Interaction Between the $oxa1$ and $rmp1$ Genes Modulates Respiratory Complex Assembly and Life Span in $Podospora\ anserina$

Carole H. Sellem (1, 2) , Claire Lemaire (1, 2) , Séverine Lorin (1, 2) , Geneviève Dujardin (1, 2) , Annie Sainsard-Chanet (1, 2)

1 CGM - Centre de génétique moléculaire
2 JOLIOT - Institut des Sciences du Vivant Frédéric JOLIOT

A causal link between deficiency of the cytochrome respiratory pathway and life span was previously shown in the filamentous fungus $Podospora\ anserina$. To gain more insight into the relationship between mitochondrial function and life span, we have constructed a strain carrying a thermosensitive mutation of the gene $oxa1$. OXA1 is a membrane protein conserved from bacteria to human. The mitochondrial OXA1 protein is involved in the assembly/insertion of several respiratory complexes. We show here that $oxa1$ is an essential gene in $P.\ anserina$. The $oxa1$ts mutant exhibits severe defects in the respiratory complexes I and IV, which are correlated with an increased life span, a strong induction of the alternative oxidase, and a reduction in ROS production. However, there is no causal link between alternative oxidase level and life span. We also show that in the $oxa1^{ts}$ mutant, the extent of the defects in complexes I and IV and the life-span increase depends on the essential gene $rmp1$. The RMP1 protein, whose function is still unknown, can be localized in the mitochondria and/or the cytosolic compartment, depending on the developmental stage. We propose that the RMP1 protein could be involved in the process of OXA1- dependent protein insertion

Domains: Life Sciences [q-bio]

Carole H. Sellem, Claire Lemaire, Séverine Lorin, Geneviève Dujardin, Annie Sainsard-Chanet. Interaction Between the $oxa1$ and $rmp1$ Genes Modulates Respiratory Complex Assembly and Life Span in $Podospora\ anserina$. Genetics, 2005, 169 (3), pp.1379-1389. ⟨10.1534/genetics.104.033837⟩. ⟨cea-02470697⟩