Temporal dynamics of Stress Granules

GARBARINO PICO E; GUIDO ME

Congreso; XLVIII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2012

Gene expression changes in response to stress; this includes the formation of stress granules (SG), foci where many transcripts are stored during stress, releasing translational machinery for the synthesis of stress response factors. SG are cytoplasmic aggregates of silenced mRNAs and a number of RNA processing factors. Since stress response is modulated by biological clocks, and anumber of SG components display circadian rhythms, we hypothesized that SG could be temporarily regulated.We synchronized NIH3T3 cells and harvested them at different times. SG were induced by oxidative stress and analyzed by ICC with an anti-eIF3 antibody. We found that SG number and signal intensity present temporal changes.Area and perimeter showed only modest variations. The expression of eIF3 did not change.We found no changes in phosphorylated eIF2alpha, a protein involved in SG assembly. Then we analyzed by RT-qPCR the temporal expression of several RNA-binding proteins that are in SG and could be involved in the temporal changes observed. Interesting, , and transcripts presented temporal changes in their levels. TIA1 protein has been implicated in SG assembly; we found that its levels oscillate. LARK, which regulates the translation of the clock protein PER1 and circadian behavior, also presented temporal variations. Our results showed thatSGare temporarily regulated.