a, A metabolic phenotype plot of oxygen consumption rate (OCR) versus extracellular acidification rate (ECAR). ALKBH7 knockdown decreases mitochondrial activity under both baseline and stress conditions. n = 6 biologically independent samples; data are presented as mean values ± s.d. b, Western blotting showed that ALKBH7 knockdown markedly decreases OXPHOS complex IV assembly by affecting mt-CO1 protein levels (normalized to β-actin). c, Western blotting showed that ALKBH7 depletion leads to a notable decrease in the level of most mt-proteins (normalized to β-tubulin). For b,c, two rounds of immunoblots for biologically independent samples were performed, with similar results obtained. d, A model scheme for the effects of ALKBH7 on mt-RNA processing.