Cloning and characterization of a novel form of mouse fibroblast growth factor-1 (FGF-1) mRNA, FGF-1.G: differential expression of FGF-1 and FGF-1.G mRNAs during embryonic development and in postnatal tissues.
The fibroblast growth factor-1 (FGF-1) gene is characterized by the presence of different untranslated exons in its 5' end that direct the expression of alternatively spliced mRNA variants (1.A, 1.B and 1.C) that encode for FGF-1. We have previously isolated a new mouse FGF-1 upstream untranslated exon, which we termed -1G. Here we report on the cloning and characterization of the FGF-1 mRNA isoform arising from -1G. This newly identified FGF-1 mRNA species (FGF-1.G), whose transcription start site maps 295 bp upstream from the splice donor site, is predominantly expressed in young liver and kidney, where it comprises 40.2% and 30.7%, respectively, of the total FGF-1 mRNA. While the FGF-1 mRNA comprising all of the FGF-1 transcripts was present in distinct tissues at embryonic days E12.5 and E15.5, the FGF-1.G mRNA was not detected during murine embryogenesis; therefore the role of FGF-1 in embryonic development must be attributed to FGF-1 mRNAs arising from upstream untranslated exons other than -1G. On the other hand, the parallel decrease of both FGF-1 and FGF-1.G mRNA levels we observed in the aging mouse kidney and liver suggests a role of FGF-1.G in normal cellular maintenance and survival.
Zhang
Y
Y
Department of Internal Medicine, Ohio State University, William H. Davis Medical Research Center, Columbus 43210, USA.
Madiai
F
F
Hackshaw
K V
KV
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis; D004622:Embryo, Mammalian; D005091:Exons; D016220:Fibroblast Growth Factor 1 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007668:Kidney / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D008099:Liver / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics; D015347:RNA Probes; D012333:RNA, Messenger / Q000096:biosynthesis*
D018076:DNA, Complementary; D020033:Protein Isoforms; D015347:RNA Probes; D012333:RNA, Messenger; D016220:Fibroblast Growth Factor 1