Dynamics of ectopic stress granules in FRSN and EA.hy926 cells

Abstract

Stress granules (SGs) are cytoplasmic ribonucleoprotein associates that are formed when the cap-dependent translation is attenuated in eukaryotic cells during cellular stress caused by elevated temperature, hypoxia, ultraviolet light, etc. SGs can also spontaneously assemble upon overexpression of their protein components. In this work, the SG components, TIA1 and G3BP1 proteins, were expressed in FRSN and EA.hy926 cells as a fusion protein with fluorescent EGFP, which enabled visualization of artificial SGs. We found spontaneous assembly and stable persistence of SG following the transfection. However, the frequency of SG dissociation increased with increasing time after the transfection. Under the ER stress induced by dithiothreitol, the number of cells with SGs increased. However, that was a generally late nucleation of SGs. This we assumed was related to secondary stress factors that had joined during oER stress. Given the important role of SGs in cell survival, monitoring of SGs provides additional information on the mechanisms of cellular stress response in FRSN and EA.hy926 cells.