FIG 3.

Identification of CTSB as an HIF-2 target. (A) Primary human macrophages were transfected with siRNA (50 nM) against HIF-1α (si1), HIF-2α (si2), or a scrambled control (scr). Cells were incubated for 0 and 48 h under hypoxia. (B) mRNA was isolated from wild-type (wt), scrambled (scr), HIF-1α (si1), and HIF-2α (si2) knockdown macrophages to analyze CTSB mRNA expression by qPCR. Data are normalized to TBP expression, and the wt control was set to 1. (C) Results of ChIP-Seq data visualizing HIF-1α and -2α binding to the CTSB enhancer region using the UCSC Genome Browser. (D) HIF binding to the CTSB enhancer was analyzed after 4 h of hypoxia by ChIP, using HIF-1α- or HIF-2α-specific antibodies. Enrichment is shown as the percentage of input. Data are expressed as means ± SEM (n ≥ 3 experiments). *, P < 0.05.