Sequence of the Cloned Gene for the Constant Region of Murine γ 2b Immunoglobulin Heavy Chain

The complete nucleotide sequence of the γ 2b constant region gene cloned from BALB/c liver DNA is reported. The sequence of approximately 1870 base pairs includes the 5' flanking, 3' untranslated, and 3' flanking regions and three introns. The Cγ 2b coding region is divided by these introns into four segments corresponding to the homology domains and hinge region of the protein. The introns separating the hinge from the C_H2 domain and the C_H2 from the C_H3 domain are small (106 and 119 base pairs). A larger intervening sequence of 314 base pairs separates the C_H1 and hinge regions. The stretch of DNA comprising this large intron plus the hinge shows a strong homology with the other C_H domains.