Davis R E, Meuth M
Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Hertfordshire, U.K.
Somat Cell Mol Genet. 1994 Jul;20(4):287-300. doi: 10.1007/BF02254718.
The nature of multilocus deletions eliminating the adenine phosphoribosyltransferase (aprt) gene was analyzed in a CHO cell strain heterozygous for this locus. These deletions arose at a high frequency, spanning an estimated average length of 4250 kb. To detect breakpoints participating in their formation, a 200-kb region surrounding aprt was screened for novel fragments. Seven novel fragments were detected, five of which were clustered around the aprt gene itself. Despite the existence of at least eight Alu-equivalent repeats in this region, no breakpoints fell within these elements. Two deletions were characterized in more detail by cloning and sequencing their junction fragments. The novel DNA detected at one junction was unique, whereas that situated at the junction of the other deletion was of a repetitive nature, consisting of a truncated intracisternal-A particle gene. The contrasting nature of these junctions may imply that multilocus deletions of aprt can occur by one of several mechanisms.
在一个对此基因座杂合的中国仓鼠卵巢（CHO）细胞株中，分析了消除腺嘌呤磷酸核糖转移酶（aprt）基因的多位点缺失的性质。这些缺失以高频率出现，估计平均长度跨越4250 kb。为了检测参与其形成的断点，对围绕aprt的一个200 kb区域进行筛选以寻找新片段。检测到七个新片段，其中五个聚集在aprt基因本身周围。尽管该区域存在至少八个Alu等效重复序列，但没有断点位于这些元件内。通过克隆和测序它们的连接片段，对两个缺失进行了更详细的表征。在一个连接处检测到的新DNA是独特的，而位于另一个缺失连接处的DNA具有重复性质，由一个截短的脑内A颗粒基因组成。这些连接的不同性质可能意味着aprt的多位点缺失可以通过几种机制之一发生。
