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Wu H, Chu Z, Zhang W, Zhang C, Ni J, Fang H, Chen Y, Wang Y, Zhang L, Zhang B. Transcriptome-guided target identification of the TetR-like regulator SACE_5754 and engineered overproduction of erythromycin in Saccharopolyspora erythraea. J Biol Eng 2019; 13:11. [PMID: 30697347 PMCID: PMC6346578 DOI: 10.1186/s13036-018-0135-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 12/17/2018] [Indexed: 11/13/2022] Open
Abstract
Background Erythromycin A (Er-A) produced by the actinomycete Saccharopolyspora erythraea is an important antibiotic extensively used in human medicine. Dissecting of transcriptional regulators and their target genes associated with erythromycin biosynthesis is crucial to obtain erythromycin overproducer strains through engineering of relevant regulatory elements in S. erythraea. Results Here, we identified a TetR family transcriptional regulator (TFR), SACE_5754, negatively controlling erythromycin production. SACE_5754 indirectly repressed the transcription of ery cluster and cannot regulate itself and its adjacent gene SACE_5753. RNA-seq coupled with EMSAs and qRT-PCR was performed to identify the targets of SACE_5754, and confirmed that transcription of SACE_0388 (encoding a pyruvate, water diknase), SACE_3599 (encoding an antibiotic resistance macrolide glycosyltransferase) and SACE_6149 (encoding a FAD-binding monooxygenase) were directly repressed by SACE_5754. A consensus palindromic sequence TYMAGG-n2/n4/n11-KKTKRA (Y: C/T, M: A/C, K: T/G, R: A/G) was proved to be essential for SACE_5754 binding using DNase I footprinting and EMSAs. During the three target genes of SACE_5754, SACE_0388 and SACE_6149 exhibited the positive effect on erythromycin production. Overexpression of either SACE_0388 or SACE_6149 in ∆SACE_5754 further increased the Er-A production. By engineering the industrial strain S. erythraea WB with deletion of SACE_5754 combined with overexpression of either SACE_0388 or SACE_6149, Er-A production in WB∆SACE_5754/pIB139–0388 and WB∆SACE_5754/pIB139–6149 was successively increased by 42 and 30% compared to WB. Co-overexpression of SACE_0388 and SACE_6149 in WB∆SACE_5754 resulted in enhanced Er-A production by 64% relative to WB. In a 5-L fermenter, WB∆SACE_5754/pIB139–0388-6149 produced 4998 mg/L Er-A, a 48% increase over WB. Conclusion We have identified a TFR, SACE_5754, as a negative regulator of erythromycin biosynthesis, and engineering of SACE_5754 and its target genes, SACE_0388 and SACE_6149, resulted in enhanced erythromycin production in both wild-type and industrial S. erythraea strains. The strategy demonstrated here may be valuable to facilitate the manipulation of transcriptional regulators and their targets for production improvement of antibiotics in industrial actinomycetes. Electronic supplementary material The online version of this article (10.1186/s13036-018-0135-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hang Wu
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Zuling Chu
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Wanxiang Zhang
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Chi Zhang
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Jingshu Ni
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Heshi Fang
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Yuhong Chen
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Yansheng Wang
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
| | - Lixin Zhang
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China.,2State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237 China
| | - Buchang Zhang
- 1School of Life Sciences, Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601 China
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TetR-Type Regulator SLCG_2919 Is a Negative Regulator of Lincomycin Biosynthesis in Streptomyces lincolnensis. Appl Environ Microbiol 2018; 85:AEM.02091-18. [PMID: 30341075 DOI: 10.1128/aem.02091-18] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/01/2018] [Indexed: 12/21/2022] Open
Abstract
