Figure 1.

VEGF gene structure. The VEGF genomic structure is schematized with 5′UTR containing: P1, TATA less promoter region including hypoxia responsive element (HRE) (13); IP, internal promoter directs the transcription of a truncated mRNA. Three coding exons are alternatively spliced and give rise to several polypeptide, the most abundant are the 121, 165 and 189 amino acids isoforms. The 1038 nucleotides upstream from the AUG contain two IRESes (A and B) and in frame CUGs translation initiation codons that direct the synthesis of L-VEGF, which cleavage generates secreted-VEGF plus the intracellular N-VEGF.