Heterogeneity of 3'untranslated region of bovine acidic FGF transcripts

A bovine aFGF genomic clone (14.2 Kb) has been isolated and characterized. This clone contains exons 2 and 3 interrupted by 6.7 Kb long intron. Exon 3 contains part of the coding region and the 3' untranslated region (3'UTR). Two overlapping cDNA clones specific for this 3'UTR have been isolated from bovine retina cDNA libraries or after amplification of RNA by the RACE technique. Analysis of these clones and RNAse protection assay demonstrate alternative termination of aFGF transcripts giving rise to differently sized 3'UTR of 2.5 Kb and at least 3.9 Kb. The sequence of these long 3'UTR is highly conserved among species (70% identity between human and rat) which suggests an important role for aFGF expression.