Lincomycin A (Lin-A) is a widely used antibacterial antibiotic fermented by Streptomyces lincolnensis However, the transcriptional regulatory mechanisms underlying lincomycin biosynthesis have seldom been investigated. Here, we first identified a TetR family transcriptional regulator (TFR), SLCG_2919, which negatively modulates lincomycin biosynthesis in S. lincolnensis LCGL. SLCG_2919 was found to specifically bind to promoter regions of the lincomycin biosynthetic gene cluster (lin cluster), including 25 structural genes, three resistance genes, and one regulatory gene, and to inhibit the transcription of these genes, demonstrating a directly regulatory role in lincomycin biosynthesis. Furthermore, we found that SLCG_2919 was not autoregulated, but directly repressed its adjacent gene, SLCG_2920, which encodes an ATP/GTP binding protein whose overexpression increased resistance against lincomycin and Lin-A yields in S. lincolnensis The precise SLCG_2919 binding site within the promoter region of SLCG_2920 was determined by a DNase I footprinting assay and by electrophoretic mobility shift assays (EMSAs) based on base substitution mutagenesis, with the internal 10-nucleotide (nt) AT-rich sequence (AAATTATTTA) shown to be essential for SLCG_2919 binding. Our findings indicate that SLCG_2919 is a negative regulator for controlling lincomycin biosynthesis in S. lincolnensis The present study improves our understanding of molecular regulation for lincomycin biosynthesis.IMPORTANCE TetR family transcriptional regulators (TFRs) are generally found to regulate diverse cellular processes in bacteria, especially antibiotic biosynthesis in Streptomyces species. However, knowledge of their function in lincomycin biosynthesis in S. lincolnensis remains unknown. The present study provides a new insight into the regulation of lincomycin biosynthesis through a TFR, SLCG_2919, that directly modulates lincomycin production and resistance. Intriguingly, SLCG_2919 and its adjoining gene, SLCG_2920, which encodes an ATP/GTP binding protein, were extensively distributed in diverse Streptomyces species. In addition, we revealed a new TFR binding motif, in which SLCG_2919 binds to the promoter region of SLCG_2920, dependent on the intervening AT-rich sequence rather than on the flanking inverted repeats found in the binding sites of other TFRs. These insights into transcriptional regulation of lincomycin biosynthesis by SLCG_2919 will be valuable in paving the way for genetic engineering of regulatory elements in Streptomyces species to improve antibiotic production.
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Hong M, Huang M, Chu J, Zhuang Y, Zhang S. Impacts of proline on the central metabolism of an industrial erythromycin-producing strain Saccharopolyspora erythraea via 13 C labeling experiments. J Biotechnol 2016; 231:1-8. [DOI: 10.1016/j.jbiotec.2016.05.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
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Wu H, Wang Y, Yuan L, Mao Y, Wang W, Zhu L, Wu P, Fu C, Müller R, Weaver DT, Zhang L, Zhang B. Inactivation of SACE_3446, a TetR family transcriptional regulator, stimulates erythromycin production in Saccharopolyspora erythraea. Synth Syst Biotechnol 2016; 1:39-46. [PMID: 29062926 PMCID: PMC5640589 DOI: 10.1016/j.synbio.2016.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 01/08/2016] [Accepted: 01/10/2016] [Indexed: 11/29/2022] Open
Abstract
Erythromycin A is a widely used antibiotic produced by Saccharopolyspora erythraea; however, its biosynthetic cluster lacks a regulatory gene, limiting the yield enhancement via regulation engineering of S. erythraea. Herein, six TetR family transcriptional regulators (TFRs) belonging to three genomic context types were individually inactivated in S. erythraea A226, and one of them, SACE_3446, was proved to play a negative role in regulating erythromycin biosynthesis. EMSA and qRT-PCR analysis revealed that SACE_3446 covering intact N-terminal DNA binding domain specifically bound to the promoter regions of erythromycin biosynthetic gene eryAI, the resistant gene ermE and the adjacent gene SACE_3447 (encoding a long-chain fatty-acid CoA ligase), and repressed their transcription. Furthermore, we explored the interaction relationships of SACE_3446 and previously identified TFRs (SACE_3986 and SACE_7301) associated with erythromycin production. Given demonstrated relatively independent regulation mode of SACE_3446 and SACE_3986 in erythromycin biosynthesis, we individually and concomitantly inactivated them in an industrial S. erythraea WB. Compared with WB, the WBΔ3446 and WBΔ3446Δ3986 mutants respectively displayed 36% and 65% yield enhancement of erythromycin A, following significantly elevated transcription of eryAI and ermE. When cultured in a 5 L fermentor, erythromycin A of WBΔ3446 and WBΔ3446Δ3986 successively reached 4095 mg/L and 4670 mg/L with 23% and 41% production improvement relative to WB. The strategy reported here will be useful to improve antibiotics production in other industrial actinomycete.
