Hyperosmotic stress delays and dampens mating transcription.

<p>Transcriptional activation (β-galactosidase activity) was measured spectrofluorometrically every 30 min in (A) wild-type, (B) <i>hog1</i>Δ, and (C) <i>hog1^K52R</i> cells transformed with a plasmid containing a pheromone-inducible reporter (<i>FUS1</i>-lacZ). Transcription was induced by the addition of 10 µM α factor, 10 µM α factor+0.5 M KCl, 10 µM α factor+0.75 M KCl, or 10 µM α factor+1 M KCl. Data are the mean ± SE of four individual colonies measured in quadruplicate and presented as percentage of wild-type maximum. Transcriptional activation (GFP expression) was measured by fluorescence microscopy in individual wild-type cells with an integrated pheromone-inducible reporter (<i>FUS1-GFP</i>). (D) Representative images of GFP expression in G1 cells stimulated by the addition of 10 µM α factor or 10 µM α factor+0.5 M KCl. Color spectrum indicates GFP pixel intensity as calculated using ImageJ. (E) Scatter plot of GFP fluorescence (average pixel intensity/cell area) in individual cells stimulated with 10 µM α factor or 10 µM α factor+0.5 M KCl. Insert is the average GFP intensity from the population of individual cells in (E), error bars indicate 95% CI.