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. Author manuscript; available in PMC: 2014 Jun 6.
Published in final edited form as: Cell. 2013 Jun 6;153(6):1366–1378. doi: 10.1016/j.cell.2013.05.015

Figure 6. A PHA-4 – dependent transcriptional feedback coordinates cell-non-autonomous hsp90 expression.

Figure 6

(A) Total mRNA levels of hsp-1 (constitutive hsp70), hs-inducible hsp70 (C12C8.1 and F44E5.4), small heat shock protein hsp16 (hsp-16.2) and hsp90 in HSP90 overexpression lines at 20°C relative to wild type. The slightly increased hsp levels in the HSP90bwm may be indicative of the higher sensitivity of muscle cells to proteostatic perturbation, in line with the observations on tissue-specific hsp90 knockdown, where the HSR is primarily induced in the bodywall muscle. (B) Organismal hsp90 expression in HSP90 overexpression lines is independent of hsf-1. hsp90 mRNA levels in control (EV) and animals fed with hsf-1 RNAi. Whereas hsp90 expression in wild type is hsf-1 dependent, RNAi-mediated knockdown of hsf-1 leaves organismal hsp90 levels in HSP90bwm, HSP90int or HSP90neuro unchanged. (C) pha-4 RNAi decreases elevated hsp90 expression in the overexpression lines. (D) hsp90p::GFP reporter expression in myosin (ts, e1157) or paramyosin (ts, e1402) mutants is reduced during pha-4 RNAi when compared to control RNAi (EV). Scalebar = 50 μm. (E) pha-4 activity is increased in the HSP90 overexpression lines. mRNA levels of pha-4 regulated genes sod-1, sod-2, sod-4 and sod-5 are induced in eat-2(ad1113) mutants, HSP90bwm, HSP90int and HSP90neuro animals relative to wild type. *P-value < 0.05. **P-value < 0.02. (F) pha-4 mRNA expression levels in eat-2 and HSP90 overexpression lines are upreguated, relative to the wild type control. *P-value < 0.05. (G) pha-4 activity in intestinal cells of eat-2(ad1113), HSP90bwm, HSP90int and HSP90neuro animals relative to wild type. **P-value < 0.02. (H) pha-4 mRNA expression levels are induced in the intestines of eat-2 mutants and HSP90int (=signaling tissue), but not in the intestines of HSP90bwm or HSP90neuro (=recipient tissue). *P-value < 0.05. (n.s. = not significant). (A – H) All bar graphs represent combined mean values of three independent experiments (3 biological replicates) (means ± s.e.m.). See also Figure S6.