Perl A, Divincenzo J P, Gergely P, Condemi J J, Abraham G N
Department of Medicine, University of Rochester Medical Center, New York 14642.
Immunology. 1989 May;67(1):135-8.
Southern blot analysis with human T-cell receptor (TcR) beta-chain specific cDNA probes revealed two novel allelic forms of the TcR beta-2 gene locus. Three different genotypes were noted based on the presence of polymorphic KpnI restriction fragments: I, 5.7 kb fragment only; II, 3.9 kb and 1.8 kb fragments only; III, all three polymorphic fragments. This hybridization pattern suggested that the presence or absence of a polymorphic KpnI site within the 5.7 kb fragment defines the two different allelic forms of the TcR beta chain locus. By Southern blot analysis of genomic DNA from T-cell lines with deleted C-beta-1 regions and computer-assisted restriction site mapping of germline and cDNA sequences of the C-beta-2 locus, the polymorphic KpnI site was localized at 24 bp 5' to the third exon of the C-beta-2 gene. It was determined that the polymorphic KpnI site and the earlier described polymorphic BglII site located 5' to the C-beta-2 gene are not co-inherited. No difference was noted in distribution of the KpnI genotypes and allelic frequencies between 26 normal individuals and 22 patients with systemic lupus erythematosus. However, this newly characterized polymorphism of the TcR locus should provide a useful tool to analyse the role of inherited genetic variations in the function of T lymphocytes under normal and pathological conditions.
用人T细胞受体（TcR）β链特异性cDNA探针进行的Southern印迹分析揭示了TcRβ-2基因座的两种新的等位基因形式。根据多态性KpnI限制性片段的存在情况，观察到三种不同的基因型：I型，仅5.7 kb片段；II型，仅3.9 kb和1.8 kb片段；III型，所有三种多态性片段。这种杂交模式表明，5.7 kb片段内多态性KpnI位点的存在与否定义了TcRβ链基因座的两种不同等位基因形式。通过对C-β-1区域缺失的T细胞系的基因组DNA进行Southern印迹分析，以及对C-β-2基因座的种系和cDNA序列进行计算机辅助限制性位点定位，多态性KpnI位点定位在C-β-2基因第三个外显子5'端24 bp处。已确定多态性KpnI位点与先前描述的位于C-β-2基因5'端的多态性BglII位点并非共遗传。在26名正常个体和22名系统性红斑狼疮患者之间，未观察到KpnI基因型分布和等位基因频率的差异。然而，这种新鉴定的TcR基因座多态性应为分析正常和病理条件下遗传变异在T淋巴细胞功能中的作用提供一个有用的工具。
