Oscilaciones en gránulos citoplasmáticos de mRNA en fibroblastos wt y Bmal1-/-

GARBARINO PICO EDUARDO; SAAD LUCÍA FLORENCIA; MALCOLM MELISA

Córdoba

Jornada; VIII Jornadas de Posgrado de la Facultad de Ciencias Químicas, II Jornadas de Ciencia y Tecnología; 2018

Facultad de Ciencias Químicas, UNC

: Stress granules (SGs) are microscopically visible aggregates of messenger ribonucleoproteins that assemble when cells undergo stress. In these membraneless organelles the mRNA can be stored for being translated again later when stress is relieved. Processing bodies (PBs) are also cytoplasmic mRNA granules enriched in factors involved in transcript degradation, storage and translational repression. Considering that the stress response is circadianly regulated in several organisms, and that we found in circadian expression databases that some components of SGs and PBs fluctuate over time, we hypothesized that these foci oscillate. We show that the number and area of SGs induced by oxidative stress, as well as the PB number, exhibit daily oscillations in NIH3T3 cells. TIA-1, a protein with a prion-like domain that induces SG nucleation, is also expressed rhythmically. To test whether SG temporal changes were controlled by the transcriptional translational feedback loops (TTFLs) that form the molecular circadian clock, we analyzed SGs in wt and Bmal1-/- fibroblasts. Unexpectedly, we found oscillations in the number, area and signal intensity of SGs in both genotypes. The period and phase of the oscillations were similar in both cell lines, but the amplitude was higher in Bmal1-/- cells, suggesting that the TTFLs modulate the strength of the response at different times. We thought that the SG rhythms could be generated by redox or translational rhythms that have been shown previously in Bmal1-/- cells