Rearrangement of immunoglobulin gamma 1-chain gene and mechanism for heavy-chain class switch.

Abstract
Cloning and nucleotide sequence determination suggest that the rearranged .gamma.1-chain gene in a .gamma.1-chain-producing [mouse] myeloma appears to be formed by the recombination between the 5'' flanking regions of the .gamma.1- and .mu.-chain genes of undifferentiated cells. The recombination site is distinct from the putative J [joining] region and is a novel region called the S region. The previous model, which explains H-chain class switching by 2 or more successive recombination events, was extended.