P-bodies and Stress Granules are regulated by Circadian Clocks

LESCANO JI; PUSTERLA JM; GUIDO ME; GARBARINO PICO E

Congreso; XXVI Congreso Anual de la Sociedd Argentina de Investigación en Neurociencias (SAN); 2011

SAN

Gene expression is modulated by clocks at different points, includding the posttranscriptional level. 5-20% of the mRNAs expressed in a given tissue show daily changes in their levels. Whereas transcriptional oscillations have been extensivelely analyzed, the circadian regulation of posttranscriptional events has been less studied. In the cytoplasm, messenger ribonucleoprotein (mRNP) complexes can assemble into cytoplasmic mRNP granules as P-bodies and stress granules (SG). These foci are involved in the regulation of mRNA decay and storage, as well as translation. We have analyzed whether these foci are circandianly regulated. NIH3T3 cells were synchronized by serum shock. SG and P-bodies were detected at different times by ICC with antibodies against eIF3 and GE-1 respectively. P-body per cell (number) showed fluctuations peaking 28 h after synchronization and reaching highest areas 14 h after the shock. The arsenite-induced SG also showed temporal changes through time. We have also analyzed the temporal expression of factors that could be responsible for the generation of these rhythms. We found some RNA-binding proteins whose transcripts exhibit temporal changes. Our results suggest that P-bodies and SGs, or a subpopulation of them, are regulated by circadian clocks.