Serine/arginine-rich splicing factor 3 (SRSF3) regulates homologous recombination-mediated DNA repair.
Serine/arginine-rich splicing factor 3 (SRSF3) regulates homologous recombination-mediated DNA repair.
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DOI：
10.1186/s12943-015-0422-1
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发表时间：
2015-08-19
期刊：
影响因子：
37.3
通讯作者：
Zhang P
中科院分区：
文献类型：
--
作者：
He X;Zhang P
我们以前的工作发现，富含丝氨酸/精氨酸的剪接因子3(SRSF3)在人卵巢癌中过表达，并且SRSF3过表达是卵巢癌细胞生长和存活所必需的。SRSF3在卵巢癌中的作用机制尚不清楚。我们进行了基因芯片分析来分析SRSF3基因敲除细胞中的基因表达和剪接，并使用定量PCR和Western blotting来验证分析结果。我们用染色质免疫沉淀研究转录和直接重复绿色荧光蛋白报告实验研究同源重组介导的DNA修复(HRR)。我们在SRSF3基因敲除细胞中发现了687个表达改变的基因和807个剪接改变的基因。在表达改变的基因中，参与HRR的基因包括BRCA1、BRIP1和RAD51都是丰富的，都是下调的。我们证明BRCA1、BRIP1和RAD51的表达下调是由转录减少引起的，而不是由于无义介导的mRNA衰退增加所致。此外，我们发现，SRSF3基因敲除会损害细胞中的HRR活性，并增加γ-H_2AX的水平，这是双链DNA断裂的生物标志物。最后，我们观察到SRSF3基因敲除改变了H3K4特异性的组蛋白甲基转移酶KMT2C的剪接模式，并降低了单甲基化和三甲基化H3K4的水平。这些结果表明，SRSF3是一种新的HRR过程调节因子，可能通过表观遗传途径间接调节HRR相关基因的表达。SRSF3的这一新功能不仅解释了为什么SRSF3的过表达是卵巢癌细胞生长和生存所必需的，而且也为肿瘤转化的机制提供了新的视角。本文的在线版本(doi：10.1186/s12943-0150422-1)包含补充材料，授权用户可以使用。
Our previous work found that serine/arginine-rich splicing factor 3 (SRSF3) was overexpressed in human ovarian cancer and the overexpression of SRSF3 was required for ovarian cancer cell growth and survival. The mechanism underlying the role of SRSF3 in ovarian cancer remains to be addressed. We conducted microarray analysis to profile the gene expression and splicing in SRSF3-knockdown cells and employed quantitative PCR and western blotting to validate the profiling results. We used chromatin immunoprecipitation to study transcription and the direct repeat green fluorescent protein reporter assay to study homologous recombination-mediated DNA repair (HRR). We identified 687 genes with altered expression and 807 genes with altered splicing in SRSF3-knockdown cells. Among expression-altered genes, those involved in HRR, including BRCA1, BRIP1 and RAD51, were enriched and were all downregulated. We demonstrated that the downregulation of BRCA1, BRIP1 and RAD51 expression was caused by decreased transcription and not due to increased nonsense-mediated mRNA decay. Further, we found that SRSF3 knockdown impaired HRR activity in the cell and increased the level of γ-H2AX, a biomarker for double-strand DNA breaks. Finally, we observed that SRSF3 knockdown changed splicing pattern of KMT2C, a H3K4-specific histone methyltransferase, and reduced the levels of mono- and trimethylated H3K4. These results suggest that SRSF3 is a new regulator of HRR process, which possibly regulates the expression of HRR-related genes indirectly through an epigenetic pathway. This new function of SRSF3 not only explains why overexpression of SRSF3 is required for ovarian cancer cell growth and survival but also offers a new insight into the mechanism of the neoplastic transformation. The online version of this article (doi:10.1186/s12943-015-0422-1) contains supplementary material, which is available to authorized users.