Fig. 5. mitoERβ activates the transcription of mitochondrial genes in TNBC MDA-MB-231 and -436 cells. Quantitative RT-PCR analysis of mitochondrial gene mRNA levels in Mock-, pHA-ERβ-, pHA-ERβ△N-, and pHA-ERβ△C-transfected MDA-MB-231 (A) and MDA-MB-436 (B) TNBC cell lines. ERβ and ERβ△N expression was confirmed by immunoblotting after subcellular fractionation. C. MCF7 cells were harvested for chromatin immunoprecipitation analysis using anti-ERβ antibody or normal IgG. The association of ERβ with the mitochondrial D-loop region was determined by qPCR. Right panel, Schematic view of the ERβ-binding sites in the mitochondrial D-loop region. D. MDA-MB-231 cells were transfected with pHA-mito-ERβ or Mock plasmid, and the cells were harvested for chromatin immunoprecipitation analysis using an anti-HA antibody.