P-bodies and stress granules are linked spatially and functionally [14], [17] and [18], and we found in a previous study that treatment with GA affected the integrity of stress granules; i.e., upon GA treatment, the size and subcellular localization of the stress granules were altered, and eIF4E and 4E-T were selectively lost from stress granules [9]. Consequently, we investigated stress granules in RA-treated
VX-689 by staining the cells with anti-YB-1 and anti-eIF4E antibodies, because we showed clearly in the earlier report that stress granules contain both YB-1 and eIF4E proteins [9]. In the control cells, upon heat shock both YB-1 and eIF4E localized to stress granules, which formed mainly in the perinuclear region ( Fig. 3A, RA?). However, although stress granules still assembled in RA-treated cells upon exposure to heat shock, they were slightly smaller and distributed more uniformly throughout the cytoplasm than in the control cells ( Fig. 3A, YB-1). In addition, eIF4E was not detected in stress granules that were stained by anti-YB-1
antibodies in RA-treated cells ( Fig. 3A, RA+). These observations were similar to our previous findings in cells that were treated with GA [9]. Thus, treatment with RA does not abolish the assembly of stress granules but does disrupt the incorporation of eIF4E into these assembled granules.
