Non-mendelian inheritance of the HET-s prion or HET-s prion domains determines the het-S spore killing system in Podospora anserina.
Two alleles of the het-s/S locus occur naturally in the filamentous fungus Podospora anserina, het-s and het-S. The het-s encoded protein can form a prion that propagates a self-perpetuating amyloid aggregate, resulting in two phenotypes for the het-s strains. The prion-infected [Het-s] shows an antagonistic interaction to het-S whereas the prion-free [Het-s*] is neutral in interaction to het-S. The antagonism between [Het-s] and het-S is seen as heterokaryon incompatibility at the somatic level and as het-S spore killing in the sexual cycle. Two different domains of the HET-s and HET-S proteins have been identified, and a structure-function relationship has been established for interactions at the somatic level. In this study, we correlate accumulation of the HET-s and HET-S proteins (visualized using GFP) during the sexual cycle with timing of het-S spore abortion. Also, we present the structure-function relationship of the HET-s domains for interactions in the sexual cycle. We show that the constructs that ensure het-s incompatibility function in somatic mycelium are also active in het-S spore killing in the sexual cycle. In addition, paternal prion transmission and het-S spore killing has been found with the HET-s(157-289) truncated protein. The consequences of the unique transition from a coenocytic to a cellular state in the sexual phase and the timing, and localization of paternal and maternal HET-s and HET-S expression that are pertinent to prion transmission, and het-S spore killing are elaborated. These data further support our previously proposed model for het-S spore killing.
Dalstra
Henk J P
HJ
Laboratory of Genetics, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands.
van der Zee
Remko
R
Swart
Klaas
K
Hoekstra
Rolf F
RF
Saupe
Sven J
SJ
Debets
Alfons J M
AJ
D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D008856:Microscopy, Fluorescence; D048468:Podospora / Q000166:cytology / Q000235:genetics* / Q000502:physiology*; D011328:Prions / Q000235:genetics; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D013172:Spores, Fungal / Q000166:cytology / Q000235:genetics / Q000502:physiology
D005656:Fungal Proteins; C083891:HET-S protein, Podospora anserina; D011328:Prions