mRNA variants encoding multiple forms of the high-affinity IgE receptor alpha subunit in transformed and nontransformed mast cells

Multiple mRNA species encoding several predicted forms of the high-affinity IgE receptor α subunit (FcεRI-α) have been previously characterized from rat basophilic leukemia cells. Using the polymerase chain reaction procedure, we have extended these findings to show that one FcεRI-α mRNA variant, characterized by a 163-bp deletion within the coding sequence, exists in normal rat connective tissue mast cells as well as in both transformed and non transformed murine mast cell lines. In addition, a partial murine FcεRI-α genomic clone, spanning the internal-deletion sequence, has been identified, and from analysis of this sequence a mechanism of alternative pre-mRNA splicing is proposed. Finally, mRNA variants have been translated in a cell-free system and the protein products partially characterized.