Ribosome pausing at the AT-rich codons regulates the protein expression of secondary metabolite gene clusters in the Streptomyces tsukubaensis NRRL 18488

Streptomyces tsukubaensis NRRL 18488 is the preferred strain for the production of immunosuppressant agent tacrolimus (FK506). To take full advantage of its genetic potential, systematic understanding of secondary metabolism and related regulatory mechanisms is highly demanded. Here, to this end, we complete its 7.9 Mbp linear genome sequence followed by integrating with multi-omics measurements. With accurate reannotation of FK506 gene cluster, total 2,389 transcription start sites were determined by using primary transcriptome analysis. Integrated analysis of transcriptome and translatome data revealed that secondary metabolic gene clusters, especially FK506 cluster, undergo translational control with decrease in translational efficiency according to the growth. Furthermore, we demonstrated that SD motif has little correlation with ribosome pausing but AT-rich codons delay the translational elongation. Strong ribosome pausing was observed in the rare TTA codon in FK506 cluster. This comprehensive genome-scale analysis provides insight to the translational regulation of secondary metabolism in S. tsukubaensis. Overall design: Transcription abundance and ribosomal profiling analysis of Streptomyces tsukubaensis according to the growth phase