PDF(Pubmed)
Abstract：
Spliceosome assembly contributes an important but incompletely understood aspect of splicing regulation. Prp45 is a yeast splicing factor which runs as an extended fold through the spliceosome, and which may be important for bringing its components together. We performed a whole genome analysis of the genetic interaction network of the truncated allele of PRP45 (prp45(1-169)) using synthetic genetic array technology and found chromatin remodellers and modifiers as an enriched category. In agreement with related studies, H2A.Z-encoding HTZ1, and the components of SWR1, INO80, and SAGA complexes represented prominent interactors, with htz1 conferring the strongest growth defect. Because the truncation of Prp45 disproportionately affected low copy number transcripts of intron-containing genes, we prepared strains carrying intronless versions of SRB2, VPS75, or HRB1, the most affected cases with transcription-related function. Intron removal from SRB2, but not from the other genes, partly repaired some but not all the growth phenotypes identified in the genetic screen. The interaction of prp45(1-169) and htz1Δ was detectable even in cells with SRB2 intron deleted (srb2Δi). The less truncated variant, prp45(1-330), had a synthetic growth defect with htz1Δ at 16°C, which also persisted in the srb2Δi background. Moreover, htz1Δ enhanced prp45(1-330) dependent pre-mRNA hyper-accumulation of both high and low efficiency splicers, genes ECM33 and COF1, respectively. We conclude that while the expression defects of low expression intron-containing genes contribute to the genetic interactome of prp45(1-169), the genetic interactions between prp45 and htz1 alleles demonstrate the sensitivity of spliceosome assembly, delayed in prp45(1-169), to the chromatin environment.
摘要：
剪接体组装有助于剪接调节的重要但不完全理解的方面。Prp45是一种酵母剪接因子，它作为一个延伸的折叠穿过剪接体，这对于将其组件组合在一起可能很重要。我们使用合成遗传阵列技术对PRP45（prp45（1-169））的截短等位基因的遗传相互作用网络进行了全基因组分析，并发现染色质改型和修饰体为丰富的类别。与相关研究一致，H2A.Z编码HTZ1，以及SWR1，INO80和SAGA复合物的成分代表了突出的相互作用者，htz1赋予最强的生长缺陷。因为Prp45的截短不成比例地影响了含内含子基因的低拷贝数转录本，我们制备了携带无内含子版本的SRB2,VPS75或HRB1的菌株,这是受转录相关功能影响最大的病例.从SRB2中去除内含子，但不从其他基因中去除，部分修复了遗传筛选中确定的一些但不是所有的生长表型。即使在SRB2内含子缺失（srb2Δi）的细胞中，也可以检测到prp45（1-169）和htz1Δ的相互作用。截断较少的变体，prp45(1-330),在16°C时具有htz1Δ的合成生长缺陷，它也坚持在srb2Δi背景中。此外，htz1Δ增强了prp45（1-330）依赖的pre-mRNA高和低效率剪接者的过度积累，基因ECM33和COF1。我们得出的结论是，尽管低表达内含子基因的表达缺陷有助于prp45（1-169）的遗传相互作用，prp45和htz1等位基因之间的遗传相互作用证明了剪接体组装的敏感性，延迟在prp45（1-169），染色质环境。