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Affiliation(s)
- Hang Wu
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Yansheng Wang
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Li Yuan
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Yongrong Mao
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Weiwei Wang
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Lin Zhu
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Panpan Wu
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Chengzhang Fu
- CAS Key Laboratory of Pathogenic Microbiology & Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,Helmholtz Institute for Pharmaceutical Research, Helmholtz Centre for Infection Research and Department of Pharmaceutical Biotechnology, Saarland University, P.O. Box 15115, 66041 Saarbrücken, Germany
| | - Rolf Müller
- Helmholtz Institute for Pharmaceutical Research, Helmholtz Centre for Infection Research and Department of Pharmaceutical Biotechnology, Saarland University, P.O. Box 15115, 66041 Saarbrücken, Germany
| | - David T Weaver
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
| | - Lixin Zhang
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China.,CAS Key Laboratory of Pathogenic Microbiology & Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Buchang Zhang
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei 230601, China
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Reciprocal Regulation of GlnR and PhoP in Response to Nitrogen and Phosphate Limitations in Saccharopolyspora erythraea. Appl Environ Microbiol 2015; 82:409-20. [PMID: 26519391 DOI: 10.1128/aem.02960-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/22/2015] [Indexed: 11/20/2022] Open
Abstract
Nitrogen and phosphate source sensing, uptake, and assimilation are essential for the growth and development of microorganisms. In this study, we demonstrated that SACE_6965 encodes the phosphate regulator PhoP, which controls the transcription of genes involved in phosphate metabolism in the erythromycin-producing Saccharopolyspora erythraea. We found that PhoP and the nitrogen regulator GlnR both regulate the transcription of glnR as well as other nitrogen metabolism-related genes. Interestingly, both GlnR- and PhoP-binding sites were identified in the phoP promoter region. Unlike the nonreciprocal regulation of GlnR and PhoP observed in Streptomyces coelicolor and Streptomyces lividans, GlnR negatively controls the transcription of the phoP gene in S. erythraea. This suggests that GlnR directly affects phosphate metabolism and demonstrates that the cross talk between GlnR and PhoP is reciprocal. Although GlnR and PhoP sites in the glnR and phoP promoter regions are located in close proximity to one another (separated by only 2 to 4 bp), the binding of both regulators to their respective region was independent and noninterfering. These results indicate that two regulators could separately bind to their respective binding sites and control nitrogen and phosphate metabolism in response to environmental changes. The reciprocal cross talk observed between GlnR and PhoP serves as a foundation for understanding the regulation of complex primary and secondary metabolism in antibiotic-producing actinomycetes.
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Capturing the target genes of BldD in Saccharopolyspora erythraea using improved genomic SELEX method. Appl Microbiol Biotechnol 2014; 99:2683-92. [PMID: 25549616 DOI: 10.1007/s00253-014-6255-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 11/17/2014] [Accepted: 11/18/2014] [Indexed: 10/24/2022]
Abstract
BldD (SACE_2077), a key developmental regulator in actinomycetes, is the first identified transcriptional factor in Saccharopolyspora erythraea positively regulating erythromycin production and morphological differentiation. Although the BldD of S. erythraea binds to the promoters of erythromycin biosynthetic genes, the interaction affinities are relatively low, implying the existence of its other target genes in S. erythraea. Through the genomic systematic evolution of ligands by exponential enrichment (SELEX) method that we herein improved, four DNA sequences of S. erythraea A226, corresponding to the promoter regions of SACE_0306 (beta-galactosidase), SACE_0811 (50S ribosomal protein L25), SACE_3410 (fumarylacetoacetate hydrolase), and SACE_6014 (aldehyde dehydrogenase), were captured with all three BldD concentrations of 0.5, 1, and 2 μM, while the previously identified intergenic regions of eryBIV-eryAI and ermE-eryCI plus the promoter region of SACE_7115, the amfC homolog for aerial mycelium formation, could be captured only when the BldD's concentration reached 2 μM. Electrophoretic mobility shift assay (EMSA) analysis indicated that BldD specifically bound to above seven DNA sequences, and quantitative real-time PCR (qRT-PCR) assay showed that the transcriptional levels of the abovementioned target genes decreased when bldD was disrupted in A226. Furthermore, SACE_7115 and SACE_0306 in A226 were individually inactivated, showing that SACE_7115 was predominantly involved in aerial mycelium formation, while SACE_0306 mainly controlled erythromycin production. This study provides valuable information for better understanding of the pleiotropic regulator BldD in S. erythraea, and the improved method may be useful for uncovering regulatory networks of other transcriptional factors.
