THE MOUSE CD83 GENE - STRUCTURE, DOMAIN ORGANIZATION, AND CHROMOSOME LOCALIZATION

Human CD83 (hCD83) is a 45 000 M-r cell-surface protein expressed pred ominantly by dendritic lineage cells. In this report, the genomic locu s encoding mouse CD83 (Cd83) was isolated and the gene structure deter mined. The Cd83 gene spans similar to 19 kilobases (kb) and is compose d of five exons, with two exons encoding a single extracellular immuno globulin (Ig)-like domain. Mouse CD83 (mCD83) cDNAs were isolated by r everse transcriptase polymerase chain reaction of mouse RNA. Sequence determination revealed substantial conservation, with mCD83 and hCD83 sharing 63% amino acid identity. The transmembrane and cytoplasmic reg ions of CD83 were most highly conserved. Mouse CD83 mRNA of 2.4kb was abundantly expressed in spleen and brain, but could also be detected i n most tissues analyzed. These results suggest that in the mouse, as i n humans, widely distributed dendritic cells may express mCD83. Chromo some localization revealed that the Cd83 gene is present on mouse chro mosome 13 band A5, while the locus for the human gene (CD83) is locate d within a homologous region of human chromosome 6p23. Thus, the CD83 protein and gene appear to be well conserved during recent mammalian e volution. The isolation and characterization of the mCD83 cDNA and gen e provides important information and tools that will facilitate the st udy of CD83 and dendritic cell function in a mouse model system.