Biochemical, cellular and molecular identification of DNA polymerase α in yeast mitochondria

► Yeast mitochondria contain a second DNA polymerase activity not encoded by the MIP1 gene. ► Use of DNA synthesis inhibitors confirm the presence of DNA pol α in highly purified yeast mitochondria. ► Proteinase K and digitonine-treated yeast mitochondria contains DNA pol α. ► Mass spectrometry and peptide sequencing identifies pol α in yeast mitochondria. ► Confocal microscopy demonstrated that DNA polymerase alpha is dually localized in nuclei and mitochondria in yeast.