Fig. 1From: Multi-component gene network design as a survival strategy in diverse environmentsa Network architecture built by the GAL2, GAL3, GAL4, and GAL80 regulatory genes. The red lines denote the four-stage signaling cascade. The galactose-bound state of Gal3p is denoted by Gal3p*. Pointed and blunt red arrows reflect activation and inhibition, respectively. The dashed blue arrows denote feedback loops established by Gal2p, Gal3p and Gal80p. The dashed red arrow represents the constitutive expression of the Gal4 proteins. The double red arrows denote translocation of Gal80p and Gal3p* between cytoplasm and nucleus. b Illustration of the fitness metric. The strain under investigation is mixed with a reference strain, allowed to equilibrate and then grown for 48Â h. The fitness value is calculated from the population ratio of the two strains at the beginning and end of the growth period as shownBack to article page