Formate production in mitochondria isolated from wildtype or Mthfd1l−/− embryos.
A, [14C]formate produced from l-[3-14C]serine in mitochondria isolated from pooled E14.5 to E16.5 embryos. Due to limited amounts of mitochondria available from the pooled embryos of each genotype, each data point represents a single reaction. B, representative immunoblot of MTHFD1L and ALDH1L2 expression in mitochondria isolated from E16.5 embryos. Each lane was loaded with 20 μg of protein. Immunoblots were probed with antibodies against MTHFD1L (100 kDa), ALDH1L2 (100 kDa), or the mitochondrial matrix protein Hsp60 (60 KDa) as a loading control. Migration and size (kDa) of molecular mass markers are shown on the right of the blots.