Abstract
Saccharopolyspora erythraea produces a large number of secondary metabolites with biological activities, including erythromycin. Elucidation of the mechanisms through which the production of these secondary metabolites is regulated may help to identify new strategies for improved biosynthesis of erythromycin. In this paper, we describe the systematic prediction and analysis of small non-coding RNAs (sRNAs) in S. erythraea, with the aim to elucidate sRNA-mediated regulation of secondary metabolite biosynthesis. In silico and deep-sequencing technologies were applied to predict sRNAs in S. erythraea. Six hundred and forty-seven potential sRNA loci were identified, of which 382 cis-encoded antisense RNA are complementary to protein-coding regions and 265 predicted transcripts are located in intergenic regions. Six candidate sRNAs (sernc292, sernc293, sernc350, sernc351, sernc361, and sernc389) belong to four gene clusters (tpc3, pke, pks6, and nrps5) that are involved in secondary metabolite biosynthesis. Deep-sequencing data showed that the expression of all sRNAs in the strain HL3168 E3 (E3) was higher than that in NRRL23338 (M), except for sernc292 and sernc361 expression. The relative expression of six sRNAs in strain M and E3 were validated by qRT-PCR at three different time points (24, 48, and 72 h). The results showed that, at each time point, the transcription levels of sernc293, sernc350, sernc351, and sernc389 were higher in E3 than in M, with the largest difference observed at 72 h, whereas no signals for sernc292 and sernc361 were detected. sernc293, sernc350, sernc351, and sernc389 probably regulate iron transport, terpene metabolism, geosmin synthesis, and polyketide biosynthesis, respectively. The major significance of this study is the successful prediction and identification of sRNAs in genomic regions close to the secondary metabolism-related genes in S. erythraea. A better understanding of the sRNA-target interaction would help to elucidate the complete range of functions of sRNAs in S. erythraea, including sRNA-mediated regulation of erythromycin biosynthesis.
Highlights
Saccharopolyspora erythraea is a gram-positive filamentous bacterium that was originally identified as Streptomyces erythraeus, but later assigned to the genus Saccharopolyspora [1]
Six candidate small non-coding RNAs (sRNAs) were found to be associated with 3 gene clusters that are involved in secondary metabolite biosynthesis (Table 2)
Antibiotic-producing microorganisms are still poorly understood in this bacterium, this information is essential to the design of rational strategies for industrial strain improvement
Summary
Saccharopolyspora erythraea is a gram-positive filamentous bacterium that was originally identified as Streptomyces erythraeus, but later assigned to the genus Saccharopolyspora [1]. Studies focused on secondary metabolites of S. erythraea may provide a better understanding of the biosynthesis and regulation of erythromycin. Wild-type actinomycete strains are subjected to multiple rounds of random mutagenesis and selection to obtain mutants that overproduce the desired secondary metabolite for industrial production. In 2007, the genome of S. erythraea was completely sequenced and annotated [3], thereby facilitating the expedited optimization of such actinomycete strains for production. Within the last few years, small non-coding RNAs (sRNAs) have been implicated as important post-transcriptional regulators in a variety of adaptive cellular and developmental processes, as well as during virulence in bacteria [7,8,9,10]. Studies have suggested that sRNAs play an important role in the regulation of secondary metabolites
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
