Fig. 5
Activation of the epothilone gene cluster under the control of copper-inducible promoter. a The yield of epothilones A and B in mutants YL1616, YL1624 (25 μM CuSO4), YL1624 (120 μM), YL1624 (200 μM) and M. xanthus ZE9. b RT-qPCR analysis of the expression levels of seven genes of mutants YL1616, YL1624 (25 μM), YL1624 (120 μM), YL1624 (200 μM). The expressions of the seven genes in M. xanthus ZE9 at 48 h of incubation were set as 1, and the expressions of the seven genes of mutant strains were the relative expressions on them. The error bars represent the standard deviation of three independent experiments. For statistical analysis between wild type strain and mutant strains, ** and * mean p < 0.01 and p < 0.05, respectively