The reference OMIM entry for this protein is 217070

Complement component 7; c7

DESCRIPTION

C7 is a single-chain plasma glycoprotein involved in the cytolytic phase of complement activation (Hobart et al., 1995). Mutations in the C7 gene cause C7 deficiency (610102), a defect associated with increased susceptibility to neisserial recurrent infections (Barroso et al., 2004).

CLONING

By screening a liver cDNA library, DiScipio et al. (1988) obtained a full-length cDNA encoding C7. The deduced 843-amino acid protein has a 22-amino acid N-terminal leader sequence, 56 cysteines predicted to form 28 disulfide bonds, and 2 N-glycosylation sites.

GENE STRUCTURE

Hobart et al. (1995) determined that the C7 gene contains 18 exons and spans 80 kb.

MAPPING

Hobart et al. (1978) identified 3 structural forms of C7, concluded they are the products of 3 codominant alleles at an autosomal locus, and found that the C6 and C7 loci are closely linked to each other but not to the HLA complex. By Southern blot analysis of hybrid cell DNAs using cDNA probes, Jeremiah et al. (1989, 1990) demonstrated that the human C6 and C7 genes are located on chromosome 5. See Coto et al. (1991) for linkage information indicating that C6, C7, and C9 are closely situated; C9 was mapped to 5p13. Eldridge et al. (1983) found 2 closely linked C7 loci (7C1 and 7C2) in the dog. Both are closely linked to C6 and are not close to MHC. In the domestic cat, as in man, there is a single C7 locus.

MOLECULAR GENETICS

Nakamura et al. (1984) identified common variants of C7 in Japanese. Washio et al. (1986) described polymorphism of C7 in Japanese and described a 'new' rare variant. No significant association was found between C6 and C7 alleles to suggest linkage disequilibrium. Washio et al. (1986) pointed out that Japanese show a higher degree of polymorphism of both C6 and C7 than do Caucasians. Using an ELISA method with a monoclonal antibody, Wurzner et al. (1990) demonstrated a new C7 allele which they referred to as C7*9. A gene frequency of 0.21 was estimated. With conventional techniques, C7*9 was included in the frequency of C7*1. Wurzner et al. (1992) described a new protein polymorphism detected by a monoclonal antibody. Alvarez et al. (1995) described studies of 3 families, in each of which 2 sibs suffered from recurrent Neisseria meningitidis infection and were demonstrably homozygous for a C7*Q0 'silent allele.' The haplotypes for RFLPs at the 3 closely linked C6, C7, and C9 genes were defined, allowing for the detection of carriers among asymptomatic relatives. Seven mutations in the C7 gene were identified by Fernie and Hobart (1998): 3 missense, 2 single-nucleotide deletions, and 2 defects of the 5-prime splice donor site. Data on gene frequencies of allelic variants were tabulated by Roychoudhury and Nei (1988). For a discussion of a possible association between variation in the C7 gene and multiple sclerosis, see MS3 (612595). ... More on the omim web site

Subscribe to this protein entry history

Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).

Oct. 19, 2018: Protein entry updated
Automatic update: OMIM entry 217070 was added.