Genetic mechanisms of the complement deficiency associated with immune abnormalities

1)为了深入了解人类C3缺乏症的遗传机制，从人外周血中提取的mRNA和DNA进行了Northern和Southern杂交分析。此外，从患者DNA中分离出16kb的C3基因，并对其进行了广泛的结构和功能分析。综合结果表明，该患者的C3缺乏状态是由转录后和翻译前水平的遗传异常引起的。2)H-2_k单倍型小鼠品系总是低C4产生。对这些品系的C4基因进行分析，发现存在由B2重复序列和部分内含子序列组成的异常的200bp插入片段。随后的结构。对分离自低C4产生菌的C4基因的分析表明，该基因第13内含子上存在B2序列的反转录转座子样插入，这可能是C4转录本的RNA剪接异常的原因。

1) In order to gain insight info the genetic mechanism of human C3 deficiency, mRNA and DNA extracted from peripheral blood were analyzed by Northern and Southern blotting. Furthermore, C3 gene of 16kb long was isolated from the patient DNA and subjected to extensive structural and functional analyzes. The combined results showed that the C3 deficient state of this patient is caused by genetic irregularities at the posttranscriptional and pretranslational level.2) Mouse strains of H-2_k haplotype are invariably low C4 producers. Analysis of C4 mRNA from these mouse strains'revealed the presence of abnormal 200bp insert consisting of B2 repetitive sequence and part of intronic sequence. Subsequent structural. analyses of C4 genes isolated from low C4 producers showed the retrotransposon-like insertion of B2 sequent in the 13th intron of the gene, which probably accounts for the aberrant RNA splicing of the C4 transcript.