Identification of D segments of immunoglobulin heavy-chain genes and their rearrangement in T lymphocytes

Abstract
The finding that the diversity (D) and joining (JH) but not the variable (VH) DNA segments of mouse Ig heavy-chain genes are joined in the DNA of some cloned cytolytic T cells, led to identification and sequencing of 3 different D DNA segments. Two segments identified on the embryo DNA carry on both the 5'' and 3'' sides 2 sets of characteristic sequences separated by a 12-base pair spacer, which were implicated as recognition signals for a recombinase. The 3rd segment, identified in a form joined with a JH DNA segment in a T cell, carries the recognition signal on the 5'' side. The 12/23-base pair model for somatic generation of Ig V genes is supported and the possibility that the cytolytic T cells use assembled VH, D and JH sequences to encode their antigen receptors is excluded.