Identification of a Novel Alternative Splicing of Human FGF Receptor 4: Soluble-Form Splice Variant Expressed in Human Gastrointestinal Epithelial Cells

摘要: Among four closely related members of the FGF receptor family, FGFR 1, 2, and 3 have alternative splicing forms encoded by different exons for C-terminal half third Ig-like domain, but 4 has no such exon. Furthermore, another splice variant nontransmembrane type; however, a not been reported 4. While searching novel receptor-type tyrosine kinase RT-PCR, we identified non-transmembrane-type in human intestinal epithelial cell lines (Intestine 407 Caco-2). Sequence analysis this revealed that exon 9 coding single transmembrane domain was displaced intron 9. Consequently, form 120 bp shorter than normal had portion. Moreover, signal sequence 2 maintained, suggesting is soluble receptor. This detected gastrointestinal cells pancreas, also gastric, colon, pancreatic cancer lines. Single RT-PCR showed expressed simultaneously with transmembrane-type same cell. Western blot secreted from transfected COS7 cells. Thus, soluble-form first report