PKA CONTROLS MRNA GRANULES DURING QUIESCENCE AND CELL CYCLE RESUMPTION IN Saccharomyces cerevisiae

CLARA SOLARI; PAULA PORTELA

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Localization of an mRNA to a specific site is a highly regulated process that modulates its translation. In order to analyze the localization of different mRNAs in quiescent cells, we performed confocal microscopy over strains carrying the m-TAG system for ENO2, PDC1, MFA2, TIF1, TDP1 and VNX1 mRNAs. These mRNAs are accumulated in 1-2 foci during quiescence. When cells are re-fed by addition of fresh medium for 30 minutes, TDP1 and VNX1 mRNAs granules are disassembled; but ENO2, PDC1, MFA2, and TIF1 mRNA granules increase to 2-6 granules per cell. The co-localization of mRNA granules and stress granules or P-bodies presents differences between the mRNAs. Analysis of mRNA localization in strains harboring each PKA catalytic subunit deletion, indicated that each PKA isoform controls specific mRNA granule formation. To assess the presence of active translation sites we used immunofluorescence over cells treated with puromycin. A proportion of the puromycin-marked sites of protein synthesis overlap with both ENO2 and TIF1 mRNA granules during quiescence. After fresh medium addition, translationally active mRNA granules increase in an mRNA specific manner. Therefore, our results suggest that PKA controls mRNA storage into cytoplasmic foci during quiescence; and that these mRNA granules could regulate localized protein translation.