Structure of the genes encoding the CD19 antigen of human and mouse B lymphocytes

CD19 is a B lymphocyte cell-surface marker that is expressed early during pre-B-cell differentiation with expression persisting until terminal differentiation into palsma cells. CD19 is a member of Ig gnee superfamily with two extreacellular Ig-like domains separated amino acid cytoplasmic domain. In this study, Southern blot analysis revelaed that the human and mouse CD19 genes were compact single copy genes. Both the human and mouse CD19 genes were isolated and the nucleotide sequences flanking each exon were determined. Both genes were composed of 15 exons and spanned 8 kilobases (kb) of DNA in human and 6 kb in mouse. The positions of exon-intron boundaries were identical between human and mouse and correlated with the putative functional domains of the CD19 protein. The 200 bp region 5 of the putative translation initiation AUG codon as well conserved in sequence between human and mouse and contained potential trasncription regulatory elements. In addition, the 3 untranslated regions (UT) of the CD19 genes following the termination codon were conservedf in sequence. The high level conservation of nucleotide sequences between species in all exons and 5 and 3 UT suggests that expression of the CD19 gene may be regulated in a similar fashion in human and mouse.The nucleotide sequence database reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers: human CD19 gnee, M62544 to M62550; mouse CD19 gene, M62551 to M62553.