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. 2002 May 14;99(10):7021–7026. doi: 10.1073/pnas.102660199

Figure 2.

Figure 2

Hypoxia-induced gene expression in oxygen-deprived NB cells. (A) Accumulation of HIF-1α and HIF-2α in NB cells in response to oxygen deprivation. Human NB cells were exposed to the indicated oxygen levels for 4 h and subjected to Western blot analysis. Membranes containing identical protein lysates were analyzed with anti-HIF-1α or anti-HIF-2α Abs, which revealed accumulation of proteins of about 120 kDa, in cells grown at 0% or 1% oxygen. A protein unknown to us (indicated by *) appeared in the HIF-2α blots in all experiments. Hypoxia-exposed HeLa cells were used as positive controls for HIF-1α and HIF-2α protein accumulation, also verified with in vitro-translated (i v t) human HIF-1α and mouse HIF-2α, respectively. (B) Western blot analysis showing increased TH levels in NB cells after a 72-h exposure to hypoxia. The non-NB cell lines, HeLa and SK-N-MC, did not express TH. TH expression was detected in SH-SY5Y cells when the film was exposed for a longer time (Right). (C) Northern blot analysis of total RNA from NB cell lines, showing hypoxia-induced expression of VEGF, GAPDH, and IGF-2. The 28S-RNA level was used as a loading control. Representative data of more than two experiments are shown.