title: HET-E and HET-D belong to a new subfamily of WD40 proteins involved in vegetative incompatibility specificity in the fungus Podospora anserina.
abstract: Vegetative incompatibility, which is very common in filamentous fungi, prevents a viable heterokaryotic cell from being formed by the fusion of filaments from two different wild-type strains. Such incompatibility is always the consequence of at least one genetic difference in specific genes (het genes). In Podospora anserina, alleles of the het-e and het-d loci control heterokaryon viability through genetic interactions with alleles of the unlinked het-c locus. The het-d2(Y) gene was isolated and shown to have strong similarity with the previously described het-e1(A) gene. Like the HET-E protein, the HET-D putative protein displayed a GTP-binding domain and seemed to require a minimal number of 11 WD40 repeats to be active in incompatibility. Apart from incompatibility specificity, no other function could be identified by disrupting the het-d gene. Sequence comparison of different het-e alleles suggested that het-e specificity is determined by the sequence of the WD40 repeat domain. In particular, the amino acids present on the upper face of the predicted beta-propeller structure defined by this domain may confer the incompatible interaction specificity.
authors.affiliation: Institut de Biochimie et de Génétique Cellulaires, CNRS UMR 5095, 33077 Bordeaux, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Espagne
authors.forename: Pascale
authors.initials: P
authors.lastname: Balhadère
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Penin
authors.forename: Christian
authors.initials: C
authors.lastname: Barreau
authors.forename: Béatrice
authors.initials: B
authors.lastname: Turcq
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins; D019204:GTP-Binding Proteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D020449:Repetitive Sequences, Amino Acid; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D020037:Sordariales / Q000235:genetics / Q000502:physiology*
chemical_list: D005656:Fungal Proteins; C095738:HET-E1 protein, Podospora anserina; D019204:GTP-Binding Proteins