CD19 MAPS TO A REGION OF CONSERVATION BETWEEN HUMAN CHROMOSOME-16 ANDMOUSE CHROMOSOME-7

CD19 is a B lymphocyte cell surface protein expressed from the earlies t stages of B lymphocyte development until their terminal differentiat ion into plasma cells. In this report the human CD19 gene (hCD19) was localized to band p11.2 on the proximal short arm of chromosome 16 by in situ hybridization to metaphase chromosomes, using hCD19 cDNA as pr obe. hCD19 gene localization was confirmed by polymerase chain reactio n based analysis with hCD19-specific primers, using a panel of human/h amster somatic cell hybrid DNA as templates. The mouse CD19 gene (mCd1 9) was mapped to bands F3-F4 of chromosome 7 by in situ hybridization to metaphase chromosomes, using a mCD19 cDNA probe. Segregation analys is of nucleotide sequence polymorphisms in interspecific backcross pro geny revealed linkage of mCd19 with hemoglobin beta (Hbb), Int-2, and H19, other loci previously mapped to the same region of mouse chromoso me 7, confirming the localization of mCd19 to this region. The order o f these loci was determined to be centromere - Hbb - mCd19 - H19 - Int -2 - telomere. The genetic distances between the loci examined, calcul ated from the recombination frequencies, suggested that mCd19 was loca ted centrally between Hbb and H19. This region of mouse chromosome 7 i s homologous to the region of human chromosome 16 to which the hCD19 g ene maps. Multiple genes with a lymphocyte-related function also map t o this conserved region including genes encoding the IL-4 receptor, CD 11a, CD11b, CD11c, CD43 (leukosialin), and protein kinase C beta polyp eptide.