THE VASCULAR ENDOTHELIAL GROWTH-FACTOR MESSENGER-RNA CONTAINS AN INTERNAL RIBOSOME ENTRY SITE

Vascular endothelial growth factor (VEGF), an essential regulator of a ngiogenesis during early development as well as during the growth of s olid tumours, bears an unusually large 5' untranslated region (5'-UTR) in the mRNA of over 1000 nucleotides, We found that the VEGF 5'-UTR, despite being GC-rich and containing an upstream short open reading fr ame, promotes efficient translation of a luciferase reporter. The VEGF 5'-UTR also allowed translation of luciferase from a dicistronic mRNA when placed between the two cistrons, demonstrating that it contains an internal ribosome entry site. Deletion analysis indicated that the IRES resides towards the 3' end of the 5'-UTR, (C) 1998 Federation of European Biochemical Societies.