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Wu H, Chen M, Mao Y, Li W, Liu J, Huang X, Zhou Y, Ye BC, Zhang L, Weaver DT, Zhang B. Dissecting and engineering of the TetR family regulator SACE_7301 for enhanced erythromycin production in Saccharopolyspora erythraea. Microb Cell Fact 2014; 13:158. [PMID: 25391994 PMCID: PMC4258057 DOI: 10.1186/s12934-014-0158-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 10/23/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Saccharopolyspora erythraea was extensively utilized for the industrial-scale production of erythromycin A (Er-A), a macrolide antibiotic commonly used in human medicine. Yet, S. erythraea lacks regulatory genes in the erythromycin biosynthetic gene (ery) cluster, hampering efforts to enhance Er-A production via the engineering of regulatory genes. RESULTS By the chromosome gene inactivation technique based on homologous recombination with linearized DNA fragments, we have inactivated a number of candidate TetR family transcriptional regulators (TFRs) and identified one TFR (SACE_7301) positively controlling erythromycin biosynthesis in S. erythraea A226. qRT-PCR and EMSA analyses demonstrated that SACE_7301 activated the transcription of erythromycin biosynthetic gene eryAI and the resistance gene ermE by interacting with their promoter regions with low affinities, similar to BldD (SACE_2077) previously identified to regulate erythromycin biosynthesis and morphological differentiation. Therefore, we designed a strategy for overexpressing SACE_7301 with 1 to 3 extra copies under the control of PermE* in A226. Following up-regulated transcriptional expression of SACE_7301, eryAI and ermE, the SACE_7301-overexpressed strains all increased Er-A production over A226 proportional to the number of copies. Likewise, when SACE_7301 was overexpressed in an industrial S. erythraea WB strain, Er-A yields of the mutants WB/7301, WB/2×7301 and WB/3×7301 were respectively increased by 17%, 29% and 42% relative to that of WB. In a 5 L fermentor, Er-A accumulation increased to 4,230 mg/L with the highest-yield strain WB/3×7301, an approximately 27% production improvement over WB (3,322 mg/L). CONCLUSIONS We have identified and characterized a TFR, SACE_7301, in S. erythraea that positively regulated erythromycin biosynthesis, and overexpression of SACE_7301 in wild-type and industrial S. erythraea strains enhanced Er-A yields. This study markedly improves our understanding of the unusual regulatory mechanism of erythromycin biosynthesis, and provides a novel strategy towards Er-A overproduction by engineering transcriptional regulators of S. erythraea.
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Affiliation(s)
- Hang Wu
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China.
| | - Meng Chen
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China.
| | - Yongrong Mao
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China.
| | - Weiwei Li
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China.
| | - Jingtao Liu
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China. .,Beijing Institute of Cell Biotechnology, Beijing, 100043, China.
| | - Xunduan Huang
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China.
| | - Ying Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science & Technology, Shanghai, 200237, China.
| | - Bang-Ce Ye
- State Key Laboratory of Bioreactor Engineering, East China University of Science & Technology, Shanghai, 200237, China.
| | - Lixin Zhang
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China. .,CAS Key Laboratory of Pathogenic Microbiology & Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - David T Weaver
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China.
| | - Buchang Zhang
- Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei, 230601, China.
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Wu P, Pan H, Zhang C, Wu H, Yuan L, Huang X, Zhou Y, Ye BC, Weaver DT, Zhang L, Zhang B. SACE_3986, a TetR family transcriptional regulator, negatively controls erythromycin biosynthesis in Saccharopolyspora erythraea. ACTA ACUST UNITED AC 2014; 41:1159-67. [DOI: 10.1007/s10295-014-1449-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 04/17/2014] [Indexed: 11/29/2022]
Abstract
Abstract
Erythromycin, a medically important antibiotic, is produced by Saccharopolyspora erythraea. Unusually, the erythromycin biosynthetic gene cluster lacks a regulatory gene, and the regulation of its biosynthesis remains largely unknown. In this study, through gene deletion, complementation and overexpression experiments, we identified a novel TetR family transcriptional regulator SACE_3986 negatively regulating erythromycin biosynthesis in S. erythraea A226. When SACE_3986 was further inactivated in an industrial strain WB, erythromycin A yield of the mutant was increased by 54.2 % in average compared with that of its parent strain, displaying the universality of SACE_3986 as a repressor for erythromycin production in S. erythraea. qRT-PCR analysis indicated that SACE_3986 repressed the transcription of its adjacent gene SACE_3985 (which encodes a short-chain dehydrogenase/reductase), erythromycin biosynthetic gene eryAI and the resistance gene ermE. As determined by EMSA analysis, purified SACE_3986 protein specifically bound to the intergenic region between SACE_3985 and SACE_3986, whereas it did not bind to the promoter regions of eryAI and ermE. Furthermore, overexpression of SACE_3985 in A226 led to enhanced erythromycin A yield by at least 32.6 %. These findings indicate that SACE_3986 is a negative regulator of erythromycin biosynthesis, and the adjacent gene SACE_3985 is one of its target genes. The present study provides a basis to increase erythromycin production by engineering of SACE_3986 and SACE_3985 in S. erythraea.
