Genetic mechanisms of the complement deficiency associated with immune abnormalities

1)为了深入了解人C3缺乏的遗传机制，采用Northern和Southern印迹法对提取的外周血mRNA和DNA进行分析。此外，从患者DNA中分离出16kb长的C3基因，并进行了广泛的结构和功能分析。综合结果表明，该患者的C3缺陷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单倍型的小鼠品系总是低C4产素。对这些小鼠品系的C4 mRNA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200bp的异常插入。随后的结构。对低产C4的C4基因进行分析发现，该基因第13个内含子上有类似于反转录转座子的B2序列插入，这可能是C4转录物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.