Fig. 1.

Δopi1 deletion increases antibody production through increased ER size. a Growth of the two background strains was measured in complex (a) and synthetic media (b) at 30 °C. Used media are indicated in the graphs. Upper panels represent growth under non-inducing conditions, lower panels growth under inducing conditions. When antibody expression was not induced (a and b, upper panels), growth behavior of wild-type (wt) and Δopi1 strains was similar. While antibody expression was induced (a and b, lower panels), growth of Δopi1 mutant was reduced. c A notched box-plot presentation of all the measured antibody concentrations for the background strains shows that antibody secretion was considerably more efficient for Δopi1 in all temperatures. The number of measurement points used for each box is 82 or 84. d Fluorescence of GFP under an UPR-responsive promoter was recorded in wt and Δopi1. The background corrected RFU-values remain much lower for Δopi1. Highest GFP fluorescence of wt was two times higher per OD compared to Δopi1