D2^d, a D-End class I gene: Tissue expression and alternative processing of the pre-mRNA

The H-2D region in the major histocompatibility complex (MHC) of the BALB/c mouse includes at least five class I genes: D^d, D2^d, D3^d, D4^d, and L^d. The pattern of expression and functions of the D2^d, D3^d, and D4^d genes are not known. To examine the expression of D2^d we obtained mouse L cells transfected with a wildtype D2^d gene or an exon shufled D2^d/D2^d/D^d gene that contained exons encoding the _α1 and _α2 domains of D2^d and the _α3 domain of H-2D^d. Analysis of the mRNA in transfected cells suggested that two forms of the message were generated at approximately equal abundance by alternative splicing. Several tissues were analyzed and shown to express both forms of the D2^d mRNA although the highest levels were found in lymphoid organs. Tumor lines also expressed D2^d mRNA but exhibited differing ratios of alternative versus normally spliced message. This ratio was also affected by treatment of cells with Con A supernatants that contain interferon or infection with vesicular stomatitis virus (VSV).