Carroll M C, Belt T, Palsdottir A, Porter R R
Philos Trans R Soc Lond B Biol Sci. 1984 Sep 6;306(1129):379-88. doi: 10.1098/rstb.1984.0098.
This 200 000 Mr serum protein is coded for by at least two separate loci, C4A and C4B, which map in the HLA Class III region on chromosome 6 in man. Both loci are highly polymorphic with more than 30 alleles, including null alleles assigned to the two loci. The complete nucleotide sequence of a full length C4A cDNA clone and a substantial part of a C4b cDNA clone has shown class differences which can be used to synthesize nucleotide probes specific for C4A and C4B. Three C4 loci of approximately 16 kilobases each spaced by 10 kilobases have been identified in DNA from one individual and aligned 30 kilobases from the factor B gene by overlapping cloned genomic fragments from a cosmid library. Characterization of these genes by restriction mapping, nucleotide sequence analysis and hybridization with C4A and C4B specific synthetic oligonucleotides show that these genes are very similar.
这种200 000 Mr血清蛋白由至少两个独立的基因座C4A和C4B编码，它们定位于人类6号染色体上的HLA III类区域。两个基因座都具有高度多态性，有30多个等位基因，包括分配给这两个基因座的无效等位基因。一个全长C4A cDNA克隆和一个C4b cDNA克隆的大部分的完整核苷酸序列显示出类别差异，可用于合成对C4A和C4B特异的核苷酸探针。通过来自黏粒文库的重叠克隆基因组片段，在一个个体的DNA中鉴定出了三个每个约16千碱基且间隔10千碱基的C4基因座，并将其与因子B基因的30千碱基进行了比对。通过限制性图谱分析、核苷酸序列分析以及与C4A和C4B特异的合成寡核苷酸杂交对这些基因进行表征，结果表明这些基因非常相似。
