Complement Component 1, Q Subcomponent B (C1qB)

C1q, the first subcomponent of C1, has a complicated 18-chain structure: 6 A, 6 B, and 6 C chains. Each chain has a stretch of about 80 amino acids with the collagenous triplet Gly-X-Y where X and Y can include hydroxyproline and hydroxylysine. The A, B, and C chains combine to form 6 heteromeric triple helices in the collagenous regions of the chains. Using a cDNA probe to the B chain of C1q, Solomon et al. (1985) assigned the gene to chromosome 1 in somatic cell hybrids. A hybrid containing 1p, but no 1q, allowed them to localize the gene to 1p.Hybridization of cDNA probes to a hybrid cell line containing the derived X chromosome from an X;1(q21.2;p34) translocation described in a female patient with Duchenne muscular dystrophy (Lindenbaum et al., 1979; Boyd et al., 1988) showed that the A and B genes are located in the region 1p36.3-p34.1.