Figure 4. IUE-mediated expression of caHSF1 recapitulates the physiologically relevant levels of HSF1 activation elicited by environmental challenges.

(a) Representative images of Hsp70 mRNA expression in pCAGIG (control) or pCAGIG-caHSF1 electroporated cells. The plasmids were introduced into mouse frontal cortices by IUE at E14. The electroporated cells were dissociated 24 h post-electroporation, and plated on culture dishes. 3 h later, Hsp70 mRNAs were detected by smFISH. (b) The graph shows the number of Hsp70 mRNA particles in the control- and caHSF1-electroporated cells. caHSF1 overexpression results in significantly higher numbers of Hsp70 mRNAs compared with the control (*P<0.001 by Mann-Whitney U-Test). Importantly, these numbers fall in the range of the top 5% and 20% of those induced by EtOH and MeHg, respectively (Fig. 1 and Supplementary Fig. 1). Scale bar, 0.02 mm.