Binding of Carbonic Anhydrase IX to 45S rDNA Genes Is Prevented by Exportin-1 in Hypoxic Cells

Figure 2

Chromatin immunoprecipitation analysis of CA IX and UBF1 binding to 45S rDNA precursor gene clusters. Normoxic or hypoxic HEK293 (a) and SHSY-5Y (b) cells were subjected to ChIP analysis with UBF1 or CA IX monoclonal antibodies, as indicated (upper charts). Binding of the proteins to 45S rDNA genes was evaluated via quantitative PCR analysis from triplicate samples. Calculated values for pairwise comparisons of ChIP data were in the 0.0038 to 0.03 range (Student’s -test). The middle panels show the results of qRT-PCR analysis of CA IX or 45S rRNA transcripts from normoxic or hypoxic HEK293 (a) and SHSY-5Y (b) cells. Calculated values for pairwise comparisons of qRT-PCR data were in the 0.0027 to 0.04 range. Lower panels show the hypoxia-induced increases in HIF1α and CA IX protein levels in normoxic (N) or hypoxic (H) HEK293 (a) and SHSY-5Y (b) cells. Filters were reprobed to β-actin, which was used as a loading control.

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