The mouse Cd83 gene: structure, domain organization, and chromosome localization.

Human CD83 (hCD83) is a 45 000 Mr cell-surface protein expressed predominantly by dendritic lineage cells. In this report, the genomic locus encoding mouse CD83 (Cd83) was isolated and the gene structure determined. The Cd83 gene spans approximately 19 kilobases (kb) and is composed of five exons, with two exons encoding a single extracellular immunoglobulin (Ig)-like domain. Mouse CD83 (mCD83) cDNAs were isolated by reverse 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 regions of CD83 were most highly conserved. Mouse CD83 mRNA of 2.4 kb was abundantly expressed in spleen and brain, but could also be detected in most tissues analyzed. These results suggest that in the mouse, as in humans, widely distributed dendritic cells may express mCD83. Chromosome localization revealed that the Cd83 gene is present on mouse chromosome 13 band A5, while the locus for the human gene (CD83) is located within a homologous region of human chromosome 6p23. Thus, the CD83 protein and gene appear to be well conserved during recent mammalian evolution. The isolation and characterization of the mCD83 cDNA and gene provides important information and tools that will facilitate the study of CD83 and dendritic cell function in a mouse model system.