A distinct inner nuclear membrane proteome in Saccharomyces cerevisiae gametes

The inner nuclear membrane (INM) proteome regulates gene expression, chromatin organization, and nuclear transport, however, it is poorly understood how changes in INM protein composition contribute to developmentally regulated processes, such as gametogenesis. Using a split-GFP complementation system, we compared the distribution of all C-terminally tagged transmembrane proteins in Saccharomyces cerevisiae in gametes to that of mitotic cells. Gametes contain a distinct INM proteome needed to complete gamete formation, including expression of genes linked to cell wall biosynthesis, lipid biosynthetic and metabolic pathways, protein degradation and unknown functions. Based on the inheritance pattern, INM components are made de novo in the gametes. Whereas mitotic cells show a strong preference for proteins with small extraluminal domains, gametes do not exhibit this size preference likely due to the changes in the nuclear permeability barrier during gametogenesis.