CENP-B: a major human centromere protein located beneath the kinetochore.
CENP-B: a major human centromere protein located beneath the kinetochore.
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DOI：
10.1083/jcb.110.5.1475
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发表时间：
1990-05
期刊：
影响因子：
--
通讯作者：
Earnshaw WC
中科院分区：
文献类型：
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作者：
Cooke CA;Bernat RL;Earnshaw WC
三种结构相关的自身抗原 CENP-A (17 kD)、CENP-B (80 kD) 和 CENP-C (140 kD) 家族是人类着丝粒的最佳特征组成部分，并且它们被广泛认为是着丝粒的组成部分。动粒成分目前引起了人们极大的兴趣，因为这种结构长期以来被认为是微管附着在染色体上的位点，现在被认为是后期染色体运动的力产生位点。在本研究中，我们使用两种单特异性多克隆抗体以及新开发的一系列超小 1 nm 胶体金探针，通过免疫电子显微镜绘制了 CENP-B 在有丝分裂染色体中的分布图。我们惊讶地发现超过 95% 的 CENP-B 分布在着丝粒下方的着丝粒异染色质中。这有力地支持了 CENP-B 与 α-卫星异染色质特异性相关的其他新证据。尽管在某些情况下可以看到 CENP-B 集中在紧邻着丝粒下表面的位置，但外板实际上仍然未标记。对识别所有三种 CENP 抗原的人类自身免疫血清进行的类似分析揭示了着丝粒结构的另一个未预料到的特征。除了识别着丝粒异染色质中的抗原之外，自身抗血清还识别着丝粒侧面的抗原浓度。这种染色模式的差异可能反映了围绕动粒板的富含 CENP-C 和/或 CENP-A 的染色质“领子”的存在。
The family of three structurally related autoantigens CENP-A (17 kD), CENP-B (80 kD), and CENP-C (140 kD) are the best characterized components of the human centromere, and they have been widely assumed to be components of the kinetochore. Kinetochore components are currently of great interest since this structure, which has long been known to be the site of microtubule attachment to the chromosome, is now believed to be a site of force production for anaphase chromosome movement. In the present study we have mapped the distribution of CENP- B in mitotic chromosomes by immunoelectron microscopy using two monospecific polyclonal antibodies together with a newly developed series of ultra-small 1-nm colloidal gold probes. We were surprised to find that greater than 95% of CENP-B is distributed throughout the centromeric heterochromatin beneath the kinetochore. This strongly supports other emerging evidence that CENP-B is specifically associated with alpha-satellite heterochromatin. Although in certain instances CENP-B can be seen to be concentrated immediately adjacent to the lower surface of the kinetochore, the outer plate remains virtually unlabeled. Similar analysis with a human autoimmune serum that recognizes all three CENP antigens reveals an additional unsuspected feature of kinetochore structure. In addition to recognizing antigens in the centromeric heterochromatin, the autoantiserum recognizes a concentration of antigens lateral to the kinetochore. This difference in staining pattern may reflect the presence of a "collar" of chromatin rich in CENP-C and/or CENP-A encircling the kinetochore plates.