X-Message-Number: 26309
Date: Thu, 9 Jun 2005 21:51:02 -0700 (PDT)
From: Doug Skrecky <>
Subject: more on mitochondria & podospora anserina

Genetics. 2005 Mar;169(3):1379-89. Epub 2004 Nov 15.
Interaction between the oxa1 and rmp1 genes modulates respiratory
complex assembly and life span in Podospora anserina.
    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.

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