Stress granules and Processing bodies oscillate in mammalian fibroblasts.

MALCOLM M; SAAD LF; PENAZZI LG; GARBARINO PICO E

Congreso; XXXIII Congreso Anual de la SAN; 2018

Sociedad Argentina de Investigaciones en Neurociencias (SAN)

Stress granules (SGs) and processing bodies (PBs) are cytoplasmic membraneless organelles in which ribonucleoprotein complexes accumulates. SGs are formed by translational machinery components, like minor ribosomal subunits and translation initiation factors. SGs assemble when cells undergoes stress. PBs are formed by factors involved in mRNA translation inhibition and decay. It has been observed that several components of both SGs and PBs are rhythmically expressed, in a circadian fashion, thus 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 t st 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. Bmal1 is an essential and non-redundant component of TTFLs. 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.