Evidence for a new murine immunoglobulin heavy chain variable region gene family

In the course of a previous study addressing autoantibody generation in murine models for generalized autoimmune disorders, we observed a nonfunctional immunoglobulin heavy chain transcript in a B cell hybridona from lupus-prone MRL-Mp-lpr/lpr mice. This transcript, the cDNA sequence of which is presented here, is of general interest for murine immunoglobulin genetics as it cannot be ascribed to any known heavy chain variable region gene (Vh) family by nucleic acid sequence homology criteria and, hence, may represent a new Vh gene family. The sequence showed about equal nucleotide similarity (70-73%) to 3 other Vh gene families (S107, J606, 7183) and less than 65 % similarity to members of the remaining 6 Vh gene families. Nucleic acid sequence comparisons with unpublished inmunoglobulin sequences uncovered a highly homologous (>95%) functional Vh transcript indicating that the suggested Vh gene family also encodes expressed antibody molecules.