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Splice factor regulation of alternative splicing of VEGF isoform families
Author(s) -
Woolard J,
Nowak D,
Ladomery M,
Harper S J,
Bates D O
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a539
Subject(s) - alternative splicing , rna splicing , gene isoform , exon , splice , splicing factor , transfection , blot , biology , microbiology and biotechnology , vascular endothelial growth factor , sr protein , chemistry , gene , vegf receptors , cancer research , genetics , rna
VEGF, a potent angiogenic factor, exists as two families of isoforms formed by differential distal splice acceptor site selection in the terminal exon. The VEGF xxx b family contains an alternate C terminus resulting in endogenous anti‐angiogenic activity. The mechanisms by which alternative splicing of VEGF is regulated are unclear, so the present study aimed to investigate splicing factors involved in the switch from the anti‐to pro‐angiogenic state. Retinal Pigmented Epithelial (RPE) cells, known to express both VEGF xxx and VEGF xxx b, were transfected with plasmids expressing specific splicing factors ASF/SF2, 9G8, SRp55, or SRp40 under control of a CMV promoter, and total protein and conditioned medium collected and analysed by Western Blotting and ELISA. ASF/SF2 did not significantly increase the amount of VEGF xxx b, but increased the amount of VEGF total (mean±SEM, n=3 41.4%±6.9%, p<0.05). 9G8 significantly increased both VEGF xxx b (78.6%±4.7%, p<0.01) and VEGF total (13.7%±2.9%, p<0.05) levels. SRp55 increased the amount of VEGF xxx b (104.5%±18.0%, p<0.01) but did not increase VEGF total . SRp40 did not alter the amount of VEGF total or VEGF xxx b protein. Compared with untreated RPE cells ASF/SF2, SRp55 and SRp40 appeared to decrease the amount of VEGF total protein detected in the medium by 12.8%± 4.8%, 70.9%±3.6%, and 34.1%±4.6%, respectively. 9G8 did not affect the level of VEGF total . These results indicate that that splicing factors such as ASF/SF2, 9G8, and in particular SRp55, regulate alternative splicing of the VEGF gene. SOURCE OF RESEARCH SUPPORT: AICR