Non-mendelian inheritance of the HET-s prion or HET-s prion domains determines the het-S spore killing system in Podospora anserina

Fungal Genet Biol. 2005 Oct;42(10):836-47. doi: 10.1016/j.fgb.2005.05.004.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics*
  • Fungal Proteins / physiology*
  • Microscopy, Fluorescence
  • Podospora / cytology
  • Podospora / genetics*
  • Podospora / physiology*
  • Prions / genetics
  • Protein Interaction Mapping
  • Protein Structure, Tertiary*
  • Spores, Fungal / cytology
  • Spores, Fungal / genetics
  • Spores, Fungal / physiology

Substances

  • Fungal Proteins
  • HET-S protein, Podospora anserina
  • Prions