Fibroblast growth factor-1 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 messenger ribonucleic acid (mRNA) sequences in cDNA samples prepared from human 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 cultures, and two stromal fibroblast cultures. The PCR primers used in this study distinguished mRNAs coding for three aminoterminal motifs (alpha, beta, and gamma) of the FGF receptor-1 that are derived by alternative splicing from a single genomic sequence. Messenger RNA molecules coding for FGF receptor-1 amino-terminal motif were detected in corneal endothelial and epithelial cells. The alpha and beta amino-terminal 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 intracellular form of the FGF receptor-1. Identification of mRNA coding for FGF receptor-1 along with the previous identification of basic FGF mRNA and protein in corneal endothelial, epithelial, and stromal fibroblast cells suggests an autocrine and/or paracrine role for basic FGF in the physiology of the cornea.