| Saccharopolyspora erythraea is used for the industrial-scale production of the antibiotic erythromycin A, derivatives of which play a vital role in medicine. Because of the extensive application of erythromycin and its derivatives, there are a lot of studies on S. erythraea to improve the erythromycin yield.In this work, we sequenced the whole genome of a high-producing strain (HL3168 E3) obtained by random mutagenesis and screening from the wide-type strain NRRL 23338, and examined time-series expression profiles of both strains, which enables the comparative analysis of high-producing strain and wide-type strain at both the genomic level and the transcriptomic level. We observed a large number of genetic variants including 60 insertions, 46 deletions and 584 single nucleotide variations (SNV) in E3 in comparison with NRRL23338. The analysis of time series transcriptomic data indicated that the genes involved in erythromycin biosynthesis and feeder pathways were significantly up-regulated, and nitrogen-metabolism was repressed during the 60 hours time-course. Several potential regulators were then proposed by integration analysis of genomic and transcriptomic data. These findings help to understand the global regulation mechanisms of erythromycin biosynthesis in S. erythraea, providing useful clues for genetic and metabolic engineering in the future.And then we focused on the transcription factor GlnR involved in nitrogen metabolism and find out how it works.We obtained GlnR protein by E. coli expression system, and GlnR was found to bind to 12 promoter regions of operons involved in nitrogen metabolism using EMSA. Based on the above experiment results, we predicted possible motifs of GlnR. What we have done provided a new breakthrough to explore the mechanism of erythromycin biosynthesis. |
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