Fig. 6: Genes silenced by dsRNA in parents commonly recover from silencing in descendants.
From: Mating can initiate stable RNA silencing that overcomes epigenetic recovery
a Six target genes containing the same gfp sequence were exposed to the same sources of control RNAi or gfp RNAi. P0 animals were fed dsRNA for 24 h, and the P0 animals and their untreated descendants for up to five generations (F1–F5) were analysed. Representative images highlight the germline (green outline) of P0 animals. Numbers of descendant generations that show silencing are indicated. Note that sun-1::gfpvar is also present in the animal with PH::gfp, but is not silenced because its gfpvar sequence only has <14-nt of continuous homology with the gfp-dsRNA used for feeding RNAi. Scale bars indicate 50 µm. b P0 animals expressing T were exposed to control RNAi (P0 control RNAi) or gfp-dsRNA (P0 gfp RNAi) for 24 h and silencing was analysed in P0 animals and in their untreated descendants. Upon gfp RNAi, P0 and F1 animals were each pooled for imaging but subsequent generations each descending from one P0 ancestor (P0-1, P0-2, or P0-3) were imaged as individual isolates. All generations shown were scored by imaging except F2s, which were scored by eye. While one isolate showed TEI, the other two isolates recovered expression (epigenetic recovery). As indicated with a schematic, the sequence of gfp dsRNA matches the exons of gfp coding sequence. c gtbp-1::gfp animals were fed gfp-dsRNA (black) for one, two or three consecutive generations and their untreated progeny (gray) in a wild-type (eri-1(+)) or eri-1(−) background were scored for expression of GFP. d gtbp-1::gfp hermaphrodites in wild-type (met-2(+) and heri-1(+)), met-2(−) or heri-1(−) backgrounds were fed gfp-dsRNA for 24 h and untreated descendants in subsequent generations (F1–F7) were scored as in Supplementary Fig. 8c. Feeding RNAi of other strains was performed concurrently, thus data for gtbp-1::gfp here is the same as in Supplementary Fig. 8c. In heri-1(-) animals, the statistical difference between P0 and F1–F2 is due to increased silencing, but that between P0 and F3–F7 is due to decreased silencing. Most animals fed control RNAi and descendants showed bright expression of GFP (except 2 out of 45 F5 descendants and 1 out of 37 F7 descendants of heri-1(-) animals that showed dim expression). Number of animals scored (n) are indicated. Asterisks indicate P < 0.05 using χ2 test. Also see Supplementary Fig. 8. Source data are provided as a Source Data file.
