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Background  Due to the important role of rifamycin in curing tuberculosis infection, the study on rifamycin has never been stopped. Although RifZ, which locates within the rifamycin biosynthetic cluster, has recently been characterized as a pathway-specific regulator for rifamycin biosynthesis, little is known about the regulation of rifamycin export.    Results  In this work, we proved that the expression of the rifamycin efflux pump (RifP) was regulated by RifQ, a TetR-family transcriptional regulator. Deletion of  rifQ  had little impact on bacterial growth, but resulted in improved rifamycin production, which was consistent with the reverse transcription PCR results that RifQ negatively regulated  rifP ’s transcription. With electrophoretic mobility shift assay and DNase I Footprinting assay, RifQ was found to directly bind to the promoter region of  rifP , and a typical inverted repeat was identified within the RifQ-protected sequences. The transcription initiation site of  rifP  was further characterized and found to be upstream of the RifQ binding sites, well explaining the RifQ-mediated repression of  rifP ’s transcription in vivo. Moreover, rifamycin B (the end product of rifamycin biosynthesis) remarkably decreased the DNA binding affinity of RifQ, which led to derepression of rifamycin export, reducing the intracellular concentration of rifamycin B as well as its toxicity against the host.    Conclusions  Here, we proved that the export of rifamycin B was repressed by RifQ in  Amycolatopsis mediterranei , and the RifQ-mediated repression could be specifically relieved by rifamycin B, the end product of rifamycin biosynthesis, based on which a feedback model was proposed for regulation of rifamycin export. With the findings here, one could improve the antibiotic yield by simply inactivating the negative regulator of the antibiotic transporter.    Electronic supplementary material  The online version of this article (10.1186/s12934-018-0863-5) contains supplementary material, which is available to authorized users.

A feedback regulatory model for RifQ-mediated repression of rifamycin export in Amycolatopsis mediterranei