CTLA-4 and CD28 activated lymphocyte molecules are closely related in both mouse and human as to sequence, message expression, gene structure, and chromosomal location.

摘要: CD28, initially detected on human T lymphocytes with the help of antibodies, and CTLA-4, obtained by reverse genetics through its preferential expression in mouse activated cells, are both single-V domain members Ig superfamily. Early work showed a relationship between these two molecules, which we wished to further document, particular because growing realization functional importance CD28 some cell activation pathways. Isolation analysis CTLA-4 gene that share same overall intron/exon organization. The nucleic acid sequence homology exons was found extend across molecules species, whereas 5' 3' flanking regions exhibited species but not molecules. Message only cells and, thus, shares lymphoid tissue distribution, although apparently broader for latter. Two main transcripts about 1.8 0.8 kb were detected, smaller may derive, as reported from use an alternate degenerated polyadenylation signal sequence. data allowed direct comparison four putative complete protein sequences human, showing striking homologies, especially stretches (such MYPPPY hexamer hinge region) conserved species. localized chromosome 1 band C situ hybridization three different radioactive probes, indicating, together previous data, genes map chromosomal region human. Thus, be strikingly similar most respects, terms structure, sequence, expression, location, furthermore strongly suggesting their products duplication event raising possibility homologies corresponding proteins.