals that overall alternative splicing patterns are relatively unchanged. Our data suggest the spliceosome evolved intrinsic mechanisms to reduce the occurrence of cryptic splicing and that these mechanisms are distinct from those that impact alternative splicing.