Genomic organization and chromosome location of the rat CD3ζ locus (Cd3z)

The structure and pattern of expression of the CD3ζ chain have apparently been conserved throughout mammalian evolution. The organization of the rat CD3ζ locus was determined by genomic cloning and nucleotide sequencing. Most of the rat CD3ζ coding region was similar to mouse and human CD3ζ sequences. Whereas the 3' region involving alternative splicing was relatively well conserved at the nucleotide level, the deduced amino acid sequences were different in rats, mice and humans due to the presence of deletion and insertion mutations. Alternative splicing products of the CD3ζ locus, such as CD3η, CD3θ and CD3τ which have been reported for mice, were not expressed by rat T cells. By using fluorescence in situ hybridization, we have localized rat CD3ζ to chromosome 13q22→q23.