Transcription factor; part of the gene cluster that mediates the biosynthesis of 1233A, a natural compound known as an inhibitor of HMG-CoA synthase in the mevalonate pathway and with antibacterial and antifungal activities (PubMed:32139880). Involved in hygromycin B-induced transcriptional control of the cluster (PubMed:32139880). Expression is increased upon exposure to hygromycin B. Impairs the ability to produce 1233A and 1233B.