Breast cancer associated gene 1 (BRCA1) function has been shown to be regulated by phosphorylation but the role of acetylation has not been determined. Therefore, we tested whether BRCA1 can be acetylated by the acetyltransferases P300/CBP-associated factor (pCAF), GCN5, and p300. p300 exhibited the highest level of BRCA1 acetylation; however, there was also a decrease in the total level of BRCA1. Therefore, we focused on pCAF and GCN5 because they both acetylated BRCA1 without affecting BRCA1 expression. Further analysis indicated that the acetylated form of BRCA1 is deacetylated by wild-type (WT) SIRT1, but not deacetylase mutant SIRT1, suggesting that SIRT1 is a specific deacetylase of BRCA1. We demonstrated that lysine 830 of BRCA1 is a preferential acetylation site by pCAF and tested its function in embryonic stem (ES) cells by changing lysine 830 to arginine using a transcription activator-like effector nuclease (TALEN) system. After exposure to DNA damage-inducing UV radiation, the viability of BRCA1 K830R mutant cells is greater than the WT ES cells. Further analysis using additional cell lines indicated that the BRCA1 K830R mutation impairs the intra-S checkpoint. Also, checkpoint kinase 1 (CHK1) phosphorylation was less in K830R cells as compared with WT cells after UV exposure. These data suggest that acetylation of BRCA1 on lysine 830 activates BRCA1 function at the intra-S checkpoint after DNA damage.

中文翻译：

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S内部检查点中的BRCA1功能通过pCAF / SIRT1轴的乙酰化作用激活。

乳腺癌相关基因1（BRCA1）的功能已显示受磷酸化调节，但尚未确定乙酰化的作用。因此，我们测试了BRCA1是否可以被乙酰转移酶P300 / CBP相关因子（pCAF），GCN5和p300乙酰化。p300表现出最高水平的BRCA1乙酰化；但是，BRCA1的总水平也有所下降。因此，我们专注于pCAF和GCN5，因为它们都使BRCA1乙酰化而不影响BRCA1的表达。进一步的分析表明，BRCA1的乙酰化形式被野生型（WT）SIRT1脱乙酰化，而脱乙酰基酶突变体SIRT1则不脱乙酰化，这表明SIRT1是BRCA1的特定脱乙酰基酶。我们证明BRCA1的赖氨酸830是pCAF的优先乙酰化位点，并通过使用转录激活因子样效应核酸酶（TALEN）系统将赖氨酸830变为精氨酸来测试其在胚胎干（ES）细胞中的功能。暴露于DNA损伤诱导的UV辐射后，BRCA1 K830R突变细胞的活力大于WT ES细胞。使用其他细胞系的进一步分析表明，BRCA1 K830R突变会损害S内检查点。同样，与紫外线照射后的野生型WT细胞相比，K830R细胞中的检查点激酶1（CHK1）磷酸化程度更低。这些数据表明，DNA损伤后，赖氨酸830上BRCA1的乙酰化会激活S内部检查点的BRCA1功能。暴露于DNA损伤诱导的UV辐射后，BRCA1 K830R突变细胞的活力大于WT ES细胞。使用其他细胞系的进一步分析表明，BRCA1 K830R突变会损害S内检查点。同样，与紫外线照射后的野生型WT细胞相比，K830R细胞中的检查点激酶1（CHK1）磷酸化程度更低。这些数据表明，DNA损伤后，赖氨酸830上BRCA1的乙酰化会激活S内部检查点的BRCA1功能。暴露于DNA损伤诱导的UV辐射后，BRCA1 K830R突变细胞的活力大于WT ES细胞。使用其他细胞系的进一步分析表明，BRCA1 K830R突变会损害S内检查点。同样，与紫外线照射后的野生型WT细胞相比，K830R细胞中的检查点激酶1（CHK1）磷酸化程度更低。这些数据表明，DNA损伤后，赖氨酸830上BRCA1的乙酰化会激活S内部检查点的BRCA1功能。