eEF1A controls ascospore differentiation through elevated accuracy, but controls longevity and fruiting body formation through another mechanism in Podospora anserina

Antisuppressor mutations in the cEFIA gene of Podospora. anserina were prev iously shown to impair ascospore formation, to drastically increase life sp an, and to pen-nit the development of the Crippled Growth degenerative proc ess. Here, we show that eEF1A controls ascospore formation through accuracy level maintenance. Examination of antisuppressor mutant perithecia reveals two main cytological defects, mislocalization of spindle and nuclei and nu clear death. Antisuppression levels are shown to be highly dependent upon b oth the mutation site and the suppressor used, precluding any correlation b etween severity of ascospore antisuppression efficiency and severity of the sporulation impairment. Nevertheless differentiation defect is correlated with resistance to paromomycin. We also that eEF1A controls fruiting body f ormation and longevity through a mechanism(s) different from accuracy contr ol. In vivo, GFP tagging of the protein in a way that partly retains its fu nction confirmed earlier cytological observation; i.e., this factor is main ly diffuse within the cytosol, but May transiently accumulate within nuclei or in defined regions of the cytoplasm. These data emphasize the fact that the translation apparatus exerts a global regulatory control over cell phy siology and that eEF1A is one of the key factors involved in this monitorin g.