Altered form of subunit 6 of mitochondrial ATP synthase complex in oligomycin-resistant mutants of Chinese hamster ovary cells

Abstract

Using an antiserum generated against a synthetic peptide predicted from the DNA sequence of the ATPase 6 gene of the mitochondrial DNA, we demonstrate that mitochondria from two oligomycin-resistant Chinese hamster ovary cell lines with a defined mutation in the ATPase 6 gene synthesize an altered ATPase 6 gene product. This altered gene product migrates in sodium dodecyl sulfate-polyacrylamide gels as if it has a molecular mass that is larger by 1000 daltons than the wild-type ATPase 6 gene product. We also demonstrate that mitochondria from four other independently isolated oligomycin-resistant Chinese hamster ovary mutant cell lines contain a similar altered ATPase 6 gene product. These results suggest that all six oligomycin-resistant cell lines have a similar mutation in the ATPase 6 gene of the mitochondrial DNA that encodes subunit 6 of the ATP synthase complex.