Subcellular localization of the BRCA1 gene product in mitotic cells
Subcellular localization of the BRCA1 gene product in mitotic cells
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DOI：
10.1002/gcc.10105
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发表时间：
2002-11-01
影响因子：
3.7
通讯作者：
Mariani-Costantini, R
中科院分区：
文献类型：
--
作者：
Lotti, LV;Ottini, L;Mariani-Costantini, R
遗传性乳腺癌易感基因BRCA 1的产物是一种多功能蛋白，参与维持基因组完整性、转录共激活和控制细胞生长。BRCA 1缺陷细胞表现出染色体不稳定性。在有丝分裂过程中，BRCA 1与中心体中的γ-微管蛋白相互作用，中心体是有丝分裂纺锤体的关键元件。利用共聚焦显微镜和免疫金电子显微镜，我们调查了乳腺癌细胞中内源性BRCA 1相对于有丝分裂纺锤体标记物的分布。通过共聚焦分析，BRCA 1和β-微管蛋白共定位于有丝分裂纺锤体的微管和中心体。免疫金电子显微镜证实了这些结果，并进一步揭示，BRCA 1和α-微管蛋白共分布到中心粒的壁和中心粒周围纤维的中心体。在染色单体分离，共分布也检测到沿着个别纺锤体微管和在染色体上的微管插入的网站。在胞质分裂时，BRCA 1和α-微管蛋白共分布到中间体。免疫共沉淀支持全长BRCA 1与α-和β-微管蛋白的关联。这些结果与BRCA 1参与有丝分裂纺锤体的动力学和重复染色体的分离是一致的。(C)2002 Wiley-Liss，Inc.
The product of the hereditary breast cancer susceptibility gene BRCA1 is a multifunctional protein involved in the maintenance of genomic integrity, in transcriptional coactivation, and in the control of cell growth. BRCA1-deficient cells manifest chromosomal instability. During mitosis, BRCA1 is known to interact with gamma-tubulin in the centrosomes, key elements of the mitotic spindle. Using confocal microscopy and immunogold electron microscopy, we investigated the distribution of endogenous BRCA1 relative to mitotic spindle markers in breast cancer cells. By confocal analysis, BRCA1 and beta-tubulin colocalized to microtubules of the mitotic spindle and to the centrosomes. Immunogold electron microscopy confirmed these results and further revealed that BRCA1 and alpha-tubulin codistributed to the walls of the centrioles and to pericentriolar fibers at centrosomes. During chromatid segregation, codistribution was also detected along individual spindle microtubules and at sites of insertion of microtubules on chromosomes. At cytokinesis, BRCA1 and alpha-tubulin codistributed to the midbody. Coimmunoprecipitation supported the association of full-length BRCA1 with alpha- and beta-tubulin. These results are consistent with an involvement of BRCA1 in the dynamics of the mitotic spindle and in the segregation of duplicated chromosomes. (C) 2002 Wiley-Liss, Inc.