Circadian regulation of cytoplasmic mRNA-granules

LESCANO JI; GUIDO ME; GARBARINO PICO E

Huerta Grande

Congreso; II Reunión Conjunta de Neurociencias (II RCN): XXV Reunión anual de la SAN y XII TAN; 2010

Sociedad Argentina de Investigaciones en Neurociencias (SAN) y Taller Argentino de Neurociencias (TAN)

Gene expression is modulated by clocks, 5-20% of the mRNAs expressed in a given tissue show daily oscillations. Presumably, this is largely generated by changes in the transcription of those genes; however, the relative importance of mRNA post-transcriptional processing has not been established. Stress granules (SG) and P-bodies are cytoplasmic subdomains involved in the regulation of translation, mRNA decay and storage. They are formed by RNA and a number of factors involved in mRNA cytoplasmic processing. Considering that some of the SG and P-body components are expressed under circadian basis, we have analyzed whether these foci show rhythmic changes. NIH3T3 cells were synchronized by serum shock and fixed after 7, 14, 21, and 28 h. SG and P-bodies were detected by ICC. P-body per cell (number) showed fluctuations peaking 28 h after synchronization, and reaching highest areas 14 h after the shock. We applied arsenite (oxidative stress) for inducing SG. The number of SG/cell did not change through time; however the area and perimeter of them showed daily variations with peak 14 h after serum shock. Further studies will be carried out with other markers to confirm these results; however they suggest that these foci, or a subpopulation of them, are regulated by a circadian clock.