Developmental expression of splicing variants of fibroblast growth factor receptor 3 (FGFR3) in mouse.

A characteristic feature of the fibroblast growth factor receptor (FGFR) family is the structural diversity generated by alternative splicing. The FGFR3 gene encodes two splice variants because of the mutually exclusive use of the exons IIIb and IIIc. In the present study we examined the expression of the two different splice forms IIIb and IIIc of FGFR3 in developing mouse embryos (12 days p.c., 14 days p.c., 20 days p.c.). The overall level of the IIIc exon splice product surpassed that of the IIIb exon form. The IIIc mRNA was detected in the developing brain and in the spinal cord. Outside the nervous system very strong expression was observed in the vertebra and in all other bony structures. In contrast, the IIIb splice form was restricted to epithelial structures with no expression detected in the central nervous system and bone.