An unequal crossover between the RCCX modules of the human MHC leading to the presence of a CYP21B gene and a tenascin TNXB/TNXA-RP2 recombinant between C4A and C4B genes in a patient with juvenile rheumatoid arthritis.
An unequal crossover between the RCCX modules of the human MHC leading to the presence of a CYP21B gene and a tenascin TNXB/TNXA-RP2 recombinant between C4A and C4B genes in a patient with juvenile rheumatoid arthritis.
复制标题
人类 MHC RCCX 模块之间的不等交叉导致幼年类风湿性关节炎患者的 C4A 和 C4B 基因之间存在 CYP21B 基因和生腱蛋白 TNXB/TNXA-RP2 重组体。
DOI：
10.1159/000019099
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Yu,CY
中科院分区：
文献类型：
--
作者：
Rupert,KL;Rennebohm,RM;Yu,CY
人类MHC III类区域的RCCX模块由四个串联排列的基因组成：RP、补体C4、类固醇21-羟化酶（CYP 21）和腱生蛋白X（TNX）。RCCX模块的数量和基因的变化可能导致遗传和/或自身免疫性疾病。采用限制性片段长度多态性（RFLP）分析方法，对幼年类风湿关节炎（JRA）患者的RCCX基因进行了研究。在JRA患者L1中，RFLP分析表明存在含有C4 A长基因和C4 B短基因的双模RCCX结构，但缺少通常位于C4 A和C4 B基因之间的CYP 21 A和TNXA基因的标记。对CYP 21-TNX-RP 2基因的7.5kb片段进行了克隆和测序，结果表明，RCCX双模块染色体的TNXA与RCCX单模块染色体的TNXB发生了基因重组。这种重组导致了一种新的MHC单倍型，其中CYP 21 B基因和TNXB/TNXA-RP 2重组体位于两个C4基因之间。断裂点区域的阐明为RCCX模块化变异导致的MHC III类基因区域的不稳定性提供了进一步的证据。
The RCCX module of the human MHC class III region is comprised of four genes arranged in tandem:RP,complementC4,steroid 21-hydroxylase(CYP21),and tenascin X(TNX).Variations in the number and genes of the RCCX modules may lead to genetic and/or autoimmune diseases. Restriction fragment length polymorphism (RFLP) analysis was utilized to determine the RCCX modular variation in patients with juvenile rheumatoid arthritis (JRA). In JRA patient L1, RFLP analysis suggested the presence of a bimodular RCCX structure containing bothC4A longandC4B shortgenes, yet missing the markers for theCYP21AandTNXAgenes usually located between theC4AandC4Bgenes. The 7.5-kb genomic fragment spanning theCYP21-TNX-RP2genes was cloned and sequenced, revealing that a genetic recombination occurred betweenTNXAof a bimodular RCCX chromosome andTNXBof a monomodular RCCX chromosome. This recombination results in a new MHC haplotype with aCYP21Bgene and aTNXB/TNXA-RP2recombinant between the twoC4genes. Elucidation of the breakpoint region provides further evidence for the instability of the MHC class III gene region as a result of the RCCX modular variation.