Nilsson M, Krejci K, Koch J, Kwiatkowski M, Gustavsson P, Landegren U
Beijer Laboratory, Department of Medical Genetics, Uppsala, Sweden.
Nat Genet. 1997 Jul;16(3):252-5. doi: 10.1038/ng0797-252.
Chromosome centromeres, composed of repeated DNA sequences, orchestrate the correct segregation of chromatids in cell division. We have examined the centromeres of human chromosomes 13 and 21 by studying the distribution, in situ, of two alpha satellite sequences that differ in a single nucleotide position. This was possible using padlock probes, oligo-nucleotides that can be ligated into circles upon target recognition. The segregation of individual 13 and 21 homologues in a family was followed by monitoring of the signals from two differentially labelled probes, specific for either sequence variant. A characteristic arrangement of the repeat motifs in three separate spots, oriented transverse to the length axis of the metaphase chromosomes and bilaterally symmetric, indicates that only parts of the detected regions are involved in the centromeric region, joining the sister chromatids before anaphase.
染色体着丝粒由重复的DNA序列组成，在细胞分裂过程中协调染色单体的正确分离。我们通过研究两个仅在单个核苷酸位置不同的α卫星序列的原位分布，对人类13号和21号染色体的着丝粒进行了检测。这可以利用锁式探针实现，锁式探针是一种寡核苷酸，在识别靶标后可连接成环。通过监测来自两个分别针对不同序列变体的差异标记探针的信号，追踪了一个家族中13号和21号同源染色体的个体分离情况。重复基序在三个独立位点呈特征性排列，垂直于中期染色体的长度轴且左右对称，这表明检测到的区域中只有部分参与着丝粒区域，在后期之前连接姐妹染色单体。
