Genomic organization and chromosomal location of the human gene encoding the B-lymphocyte activation antigen B7

Annamalai Selvakumar, Bhaskara K. Mohanraj, Roger L. Eddy, Thomas B. Shows, Perrin C. White, Bo Dupont

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

The human B lymphocyte activation antigen B7 provides regulatory signals for T lymphocytes as a consequence of binding to its ligands CD28 and CTLA-4. The cDNA for B7 has previously been isolated and predicted to encode a type I membrane protein. The predicted polypeptide has a secretory signal peptide followed by two contiguous Ig-like domains, a hydrophobic transmembrane region and a short cytoplasmic tail. Here we report the exon-intron genomic organization of human B7 and the chromosomal location. The gene has six exons that span approximately 32 kilobases of DNA. Exon 1 is not translated and the second exon contains the initiation ATG codon and encodes a predicted signal peptide. This gene structure is characteristic for several eukaryotic genes with tissue-specific expression. The third and fourth exons correspond to two Ig-like domains whereas the fifth and sixth exons encode respectively the trans-membrane portion and the cytoplasmic tail. This close relationship between exons and functional domains is a characteristic feature of genes of the Ig superfamily. Cell surface expression of the B7 gene product has previously been mapped to human chromosome 12 by antibody reactivity with the B7-specific monoclonal antibody BB-1. We here demonstrate that the B7 gene is located to the q21-qter region of chromosome 3 by DNA blot analysis of human × rodent somatic cell hybrids.

Original languageEnglish (US)
Pages (from-to)175-181
Number of pages7
JournalImmunogenetics
Volume36
Issue number3
DOIs
StatePublished - May 1 1992

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ASJC Scopus subject areas

  • Immunology
  • Genetics

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