|Blood Group Antigen Gene Mutation Database|
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Ok Blood Group System
Gene locus - BSG (basigin)
The Oka antigen was described in 1979 and named after the family of the patient. The OK blood group system was established in 1999. To date, the null phenotype (Ok(a-)) has been found in eight Japanese families only. Therefore the incidence of the Oka antigen in the world populations seems to be close to 100%.
The antigen for the OK blood group system is known by several names: Basigin (BSG), EMMPRIN (extracellular matrix metalloprotein inducer), M6 leukocyte activation antigen, and CD147. It is a member of the immunoglobulin superfamily. It is a single pass type I glycoprotein, of 269 amino acids (predicted) with three potential N-glycosylation sites. The mature protein is 259 amino acids long and the size on SDS gels is 35-60 Kd . The extracellular domain, of 187 amino acids contains two immunoglobulin-related domains. The BSG gene is organized in 7 exons whose total length is 1.8kb.
Function of proteins
It is thought that Basigin upon binding to an unknown ligand on tumor fibroblasts, stimulates the production of collagenase and other extracellular matrix metalloproteinases, thereby enhancing cell invasion and metastases.
Expressed in embryonic and adult tissues. Epithelium in kidney cortex and medulla, liver, acinar cells of the pancreas, trachea, cervix, testes, colon, skin, smooth muscle, neural cells, forebrain, cerebellum
Expression on granulocytes is increased in rheumatoid and reactive arthritis. May be involved in tumor metastases.
The polymorphic forms of Basigin, the antigen of the OK blood group system, have been shown to occur in eight Japanese families, whose red cells exhibit the Ok(a-) phenotype. Mutations were established in DNA from three Japanese donors: two sisters and an unrelated individual (Spring et al.).
In the list of alleles, the sequence acc. no. L10240 is taken as reference (codon one for M starts at nt. 15); it is the sequence of Oka EMPIRIN (same as Basigin) mRNA.
Other database IDs and links
Marion E. Reid and Christine Lomas-Francis, Immunohematology, New York Blood Center, 310 East 67 St., New York, N.Y., 10021
Contributors for specific alleles are listed with the alleles.
Updated 2008-12-17 20:02:11.813