BRCA1-associated growth arrest is RB-dependent
BRCA1-associated growth arrest is RB-dependent
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DOI：
10.1073/pnas.96.21.11866
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发表时间：
1999-10-12
影响因子：
11.1
通讯作者：
Liu, ET
中科院分区：
文献类型：
--
作者：
Aprelikova, ON;Fang, BS;Liu, ET
BRCA1是乳腺癌和卵巢癌的易感基因，具有生长抑制活性，其作用机制尚不清楚，当BRCA1被导入细胞时，可以抑制某些细胞系的生长，但不是所有细胞系的生长。为了揭示BRCA1抑制生长的机制，我们检测了一组细胞系在BRCA1过度表达时减少集落生长的能力。在测试的所有变量中，只有野生型pRb的细胞对BRCA1诱导的生长抑制敏感。在具有完整Rb基因的细胞中，HPV E7使pRb失活可以消除BRCA1造成的生长停滞。根据这些观察结果，我们发现BRCA1不能抑制RB-/-小鼠原代成纤维细胞对BrdUrd的摄取，并且与Rb+/+细胞相比，BRCA1对Rb+/-细胞DNA合成的抑制能力中等。我们进一步发现BRCA1蛋白与低磷酸化形式的pRb形成复合体，这种结合定位于BRCA1蛋白的304-394氨基酸，需要pRb的ABC结构域。参与与pRb相互作用的BRCA1片段的框内缺失完全取消了BRCA1的生长抑制特性。虽然已有报道BRCA1与P53相互作用，但我们发现P53状态并不影响BRCA1抑制集落形成的能力，我们的数据表明BRCA1的生长抑制功能至少部分依赖于Rb。
BRCA1 is a susceptibility gene for breast and ovarian cancer with growth-inhibitory activity for which the mechanism of action remains unclear, When introduced into cells, BRCA1 inhibits growth of some but not all cell lines. In an attempt to uncover the mechanism of growth suppression by BRCA1, we examined a panel of cell lines for their ability to reduce colony outgrowth in response to BRCA1 overexpression. Of all variables tested, only those cells with wild-type pRb were sensitive to BRCA1-induced growth suppression. In cells with an intact rb gene, inactivation of pRb by HPV E7 abrogates the growth arrest imposed by BRCA1. In accordance with these observations, we found that BRCA1 could not suppress BrdUrd uptake in primary fibroblasts from rb-/- mice and exhibited an intermediate ability to inhibit DNA synthesis in rb+/- as compared with rb+/+ cells, We further found that the BRCA1 protein complexes with the hypophosphorylated form of pRb, This binding is localized to amino acids 304-394 of BRCA1 protein and requires the ABC domain of pRb. In-frame deletion of BRCA1 fragment involved in interaction with pRb completely abolished the growth-suppressive property of BRCA1. Although it has been reported that BRCA1 interacts with p53, we find the p53 status did not affect the ability of BRCA1 to suppress colony formation, Our data suggest that the growth suppressor function of BRCA1 depends, at least in part, on Rb.