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Affiliation(s)
- Panpan Wu
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
| | - Hui Pan
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
| | - Congming Zhang
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
| | - Hang Wu
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
| | - Li Yuan
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
| | - Xunduan Huang
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
| | - Ying Zhou
- grid.28056.39 0000000121634895 State Key Laboratory of Bioreactor Engineering East China University of Science and Technology 200237 Shanghai China
| | - Bang-ce Ye
- grid.28056.39 0000000121634895 State Key Laboratory of Bioreactor Engineering East China University of Science and Technology 200237 Shanghai China
| | - David T Weaver
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
| | - Lixin Zhang
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
- grid.9227.e 0000000119573309 CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology Chinese Academy of Sciences 100101 Beijing China
| | - Buchang Zhang
- grid.252245.6 0000000100854987 Institute of Health Sciences, School of Life Sciences Anhui University Hefei 230601 China
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Kirm B, Magdevska V, Tome M, Horvat M, Karničar K, Petek M, Vidmar R, Baebler S, Jamnik P, Fujs Š, Horvat J, Fonovič M, Turk B, Gruden K, Petković H, Kosec G. SACE_5599, a putative regulatory protein, is involved in morphological differentiation and erythromycin production in Saccharopolyspora erythraea. Microb Cell Fact 2013; 12:126. [PMID: 24341557 PMCID: PMC3878487 DOI: 10.1186/1475-2859-12-126] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 12/10/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Erythromycin is a medically important antibiotic, biosynthesized by the actinomycete Saccharopolyspora erythraea. Genes encoding erythromycin biosynthesis are organized in a gene cluster, spanning over 60 kbp of DNA. Most often, gene clusters encoding biosynthesis of secondary metabolites contain regulatory genes. In contrast, the erythromycin gene cluster does not contain regulatory genes and regulation of its biosynthesis has therefore remained poorly understood, which has for a long time limited genetic engineering approaches for erythromycin yield improvement. RESULTS We used a comparative proteomic approach to screen for potential regulatory proteins involved in erythromycin biosynthesis. We have identified a putative regulatory protein SACE_5599 which shows significantly higher levels of expression in an erythromycin high-producing strain, compared to the wild type S. erythraea strain. SACE_5599 is a member of an uncharacterized family of putative regulatory genes, located in several actinomycete biosynthetic gene clusters. Importantly, increased expression of SACE_5599 was observed in the complex fermentation medium and at controlled bioprocess conditions, simulating a high-yield industrial fermentation process in the bioreactor. Inactivation of SACE_5599 in the high-producing strain significantly reduced erythromycin yield, in addition to drastically decreasing sporulation intensity of the SACE_5599-inactivated strains when cultivated on ABSM4 agar medium. In contrast, constitutive overexpression of SACE_5599 in the wild type NRRL23338 strain resulted in an increase of erythromycin yield by 32%. Similar yield increase was also observed when we overexpressed the bldD gene, a previously identified regulator of erythromycin biosynthesis, thereby for the first time revealing its potential for improving erythromycin biosynthesis. CONCLUSIONS SACE_5599 is the second putative regulatory gene to be identified in S. erythraea which has positive influence on erythromycin yield. Like bldD, SACE_5599 is involved in morphological development of S. erythraea, suggesting a very close relationship between secondary metabolite biosynthesis and morphological differentiation in this organism. While the mode of action of SACE_5599 remains to be elucidated, the manipulation of this gene clearly shows potential for improvement of erythromycin production in S. erythraea in industrial setting. We have also demonstrated the applicability of the comparative proteomics approach for identifying new regulatory elements involved in biosynthesis of secondary metabolites in industrial conditions.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Hrvoje Petković
- Acies Bio, d,o,o, Tehnološki park 21, SI-1000, Ljubljana, Slovenia.
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