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A homologue of the yeast SHE4 gene is essential for the transition between the syncytial and cellular stages during sexual reproduction of the fungus Podospora anserina
Author(s) -
BerteauxLecellier Véronique,
Zickler Denise,
Debuchy Robert,
PanvierAdoutte Arlette,
ThompsonCoffe Catherine,
Picard Marguerite
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.5.1248
Subject(s) - podospora anserina , biology , sexual reproduction , gene , genetics , yeast , fungus , mutation , reproduction , fungal protein , saccharomyces cerevisiae , evolutionary biology , microbiology and biotechnology , botany , mutant
The Podospora anserina cro1 gene was identified as a gene required for sexual sporulation. Crosses homozygous for the cro1‐1 mutation yield fruiting bodies which produce few asci due to the formation of giant plurinucleate cells instead of dikaryotic cells after fertilization. This defect does not impair karyogamy, but meioses of the resultant polyploid nuclei are most often abortive. Cytological studies suggest that the primary defect of the mutant is its inability to form septa between the daughter nuclei after each mitosis, a step specific for normal dikaryotic cell divisions. The cro1‐1 mutant would thus be unable to leave the syncytial vegetative state while abiding by the meiotic programme. cro1‐1 also shows defects in ascospore germination and growth rate. GFP‐tagging of the CRO1 protein reveals that it is a cytosolic protein mainly expressed at the beginning of the dikaryotic stage and at the time of ascospore maturation. The CRO1 protein exhibits significant similarity to the SHE4 protein, which is required for asymmetric mating‐type switching in budding yeast cells. Thus, a gene involved in asymmetric cell divisions in a unicellular organism plays a key role at the transition between the syncytial (vegetative) state and the cellular (sexual) state in a filamentous fungus.