Molecular and serological analysis of polymorphisms in the murine major histocompatibility complex-encoded proteasome subunits, LMP-2 and LMP-7.
LMP-2 and LMP-7, gamma-interferon-inducible subunits of the 20S proteasome, play an important role in antigen processing. To define the molecular basis of their polymorphism, we sequenced Lmp-2 and Lmp-7 cDNA from nine different strains of mice. Three allelic variants of both LMP-2 and LMP-7 were found, but all of the polymorphism in LMP-7 is clustered near the carboxyl terminus of the molecule. We confirmed the nucleotide sequence changes at the protein level in both the unprocessed and processed forms of the molecules by analysis of specific anti-LMP-2, anti-LMP-7 and anti-proteasome immunoprecipitates on two-dimensional PAGE gels. Interestingly, a single amino acid change at position 272 between LMP-7b,d,q and LMP-7k,s,f,x,g7, cas4 from glycine to arginine dramatically affects its migration on SDS-PAGE gels, suggesting the possibility of allele-specific posttranslational modification.
Nandi
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Howard Hughes Medical Institute, University of Cincinnati, OH 45267-0524, USA.
Iyer
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Monaco
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D003546:Cysteine Endopeptidases; D018076:DNA, Complementary / Q000032:analysis; D008285:Major Histocompatibility Complex / Q000235:genetics; D051379:Mice; D016688:Mice, Inbred NOD; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics* / Q000276:immunology*; D010447:Peptide Hydrolases / Q000032:analysis; D011110:Polymorphism, Genetic / Q000235:genetics*; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000032:analysis*; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D009097:Multienzyme Complexes; D011506:Proteins; C071313:LMP-2 protein; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; C077436:LMP7 protein; D046988:Proteasome Endopeptidase Complex