FIBROBLAST GROWTH FACTOR-I RECEPTOR MESSENGER-RNA EXPRESSION IN CORNEAL CELLS

The polymerase chain reaction (PCR) and hot-blotting methods were used to identify fibroblast growth factor (FGF) receptor-1-specific messen ger ribonucleic acid (mRNA) sequences in cDNA samples prepared from hu man corneal endothelial cell cultures with proliferative and senescent morphology, an ex vivo corneal epithelium sample, two primary corneal epithelial cell cultures, two third-passage corneal epithelial cell c ultures, and two stromal fibroblast cultures. The PCR primers used in this study distinguished mRNAs coding for three amino-terminal motifs (alpha, beta, and gamma) of the FGF receptor-1 that are derived by alt ernative splicing from a single genomic sequence. Messenger RNA molecu les coding for FGF receptor-1 amino-terminal motif were detected in co rneal endothelial and epithelial cells. The alpha and beta amino-termi nal motif, but not the gamma amino-terminal motif, mRNAs were detected in stromal fibroblasts. The gamma motif lacks a known signal sequence for membrane translocation and is thought to represent an intracellul ar form of the FGF receptor-1. Identification of mRNA coding for FGF r eceptor-1 along with the previous identification of basic FGF mRNA and protein in corneal endothelial, epithelial, and stromal fibroblast ce lls suggests an autocrine and/or paracrine role for basic FGF in the p hysiology of the cornea.