Molecular and biochemical analysis of Saccharomyces cerevisiae $cox1$ mutants

C. Lemaire (1, 2) , S. Robineau (1, 2) , P. Netter (1, 2)

1 CGM - Centre de génétique moléculaire
2 CEA - Commissariat à l'énergie atomique et aux énergies alternatives

We report on the molecular and biochemical analysis of a set of 13 respiratory deficient mutants of $Saccharomyces\ cerevisiae$ which are specifically altered in $COX1$, the gene encoding the subunit Cox1p of cytochrome c oxidase. DNA sequence analysis shows that three are due to frameshift mutations, two to nonsense mutations, and eight to missense mutations. All, except the missense mutant S157L, have impaired electron transfer and respiratory activity. Analysis of the mitochondrial translation products shows that when Cox1p is absent, Cox2p and Cox3p are still synthesized. In the missense mutants, the steady state levels in the mitochondrial membranes of the three mitochondrially encoded subunits Cox1p, Cox2p and Cox3p and the nuclear-encoded subunit Cox4p are reduced. In the frameshift and nonsense mutants, Cox1p is absent and Cox2p, Cox3p and Cox4p are considerably decreased or undetectable. A comparison of the steady state levels of Cox1p through Cox4p in the $COX1$, $COX2$, $COX3$ and $COX4$ mutants shows the interdependance of the accumulation of these four subunits in the mitochondrial membranes.

Mots clés: Cytochrome c oxidase; $Saccharomyces\ cerevisiae$; Complex assembly

Domaines: Sciences du Vivant [q-bio]

C. Lemaire, S. Robineau, P. Netter. Molecular and biochemical analysis of Saccharomyces cerevisiae $cox1$ mutants. Current Genetics, 1998, 34, pp.138-145. ⟨10.1007/s002940050378⟩. ⟨cea-02474767⟩