title: Poly(A)-binding protein-interacting protein 2, a strong regulator of vascular endothelial growth factor mRNA.
abstract: Expression of vascular endothelial growth factor (VEGF) is tightly regulated, particularly at the level of its mRNA stability, which is essentially mediated through the 3'-untranslated region (3'-UTR) of VEGF mRNA. To identify new protein partners regulating VEGF mRNA stability, we screened a cDNA expression library with an RNA probe corresponding to the entire VEGF mRNA 3'-UTR. We identified the "poly(A)-binding protein-interacting protein 2" (PAIP2) as a new VEGF mRNA 3'-UTR interacting protein. By RNA electromobility shift assays, we showed that PAIP2 binds to two distinct regions of a domain encompassing base 1 to 1280 of the VEGF 3'-UTR. Such in vitro interaction was confirmed using cell extracts in which PAIP2 expression is induced by tetracycline (Tet-on cells). Moreover, we demonstrated by RNA affinity purification as well as by ribonucleoprotein complexes immunoprecipitation, that PAIP2 interacts with VEGF mRNA in vivo. Using an in vitro RNA degradation assay, the half-life of VEGF 3'-UTR was found to be increased by overexpressing PAIP2. PAIP2 stabilizes endogenous VEGF mRNA in Tet-on cells, leading to increased VEGF secretion. Moreover, RNAi-mediated knock-down of PAIP2 significantly reduces the steady-state levels of endogenous VEGF mRNA. We also showed, by in vitro protein-protein interactions and co-immunoprecipitation experiments, that PAIP2 interacts with HuR, an already known VEGF mRNA-binding protein, suggesting cooperation of both proteins for VEGF mRNA stabilization. Hence, PAIP2 appears to be a crucial regulator of VEGF mRNA and as a consequence, any variation in its expression could modulate angiogenesis.
authors.affiliation: Institute of Signaling, Developmental Biology and Cancer Research, CNRS-UMR 6543, Centre Antoine Lacassagne, 33 avenue de Valombrose, 06189 Nice cedex 2, France.
authors.forename: Cercina
authors.initials: C
authors.lastname: Onesto
authors.forename: Edurne
authors.initials: E
authors.lastname: Berra
authors.forename: Renaud
authors.initials: R
authors.lastname: Grépin
authors.forename: Gilles
authors.initials: G
authors.lastname: Pagès
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001667:Binding, Competitive; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D000860:Hypoxia; D051379:Mice; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013752:Tetracycline / Q000494:pharmacology; D013997:Time Factors; D014018:Tissue Distribution; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; D002352:Carrier Proteins; D018076:DNA, Complementary; C488448:PAIP2 protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D042461:Vascular Endothelial Growth Factor A; D012313:RNA; D005982:Glutathione Transferase; D013752:Tetracycline