IDC1, a pezizomycotina-specific gene that belongs to the PaMpk1 MAP kinase transduction cascade of the filamentous fungus Podospora anserina.

Components involved in the activation of the MAPK cascades in filamentous fungi are not well known. Here, we provide evidence that IDC1, a pezizomycotina-specific gene is involved along with the PaNox1 NADPH oxidase in the nuclear localization of the PaMpk1 MAP kinase, a prerequisite for MAPK activity. Mutants of IDC1 display the same phenotypes as mutants in PaNox1 and PaMpk1, i.

What triggers senescence in Podospora anserina?

Senescence of Podospora anserina is triggered by a cytoplasmic and infectious factor (the determinant of senescence) and is always correlated with mitochondrial DNA modifications, especially with the accumulation of small circular subgenomic DNA molecules, the senDNAs. Several observations have suggested that the senDNAs could be the cytoplasmic and infectious determinant. However, we show here (1) that senDNA molecules can be transferred to a young culture without the cotransmission of the determinant of senescence and (2) that the determinant of senescence does not segregate as a mitochondrial DNA mutation.

Mutations in genes encoding the mitochondrial outer membrane proteins Tom70 and Mdm10 of Podospora anserina modify the spectrum of mitochondrial DNA rearrangements associated with cellular death.

Tom70 and Mdm10 are mitochondrial outer membrane proteins. Tom70 is implicated in the import of proteins from the cytosol into the mitochondria in Saccharomyces cerevisiae and Neurospora crassa. Mdm10 is involved in the morphology and distribution of mitochondria in S.

Contribution of various classes of defective mitochondrial DNA molecules to senescence in Podospora anserina.

The unavoidable arrest of vegetative growth in Podospora anserina (senescence process) is always correlated with rearrangements of the mitochondrial chromosome, mainly consisting in the amplification of particular regions as tandemly repeated circular molecules (senDNAs). One sequence systematically amplified in senescent cultures corresponds precisely to the first intron (intron alpha) of the cox1 gene; nevertheless, other regions (called beta and gamma) are also frequently amplified. The experiments presented in this paper show that cellular death is in some cases associated with the sole presence of large amounts of senDNA beta.

Intramolecular cross-overs generate deleted mitochondrial DNA molecules in Podospora anserina.

The unavoidable senescence process that limits the vegetative growth of Podospora anserina is always associated with an accumulation of various classes of circular, tandemly arranged, defective mitochondrial DNA molecules (senDNAs). The monomers of the senDNAs belonging to the so-called beta class share a common core, but differ in both their length and termini. To understand the mechanism leading to their formation, we have determined the junction sequence of 36 senDNA beta monomers present in various senescent cultures.