Primary structural evidence that the H-2Dq region encodes at least three distinct gene products: Dq, Lq, and Rq.
Class I gene products D, L, and R encoded by the D region of the H-2q haplotype were isolated by sequential immunoprecipitation from Nonidet P-40 extracts of B10.AKM murine spleen cells. Primary structural comparisons of these molecules were made by tryptic peptide map analyses and radiochemical amino acid sequence determinations. Partial NH2-terminal radiosequence analyses of the peptides generated by CNBr cleavage of these three molecules defined the Rq molecule as a gene product that is distinct from the Dq and Lq molecules. Comparative tryptic peptide map analyses of [3H]arginine-, [3H]lysine-, or [3H]mannose-labeled molecules were performed to determine if the Dq and Lq molecules could be distinguished. The two molecules were identical in their [3H]lysine-labeled peptides (17 in common) and [3H]mannose-labeled glycopeptides but could be differentiated by their [3H]arginine-labeled peptides (18 of 21 in common). These results suggest an amino acid sequence homology of 99% or greater between the Dq and Lq molecules. These data therefore provide structural evidence for three D region gene products and suggest that their antigenic differences are not due to post-translational glycosylation differences. Thus, the D region of the H-2q haplotype may provide an example of a relatively recent class I gene duplication, indicating that these genes are in a dynamic state of evolution through expansion or contraction of the gene pool.
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D003488:Cyanogen Bromide; D005796:Genes; D006183:H-2 Antigens / Q000235:genetics*; D064532:Histocompatibility Antigen H-2D; D008285:Major Histocompatibility Complex; D051379:Mice; D008815:Mice, Inbred Strains; D010206:Papain; D010446:Peptide Fragments / Q000032:analysis; D014357:Trypsin
D000911:Antibodies, Monoclonal; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; D010446:Peptide Fragments; D014357:Trypsin; D010206:Papain; D003488:Cyanogen Bromide