sgf73＋在裂殖酵母中的大规模遗传筛选

Large scale screening of genetic interaction with sgf73^+ in fission yeast

遗传相互作用(Genetic interaction,GI)直接提示了生物体内各个基因在功能上的关联性,为研究一个基因的潜在功能提供了线索。遗传筛选是研究基因遗传相互作用的重要方法。文章以SAGA(Spt-Ada-Gcn5 acetyltransferase)复合物去泛素化模块亚基基因sgf73+为查询基因,在裂殖酵母(Schizosaccharomyces pombe)中进行了大规模遗传筛选。结果显示,164个基因与sgf73+具有负遗传相互作用,42个基因具有正遗传相互作用。GO(Gene ontology)分析结果表明,这些基因富集于染色质修饰、DNA损伤修复、压力应答、RNA转录等生物过程。通过组蛋白修饰检测实验首次发现,sgf73+的缺失导致组蛋白H3K9、H4K16位点乙酰化水平下降,H3K4位点甲基化修饰水平上升。此外,系列稀释实验显示sgf73?菌株对DNA损伤试剂HU和CPT的敏感性提高,并且Sgf73参与高氧胁迫应答。这些结果显示sgf73+参与了染色质修饰、DNA损伤修复和高氧压力应答过程。

Genetic interaction （GI） not only suggests functional correlations between different genes in vivo, but also pro- vides clues for understanding the potential biological function of a specific gene. Screening of GI is an important method for understanding GI between different genes. In this study, we selected sgf73＋ as a query, which encodes a subunit of SAGA （Spt-Ada-Gcn5 acetyltransferase） complex deubiquitination module, to perform a large scale screening of GI in fission yeast. Our data showed that 164 genes had negative GIs whereas 42 genes had positive GIs with sgf73＋. GO （Gene ontology） analysis indicated that these genes were enriched in several important biological processes, including chromatin modification, DNA damage repair, cellular response to stress, RNA transcription and so on. By using histone modification detection, we showed for the first time that loss of sgf73＋ led to a decreased level of histone acetylation at H3K9 and H4K16 and an increased level of histone H3K4 methylation. Furthermore, the spot assay results showed that the sgf73△ cells exhibited increased sensitivity to DNA damage agents, HU and CPT, and sgf73＋ was involved in responses to hyperoxia stress.All these results suggested that sgf73＋ plays important roles in chromatin modification, DNA damage repair and hyperoxia responses.