ABC1, a novel yeast nuclear gene has a dual function in mitochondria: it suppresses a cytochrome b mRNA translation defect and is essential for the electron transfer in the bc 1 complex

EMBO J. 1991 Aug;10(8):2023-31.


We have cloned and sequenced a novel yeast nuclear gene ABC1 which suppresses, in multicopy, the cytochrome b mRNA translation defect due to the nuclear mutation cbs2-223. Analysis of the ABC1 gene shows that it is weakly expressed, it could code for a protein of 501 amino acids which has a typical presequence of a protein imported into mitochondria and which does not display a strong similarity to any known protein. Inactivation of the ABC1 gene is not lethal to the cell but leads to a respiratory defect: no oxygen uptake and no growth on non-fermentable media. A total absence of NADH-cytochrome c oxidoreductase and succinate-cytochrome c oxidoreductase activities concomitant with the presence of specific dehydrogenases, suggests a block in the bc 1 segment of the respiratory chain. However, all the cytochromes are spectrally detectable. Cytochrome b is quite efficiently reduced while cytochromes c1 and c are not. The function of ABC1 in the suppression of a defect in apocytochrome b mRNA translation and in the activity of the bc1 complex suggests that the ABC1 protein would be a novel chaperonin involved both in biogenesis and bioenergetics of mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Nucleus / metabolism
  • Chromosomes, Fungal
  • Cytochrome b Group / genetics*
  • Electron Transport
  • Electron Transport Complex III / metabolism
  • Genes, Fungal*
  • Mitochondria / enzymology
  • Mitochondria / metabolism*
  • Molecular Sequence Data
  • Mutation
  • Nucleic Acid Hybridization
  • Protein Biosynthesis*
  • RNA, Messenger / genetics*
  • Restriction Mapping
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism


  • Cytochrome b Group
  • RNA, Messenger
  • Electron Transport Complex III

Associated data

  • GENBANK/M55400
  • GENBANK/M55401
  • GENBANK/M55402
  • GENBANK/M65224
  • GENBANK/S40855
  • GENBANK/S60919
  • GENBANK/S60920
  • GENBANK/X57550
  • GENBANK/X58577
  • GENBANK/X59027
  • GENBANK/X59082