Fig. 7. (A) Evidence for stabilization of HIF1 in Vhlh null primary chondrocytes. Western blot analysis of whole-cell lysate from primary chondrocytes isolated from Vhlh^+f/+f newborn mice and infected with ß-galactosidase (WT) or Cre recombinase (Vhlh null) adenoviral constructs. Levels of Pro564-hydroxylated HIF1 and -tubulin were analyzed. (B) Evidence for increased HIF1 activity in Vhlh null primary chondrocytes. Elisa measurements of soluble VEGF in the supernatant from primary chondrocytes isolated from Vhlh^+f/+f newborn mice and infected with ß-galactosidase (WT) or Cre recombinase (Vhlh null) adenoviral constructs. (C) VEGF, PGK and type II collagen mRNA expression measured by real-time PCR of total RNA isolated from primary chondrocytes isolated from Vhlh^+f/+f newborn mice and infected with ß-galactosidase (WT) or Cre recombinase (Vhlh null) adenoviral constructs.