Effects of Shmt2 knockout on mitochondrial respiratory chain complexes of livers and brains from E13.5 embryos. (a) Western blot analysis to estimate the quantity of the subunits comprising the mitochondrial respiratory chain complexes for comparison between wild-type and Shmt2-knockout foetal tissues. SHMT2, SHMT2 protein encoded by Shmt2; NDUSF4 and NDUFA9, nuclear DNA-encoded subunits of respiratory chain complex I; MT-CO1, an mtDNA-encoded subunit of respiratory chain complex IV; SDHA, a nuclear DNA-encoded subunit of respiratory chain complex II. Filled blue bars, wild-type foetal livers; filled red bars, Shmt2-knockout foetal livers; open blue bars, wild-type foetal brains; open red bars, Shmt2-knockout foetal brains. Data represent the mean ± S.D. *P < 0.05; **P < 0.01, Student’s t test (wild-type tissues, n = 4; tissues without Shmt2, n = 4). (b) In-gel evaluation of the activity of mitochondrial respiratory chain complex I, and detection of mitochondrial respiratory chain complexes I, III, IV, and V by blue native PAGE. To detect respiratory chain complexes, gels were stained with Coomassie Brilliant Blue R250 (CBBR).