FIG 7 .

Model of regulation of antimycin biosynthesis. The top panel displays the relative locations of the antimycin and candicidin gene clusters in the S. albus S4 chromosome. In the bottom panel, FscRI activates the transcription of antBA and antCDE, which results in production of the core AntC/AntD NRPS/PKS megasynthase and production of the discrete acyltransferase AntB and σ^AntA, which in turn activates the transcription of the ketoreductase gene antM and nine genes (antFGHIJKLNO) required for the biosynthesis and activation of the 3-formamidosalicylate precursor utilized by AntC. σ^AntA does not possess a cognate anti-σ factor and instead appears to be inactivated by the ClpXP protease.