A multi-protein complex containing cold shock domain (Y-box) and polypyrimidine tract binding proteins forms on the vascular endothelial growth factor mRNA. Potential role in mRNA stabilization.
Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and post-transcriptional regulation plays a major role in VEGF expression. Both the 5'- and 3'-UTR are required for VEGF post-transcriptional regulation but factors binding to functional sequences within the 5'-UTR have not been fully characterized. We report here the identification of complexes, binding to the VEGFmRNA 5'- and 3'-UTR, that contain cold shock domain (CSD) and polypyrimidine tract binding (PTB) RNA binding proteins. Analysis of the CSD/PTB binding sites revealed a potential role in VEGF mRNA stability, in both noninduced and induced conditions, demonstrating a general stabilizing function. Such a stabilizing mechanism had not been reported previously for the VEGF gene. We further found that the CSD/PTB-containing complexes are large multiprotein complexes that are most likely preformed in solution and we demonstrate that PTB is associated with the VEGF mRNA in vivo. Complex formation between CSD proteins and PTB has not been reported previously. Analysis of the CSD/PTB RNA binding sites revealed a novel CSD protein RNA recognition site and also demonstrated that CSD proteins may direct the binding of CSD/PTB complexes. We found the same complexes binding to an RNA-stabilizing element of another growth factor gene, suggesting a broader functional role for the CSD/PTB complexes. Finally, as the VEGF gene is also regulated at the transcriptional level by CSD proteins, we propose a combined transcriptional/post-transcriptional role for these proteins in VEGF and other growth factor gene regulation.
Coles
Leeanne S
LS
Division of Human Immunology, The Hanson Institute, Institute of Medical and Veterinary Science, Adelaide, South Australia, Australia. leeanne.coles@imvs.sa.gov.au
Bartley
M Antonetta
MA
Bert
Andrew
A
Hunter
Julie
J
Polyak
Steven
S
Diamond
Peter
P
Vadas
Mathew A
MA
Goodall
Gregory J
GJ
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002850:Chromatography, Gel; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics; D019169:Jurkat Cells; D010957:Plasmids; D038941:Polypyrimidine Tract-Binding Protein / Q000235:genetics / Q000378:metabolism*; D015347:RNA Probes; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D007376:Interleukin-2; D015347:RNA Probes; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C094867:YBX3 protein, human; D038941:Polypyrimidine Tract-Binding Protein