D2d, 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: Dd, D2d, D3d, D4d, and Ld. The pattern of expression and functions of the D2d, D3d, and D4d genes are not known. To examine the expression of D2d we obtained mouse L cells transfected with a wildtype D2d gene or an exon shufled D2d/D2d/Dd gene that contained exons encoding the alpha 1 and alpha 2 domains of D2d and the alpha 3 domain of H-2Dd. 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 D2d mRNA although the highest levels were found in lymphoid organs. Tumor lines also expressed D2d 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).