Fig. 4.

P54 RNA helicase cytoplasmic granules exhibit the properties of stress granules. (A–D,I–L) Anti-P54 immunostaining in 24 hpf WT zebrafish embryos. (E–H,M–P) Anti-TIAL-1 immunostaining as a marker for stress granules in 24 hpf WT embryos. (A–H) Some embryos were treated for 2 h with cycloheximide to block the formation of stress granules. (I–P) Puromycin was added (also for 2 h) to some of the embryos to enhance the assembly of stress granules. (A,B,E,F,I,J,M,N) Fish embryos were maintained at 28.5°C during cycloheximide and puromycin treatments or (C,D,G,H,K,L,O,P) at 37°C. After treatments and immunostaining, fluorescence signals were visualized by confocal microscopy. Arrowheads point to smaller granules (P-body size), and arrows point to larger stress granules. Anti-P54 and anti-TIAL-1 antibodies are both shown in green and DAPI nuclei staining in blue. At the bottom left of each image, the percentage of embryos showing the same immune reaction pattern is indicated, with the total number of embryos treated in parentheses.