Mitochondrial ER-beta binding sites. (A) Genome Browser view of the ERβ binding site identified in mitochondrial genome. (B) Validation of ERβ binding to mitochondrial DNA by ChIP. Results shown are representative of duplicate analyses. E2: 10-8M 17β-estradiol; PPT: 10-8M 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole (selective ERα agonist); DPN: 10-8M 2,3-bis(4-hydroxyphenyl) propionitrile (ERβ agonist). (C) Western blot analysis of ERβ and/or ERα in purified mitochondria from Ct-ERβ and Ct-ERα  cells. Cyt: cytosol depleted of mitochondria, H: whole cell homogenate; Mito: purified mitochondrial fraction. ATPase is a mitochondrial marker and α-tubulin was included to determine the level cytosolic contaminants in 'Mito' samples.