Heat-shock-induced constitutive active ATF6 specifically induces reporter expression. (A) Schematic of the hsp70:GAL4 construct used to induce ubiquitous expression of UAS constructs mosaically expressing either caATF6, XBP1s or ATF4 with a T2A self-cleaving peptide and mCherry. (B,C) Representative images (B) and quantification of reporter expression (C) from embryos expressing hsp70:GAL4 and 5XATF6RE:d2GFP transgenes that were injected with mCherry-tagged UAS plasmids to overexpress caATF6 (left), XBP1s (middle) or ATF4 (right) compared to injection control (Inj Ctrl) embryos injected with all components except overexpression plasmids. 2-dpf embryos were heat shocked and confocal images were captured 12 h later. Quantification of the head region (dashed line) revealed a significant increase in 5XATF6RE:d2GFP intensity with caATF6 overexpression (P=0.0067), a significant decrease with XBP1s overexpression (P=0.0182) and no significant change with ATF4 overexpression (P=0.1055) compared to the injection control. *P≤0.05; **P≤0.01; ns, P>0.05; unpaired Student's t-test. All error bars are s.e.m. Scale bars: 1 mm.
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