Expression and splicing of FGF receptor mRNAs during APRE-19 cell differentiation in vitro.
OBJECTIVE
The expression and alternative splicing of the four FGF receptor (FGFR) mRNAs are regulated in a developmental- and tissue-specific fashion. Capability of differentiation in vitro of the retinal pigment epithelial cell line ARPE-19 has been previously demonstrated. In this study, the hypothesis that FGF receptor gene expression and the alternative splicing of the FGFR1 mRNA is regulated as a function of ARPE-19 differentiation in vitro was tested.


METHODS
ARPE-19 cells were plated at sparse or confluent densities and maintained in culture up to 14 months. The expression of FGF receptors and the ratio of the FGFR1beta to FGFR1alpha splice variants of the FGFR1 transcript were quantified by a published PCR technique. Two in vivo samples of human RPE served as controls.


RESULTS
Sparse cultures of ARPE-19 cells predominantly express FGFR1. When these cultures are allowed to differentiate, FGFR2 is also expressed. Samples of mRNA from RPE cells in vivo exhibit FGFR1 and FGFR2 expression as well as FGFR3 expression, a form that is minimally apparent in vitro. The ratio of the FGFR1beta to FGFR1alpha splice variant decreases as a function of cell differentiation in vitro and approaches the ratio observed in human RPE cells in vivo. Stimulation of cultures in vitro with FGF2 as a prototypical differentiation agent does not regulate the ratio of the FGFR1beta to FGFR1alpha splice variant.


CONCLUSIONS
Differentiation of the ARPE-19 cell line in vitro recapitulates many but not all the in vivo patterns of FGFR expression and splicing. This in vitro system may be useful for selected studies on how cellular differentiation regulates FGF receptor gene expression and splicing.
Alizadeh
M
M
Section of Molecular and Cellular Biology, University of California, Davis 95616-8794, USA.
Gelfman
C M
CM
Bench
S R
SR
Hjelmeland
L M
LM
D017398:Alternative Splicing / Q000235:genetics*; D015152:Blotting, Northern; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D015870:Gene Expression; D006133:Growth Substances / Q000494:pharmacology; D006207:Half-Life; D006801:Humans; D010857:Pigment Epithelium of Eye / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D017468:Receptors, Fibroblast Growth Factor / Q000096:biosynthesis / Q000235:genetics*; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D006133:Growth Substances; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D011994:Recombinant Proteins