Rab-GDI Complex Dissociation Factor Expressed through Translational Frameshifting in Filamentous Ascomycetes

In the model fungus Podospora anserina, the PaYIP3 gene encoding the orthologue of the Saccharomyces cerevisiae YIP3 Rab-GDI complex dissociation factor expresses two polypeptides, one of which, the long form, is produced through a programmed translation frameshift. Inactivation of PaYIP3 results in slightly delayed growth associated with modification in repartition of fruiting body on the thallus, along with reduced ascospore production on wood. Long and short forms of PaYIP3 are expressed in the mycelium, while only the short form appears expressed in the maturing fruiting body (perithecium). The frameshift has been conserved over the evolution of the Pezizomycotina, lasting for over 400 million years, suggesting that it has an important role in the wild.

在模式真菌粪生柄孢壳（Podospora anserina）中，编码酿酒酵母（Saccharomyces cerevisiae）YIP3型Rab-GDI复合物解离因子同源物的PaYIP3基因可表达两种多肽，其中长型多肽通过程序性翻译移码产生。PaYIP3基因失活会导致生长轻度延迟，伴随营养体上子实体分布模式改变，同时使木质基质上的子囊孢子产量降低。PaYIP3的长、短两种亚型均可在菌丝体中表达，而在成熟子实体（子囊壳，perithecium）中仅检测到短亚型的表达。该移码事件在盘菌亚门（Pezizomycotina）的演化历程中得以保留，保守时长已超4亿年，提示其在自然环境中具有重要生物学功能。