FIG. 1.

Schematic representation of the alternative splice variants of FGF-R2. (A) Diagram showing the relative positions of exons IIIb and IIIc in the context of a protein domain map of FGF-R2. Abbreviations denote the immunoglobulin-like domains (Ig 1 to Ig 3), transmembrane domain (TM), and both intracellular tyrosine kinase domains (TK). (B) The AT3 and DT3 cells splice to the mutually exclusive exons IIIc and IIIb, respectively. In DT3 cells, the previously described cis element, ISAR, functions both to activate IIIb inclusion and to repress IIIc inclusion. In AT3 cells, there has been no detected function for ISAR, and so IIIc is included regardless of the presence of ISAR.