Murine Fibroblast Growth Factor Receptor 1 Gene Generates Multiple Messenger RNAs Containing Two Open Reading Frames via Alternative Splicing

Abstract

The arrangement of exons and introns encoding 5′-side of murine fibroblast growth factor (FGF) receptor 1 (FGFR-1) gene was mapped. A large intron with a site of 14 kb was identified between exon 1 and exon 2. In addition, all FGFR-1 subtypes including a unique variant form with 12 amino acids insertion and two amino acids deletion were observed to be able to be generated through alternative splicing. Furthermore, complete sequencing of the 5′-region of FGFR-1 mRNA revealed that a relatively large open reading frame precedes the major open reading frame encoding FGFR-1. These results indicate that FGFR-1 mRNAs are uniquely translated from an internal translation start site.