Guardiola J, Maffei A, Carrel S, Accolla R S
International Institute of Genetics and Biophysics, CNR, Napoli, Italy.
Immunogenetics. 1988;27(1):12-8. doi: 10.1007/BF00404438.
Restriction fragment analysis has been applied to genomic DNA extracted from human tumor cell lines. Polymorphic restriction fragments encompassing the HLA-DQ alpha gene were observed upon digestion with Bgl II, Eco RI, and Hind III. Analysis of these polymorphic fragments (or allogenotopes) showed that for each restriction enzyme a series of three differently sized allogenotopes existed. Clusters of cosegregating allogenotopes belonging to the different allelic series defined three different allogenotypes. Each allogenotype exhibited a distinctive restriction map generated by digestion with five restriction enzymes. Comparison of these restriction maps showed that generation of the polymorphisms observed at the HLA-DQ alpha region in these sets of cell lines is not caused by a single event. In some B- and T-lymphoma cell lines a fourth allogenotype was found. The restriction site map of genomic DNA from these cell lines suggested that the latter distribution of restriction enzyme sites was most probably generated by recombination between two of the previously observed allogenotypes at a crossover site(s) adjacent to the HLA-DQ alpha gene.
限制性片段分析已应用于从人类肿瘤细胞系中提取的基因组DNA。在用Bgl II、Eco RI和Hind III消化后，观察到包含HLA-DQα基因的多态性限制性片段。对这些多态性片段（或同种异型表位）的分析表明，对于每种限制酶，存在一系列三种不同大小的同种异型表位。属于不同等位基因系列的共分离同种异型表位簇定义了三种不同的同种异型基因型。每种同种异型基因型都表现出由五种限制酶消化产生的独特限制性图谱。这些限制性图谱的比较表明，在这些细胞系组中HLA-DQα区域观察到的多态性的产生不是由单一事件引起的。在一些B细胞和T细胞淋巴瘤细胞系中发现了第四种同种异型基因型。来自这些细胞系的基因组DNA的限制性酶切位点图谱表明，后者限制性酶切位点的分布很可能是由先前观察到的两种同种异型基因型在与HLA-DQα基因相邻的一个或多个交叉位点处重组产生的。
