Molecular characterization of rat NKR-P2, a lectin-like receptor expressed by NK cells and resting T cells

The gene for a rat NK lectin-like receptor (NKLLR), named NKR-P2, has beencloned and characterized. Sequence analysis shows that it represents theorthologue of human NKG2D and that the two molecules form a distinct NKLLRfamily, no more related to NKG2A/B, -C or -E than to other NKLLR families.Nkrp2 is a single-copy gene containing seven introns, mapping to the rat NKgene complex. Rat NKR-P2 differs from the human orthologue in that itscytoplasmic tail contains 13 additional amino acids, encoded by a separateexon. Splice variants lacking this exon were not detected in T cells or NKcells. NKR-P2 is strongly expressed by NK cells. In contrast to otherNKLLR, it is also strongly expressed by resting thoracic duct CD4+ and CD8+T cells, but not by thymocytes or other hemopoietic cells.