A) Schematic of promoter organization of the human GlcAT-I gene showing location of major transcription factor binding sites. The transcription start site is marked as +1. HRE is shown as triangle, TonE as flattened circle, Sp1 are indicted as ovals while the NFAT binding motifs are shown as rectangles. B) Stretches of DNA sequence of the GlcAT-I promoter containing HRE (GCGTG/CACGC) motifs that are marked in bold and underlined. C) Cartoon showing map of successive PCR generated 5′ deletion constructs of the human GlcAT-I promoter. D) Basal activities of GlcAT-I promoter constructs in normoxia and hypoxia relative to full length construct GD in NP cells. E) Hypoxic regulation of GlcAT-I promoter constructs in NP cells. Constructs GD and GM show increase in activity in hypoxia, whereas activity of construct GP is unaffected. F) Relative activities of promoter constructs in N1511 chondrocytes. G) Chondrocytes show hypoxic induction in activity of construct GD, activity of shorter constructs GM and GP is unaffected. Values shown are mean ± SE, of 3 independent experiments; *p<0.05.