Complete sequence of an HLA-dR beta chain deduced from a cDNA clone and identification of multiple non-allelic DR beta chain genes.
AUTOR(ES)
Long, E O
RESUMO
At least three polymorphic class II antigens are encoded in the human major histocompatibility complex (HLA): DR, DC and SB. cDNA clones encoding beta chains of HLA-DR antigen, derived from mRNA of a heterozygous B-cell line, were isolated and could be divided into four subsets, clearly distinct from cDNA clones encoding DC beta chains. Therefore, at least two non-allelic DR beta chain genes exist. The complete sequence of one of the DR beta chain cDNA clones is presented. It defines a putative signal sequence, two extracellular domains, a trans-membrane region and a cytoplasmic tail. Comparison with a DC beta chain cDNA clone revealed a homology of 70% between the two beta chains and that the two genes diverged under relatively little selective pressure. A set of amino acids conserved in immunoglobulin molecules was found to be identical in both DR and DC beta chains. Comparison of the DR beta chain sequence with the amino acid sequence of another DR beta chain revealed a homology of 87% and that most differences are single amino acid substitutions. Allelic polymorphism in DR beta chains has probably not arisen by changes in long blocks of sequence.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=555145Documentos Relacionados
- Isolation and identification of a cDNA clone corresponding to an HLA-DR antigen beta chain.
- Evolutionary and genetic implications of sequence variation in two nonallelic HLA-DR beta-chain cDNA sequences.
- cDNA clones coding for the heavy chain of human HLA-DR antigen.
- cDNA clone for the heavy chain of the human B cell alloantigen DC1: strong sequence homology to the HLA-DR heavy chain.
- Isolation of cDNA clones encoding HLA-DR alpha chains.