Fig. 4

Light sensitivity in relation to different potential light-sensing mechanisms. a Light sensitivity of cells lacking Pox1 (pox1Δ) or overexpressing POX1 (PGK-POX1) as assayed by the spot-test assay and growth curves. A representative result from two independent experiments is shown (see Additional file 5 for individual values). b Light sensitivity of cells lacking Tsa1 (tsa1Δ) as assayed by the spot-test assay and growth curves. Values are averages from two independent experiments, and error bars represent SD. c Yap1-GFP localizes to the nucleus in response to light exposure. Left: cells exposed to 460 μW constant light exposure for 1 min wt or gpx3Δ. Right: cells before exposure to light. d Quantification of Yap1-GFP nuclear localization. The data presented represent averages of localization scored in individual cells, n = 246 (wt) and n = 152 (gpx3∆). e Generation times for the indicated opsin-like single deletion (hsp30Δ, mrh1Δ, yro2Δ), double deletion as well as a triple mutant strain. As a positive control the light sensitive hog1Δ strain was used. Values represent averages of at least three independent experiments, and error bars indicate SD (see Additional file 5 for individual values). Only the hog1∆ strain showed a significant (Student t test, p < 0.05) difference to the wt strain (indicated with *). f The Msn2-GFP nuclear localization during light exposure in two respiratory deficient mutants; the rho- and the mip1∆ strain. Values are averages from analysis of individual cells; n = 112 (wt), n = 98 (mip1∆), and n = 58 (rho⁰). MIP1 encodes an essential component of the RNA polymerase for transcription of genes in the mitochondrial genome. Msn2-GFP nuclear localization trajectories for a rho⁰ and a mip1Δ strain indicate that respiratory activity, and the corresponding H₂O₂ generation in the mitochondria, is not required for the Msn2 nuclear localization response to light