Choo K H, Vissel B, Brown R, Filby R G, Earle E
Murdoch Institute for Research into Birth Defects, Royal Children's Hospital, Parkville, Victoria, Australia.
Nucleic Acids Res. 1988 Feb 25;16(4):1273-84. doi: 10.1093/nar/16.4.1273.
We report a new subfamily of alpha satellite DNA (pTRA-2) which is found on all the human acrocentric chromosomes. The alphoid nature of the cloned DNA was established by partial sequencing. Southern analysis of restriction enzyme-digested DNA fragments from mouse/human hybrid cells containing only human chromosome 21 showed that the predominant higher-order repeating unit for pTRA-2 is a 3.9 kb structure. Analysis of a "consensus" in situ hybridisation profile derived from 13 normal individuals revealed the localisation of 73% of all centromeric autoradiographic grains over the five acrocentric chromosomes, with the following distribution: 20.4%, 21.5%, 17.1%, 7.3% and 6.5% on chromosomes 13, 14, 21, 15 and 22 respectively. An average of 1.4% of grains was found on the centromere of each of the remaining 19 nonacrocentric chromosomes. These results indicate the presence of a common subfamily of alpha satellite DNA on the five acrocentric chromosomes and suggest an evolutionary process consistent with recombination exchange of sequences between the nonhomologues. The results further suggests that such exchanges are more selective for chromosomes 13, 14 and 21 than for chromosomes 15 and 22. The possible role of centromeric alpha satellite DNA in the aetiology of 13q14q and 14q21q Robertsonian translocations involving the common and nonrandom association of chromosomes 13 and 14, and 14 and 21 is discussed.
我们报道了一个新的α卫星DNA亚家族（pTRA - 2），它存在于所有人类近端着丝粒染色体上。通过部分测序确定了克隆DNA的α卫星性质。对仅含人类21号染色体的小鼠/人类杂交细胞经限制性内切酶消化的DNA片段进行Southern分析表明，pTRA - 2的主要高阶重复单元是一个3.9 kb的结构。对13名正常个体的“一致性”原位杂交图谱分析显示，在五条近端着丝粒染色体上，所有着丝粒放射自显影片颗粒的73%定位如下：13号、14号、21号、15号和22号染色体上分别为20.4%、21.5%、17.1%、7.3%和6.5%。在其余19条非近端着丝粒染色体的每条着丝粒上平均发现1.4%的颗粒。这些结果表明在五条近端着丝粒染色体上存在一个共同的α卫星DNA亚家族，并提示了一个与非同源染色体间序列重组交换相一致的进化过程。结果还表明，这种交换对13号、14号和21号染色体的选择性高于15号和22号染色体。本文讨论了着丝粒α卫星DNA在涉及13号与14号以及14号与21号染色体常见且非随机关联的13q14q和14q21q罗伯逊易位病因学中的可能作用。
