The structure and expression of the FGF receptor-1 mRNA isoforms in rat tissues.
In this paper, we describe the structure of rat FGF receptor-1 mRNA isoforms and their expression in a variety of rat tissues. The rat FGFR-1 has the characteristics of FGFR-1 as well as mouse, human and chicken homologs. FGFR-1 mRNA was detectable in all the tissues examined by Northern analysis or polymerase chain reaction, indicating that FGFR-1 mRNA is widely expressed in rat tissues. The rat FGFR-1 mRNA has isoforms in both the extracellular and intracellular regions. The extracellular isoforms which have two or three immunoglobulin-like domains, are expressed almost equally in the tissues except for brain. However, the large form is a major form in the brain. Furthermore, in the brain, half of FGFR-1 mRNAs have the six nucleotides, which encode a potential serine-threonine kinase phosphorylation site in the intracellular juxta-membrane region, deleted. In contrast to the brain, the deletion isoform is a minor form in the other tissues. The tissue-specific expression of the isoforms indicates that they have different physiological functions. Although other isoforms of FGFR-1 mRNA in tumor cell lines have been reported, the isoforms were undetectable in all rat tissues examined, indicating the isoforms are products of abnormal alternative splicing in tumor cell lines.
Yazaki
N
N
Department of Biological Chemistry, Kyoto University, Faculty of Pharmaceutical Sciences, Japan.
Fujita
H
H
Ohta
M
M
Kawasaki
T
T
Itoh
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000502:physiology*; D002645:Chickens; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005346:Fibroblast Growth Factors / Q000378:metabolism; D014644:Genetic Variation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016133:Polymerase Chain Reaction / Q000379:methods; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D011956:Receptors, Cell Surface / Q000235:genetics*; D017468:Receptors, Fibroblast Growth Factor
D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017468:Receptors, Fibroblast Growth Factor; D005346:Fibroblast Growth Factors; D004247:DNA; C496348:FGFR1 protein, human; C496349:Fgfr1 protein, mouse; C496350:Fgfr1 protein, rat; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1