Developmentally regulated expression of fibroblast growth factor receptor genes and splice variants by murine embryonic stem and embryonal carcinoma cells

Abstract

The expression of the four fibroblast growth factor receptor (FGF-R) genes was examined in murine embryonic stem (ES) cells, embryonal carcinoma (EC) cells, and their differentiated derivatives. FGF-R1 and FGF-R4 were found to be expressed constitutively in all samples examined. The expression of FGF-R2 and FGF-R3 was, however found to increase significantly upon differentiation of both ES and EC cells. Examination of splice variants of the third immunoglobulin domain (IgIII) of the extracellular region of the FGF-R2 revealed that whilst IgIIIc transcripts were expressed upon ES cell differentiation, IgIIIb transcripts (which confer specificity for the ligand FGF-7) were expressed in both ES cells and their differentiated progeny. FGF-R3 transcripts were also expressed in ES cells, but variant FGF-R3 transcripts containing the IgIIIb region were expressed upon differentiation. The findings suggest that the repertoire of FGF-R expression in embryonic cell types is developmentally regulated at the level of both gene expression, and alternative splicing and different members of the FGF-R family can exhibit distinct patterns of both gene and splice variant expression.