CENP-C is involved in chromosome segregation, mitotic checkpoint function, and kinetochore assembly
CENP-C is involved in chromosome segregation, mitotic checkpoint function, and kinetochore assembly
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DOI：
10.1091/mbc.e07-01-0045
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发表时间：
2007-06-01
影响因子：
3.3
通讯作者：
Fukagawa, Tatsuo
中科院分区：
文献类型：
--
作者：
Kwon, Mi-Sun;Hori, Tetsuya;Fukagawa, Tatsuo
CENP-C 是一种保守的内着丝粒成分。为了了解 CENP-C 在着丝粒中的精确作用，我们创建了一种细胞系，该细胞系通过四环素诱导系统条件性敲除 CENP-C，其中靶蛋白在转录水平失活。我们发现 CENP-C 失活会导致有丝分裂延迟。然而，对活细胞的观察表明，CENP-C敲除细胞在有丝分裂延迟后没有正常的细胞分裂而进展到下一个细胞周期。有时观察到在随后的细胞死亡之前具有两个细胞核的间期细胞。我们还发现，类似 60% 的 CENP-C 缺陷细胞即使在诺考达唑治疗后也没有 Mad2 信号，这表明 CENP-C 的缺乏会损害 Mad2 纺锤体检查点通路。我们还观察到 CENP-C 缺陷细胞着丝粒 Mis12 复合蛋白的信号强度显着降低。在敲除CENP-K（CENP-H复合蛋白的成员）的细胞中，CENP-C信号在间期细胞核中也较弱，但在有丝分裂染色体中则不然。这些结果表明CENP-C在间期核中的着丝粒定位发生在Mis12复合物定位的上游和CENP-H复合物定位的下游。
CENP-C is a conserved inner kinetochore component. To understand the precise roles of CENP-C in the kinetochore, we created a cell line with a conditional knockout of CENP-C with the tetracycline-inducible system in which the target protein is inactivated at the level of transcription. We found that CENP-C inactivation causes mitotic delay. However, observations of living cells showed that CENP-C-knockout cells progressed to the next cell cycle without normal cell division after mitotic delay. Interphase cells with two nuclei before subsequent cell death were sometimes observed. We also found that similar to 60% of CENP-C- deficient cells had no Mad2 signals even after treatment with nocodazole, suggesting that lack of CENP-C impairs the Mad2 spindle checkpoint pathway. We also observed significant reductions in the signal intensities of Mis12 complex proteins at centromeres in CENP-C- deficient cells. CENP-C signals were also weak in interphase nuclei but not in mitotic chromosomes of cells with a knockout of CENP-K, a member of CENP-H complex proteins. These results suggest that centromere localization of CENP-C in interphase nuclei occurs upstream of localization of the Mis12 complex and downstream of localization of the CENP-H complex.