Heavy chain genes of rabbit IgG: isolation of a cDNA encoding gamma heavy chain and identification of two genomic C gamma genes.

A cDNA library was constructed by using rabbit spleen poly(A)+RNA as template, and from this library was isolated a cDNA clone, p2a2, that encodes 179 amino acids of the heavy chain of rabbit IgG. The nucleotide sequence of p2a2 showed that it encodes the COOH-terminal eight amino acids of the CH1 domain, the hinge region, the CH2 domain, and the NH2-terminal half of the CH3 domain of C gamma. Southern blot hybridization analysis of rabbit sperm DNA showed that two EcoRI fragments hybridized strongly with the C gamma cDNA. The p2a2 cDNA was used as a probe to isolate recombinant Charon 4A phage clones containing C gamma sequences from a genomic library of rabbit liver DNA. Two distinct DNA segments were identified by restriction mapping and hybridization analysis, suggesting that the haploid rabbit genome may contain two different C gamma genes.