Page S L, Earnshaw W C, Choo K H, Shaffer L G
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
Hum Mol Genet. 1995 Feb;4(2):289-94. doi: 10.1093/hmg/4.2.289.
The stability of certain dicentric chromosomes in humans seems to result from inactivation of one centromere, yielding a functionally monocentric chromosome. Centromere protein C (CENP-C) was previously shown to be present at active centromeres but absent from the inactive centromere of one homologous dicentric rearrangement. We have combined indirect immunofluorescence detection of CENP-C and fluorescence in situ hybridization with chromosome-specific alpha-satellite DNA probes in a simultaneous assay to unequivocally identify the active and inactive centromeres of a dicentric (X;15) translocation. In both fibroblast and lymphoblast cell lines containing the translocation, the X chromosome centromere consistently had a primary constriction and CENP-C immunofluorescence, and is therefore the active centromere. CENP-C was never detected at the chromosome 15 centromere, which appears to be inactive. The inactivation pattern is apparently stable and observed in all cells with the translocation. Immunofluorescence with CREST serum revealed staining at both centromeres of the translocation, and thus was not specific to the active centromere. This study demonstrates the specificity of CENP-C to the active centromere in a non-homologous rearrangement and further establishes CENP-C as an essential component of a functional human centromere.
人类某些双着丝粒染色体的稳定性似乎源于一个着丝粒的失活，从而产生功能上的单着丝粒染色体。着丝粒蛋白C（CENP-C）先前已被证明存在于活性着丝粒中，但在一个同源双着丝粒重排的失活着丝粒中不存在。我们在一项同步检测中，将CENP-C的间接免疫荧光检测与荧光原位杂交技术结合，使用染色体特异性α-卫星DNA探针，以明确鉴定双着丝粒（X；15）易位的活性和非活性着丝粒。在含有该易位的成纤维细胞和淋巴母细胞系中，X染色体着丝粒始终具有主缢痕和CENP-C免疫荧光，因此是活性着丝粒。在15号染色体着丝粒处从未检测到CENP-C，其似乎是失活的。这种失活模式显然是稳定的，并且在所有具有该易位的细胞中都能观察到。用CREST血清进行的免疫荧光显示易位的两个着丝粒均有染色，因此并非活性着丝粒所特有。本研究证明了CENP-C在非同源重排中对活性着丝粒的特异性，并进一步确定CENP-C是功能性人类着丝粒的重要组成部分。
