Mutual homology of mouse immunoglobulin gamma-chain gene sequences.
We have assessed the relative homology of mouse immunoglobulin heavy-chain gene sequence using complementary DNAs (cDNAs) synthesized against gamma-chain mRNAs (gamma 1, gamma 2a, gamma 2b, and gamma 3) purified from mouse myelomas. cDNAs complementary to the gamma-chain mRNAs did not cross-hybridize with the mu- and alpha-chain mRNAs, whereas they cross-hybridized to significant extents (22--66%) with the gamma-chain mRNAs of other subclasses. The heterologous hybrids formed, however, melt at 5--13 degrees C lower temperatures as compared to the homologous hybrids, indicating that significant portions of the heterologous hybrids are mismatched. The rates of the cross-hybridization reactions are 2- to 17-fold slower than those of the homologous hybridization reactions. Therefore, the gamma-chain gene sequences of four subclasses share a part of homology with each other, but they are different enough to be measured separately. Cross-hybridization analysis indicate that the gamma 2a and gamma 2b genes are the most closely related, while the gamma 1 and gamma 3 genes are the least related among the gamma subclass genes.
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D005796:Genes; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis*; D007142:Immunoglobulin gamma-Chains / Q000096:biosynthesis*; D007700:Kinetics; D051379:Mice; D009101:Multiple Myeloma / Q000378:metabolism; D009374:Neoplasms, Experimental / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis; D014158:Transcription, Genetic
D007143:Immunoglobulin Heavy Chains; D007142:Immunoglobulin gamma-Chains; D004247:DNA