1
|
D'Agostino PM, Al-Sinawi B, Mazmouz R, Muenchhoff J, Neilan BA, Moffitt MC. Identification of promoter elements in the Dolichospermum circinale AWQC131C saxitoxin gene cluster and the experimental analysis of their use for heterologous expression. BMC Microbiol 2020; 20:35. [PMID: 32070286 PMCID: PMC7027233 DOI: 10.1186/s12866-020-1720-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/03/2020] [Indexed: 01/06/2023] Open
Abstract
Background Dolichospermum circinale is a filamentous bloom-forming cyanobacterium responsible for biosynthesis of the paralytic shellfish toxins (PST), including saxitoxin. PSTs are neurotoxins and in their purified form are important analytical standards for monitoring the quality of water and seafood and biomedical research tools for studying neuronal sodium channels. More recently, PSTs have been recognised for their utility as local anaesthetics. Characterisation of the transcriptional elements within the saxitoxin (sxt) biosynthetic gene cluster (BGC) is a first step towards accessing these molecules for biotechnology. Results In D. circinale AWQC131C the sxt BGC is transcribed from two bidirectional promoter regions encoding five individual promoters. These promoters were identified experimentally using 5′ RACE and their activity assessed via coupling to a lux reporter system in E. coli and Synechocystis sp. PCC 6803. Transcription of the predicted drug/metabolite transporter (DMT) encoded by sxtPER was found to initiate from two promoters, PsxtPER1 and PsxtPER2. In E. coli, strong expression of lux from PsxtP, PsxtD and PsxtPER1 was observed while expression from Porf24 and PsxtPER2 was remarkably weaker. In contrast, heterologous expression in Synechocystis sp. PCC 6803 showed that expression of lux from PsxtP, PsxtPER1, and Porf24 promoters was statistically higher compared to the non-promoter control, while PsxtD showed poor activity under the described conditions. Conclusions Both of the heterologous hosts investigated in this study exhibited high expression levels from three of the five sxt promoters. These results indicate that the majority of the native sxt promoters appear active in different heterologous hosts, simplifying initial cloning efforts. Therefore, heterologous expression of the sxt BGC in either E. coli or Synechocystis could be a viable first option for producing PSTs for industrial or biomedical purposes.
Collapse
Affiliation(s)
- Paul M D'Agostino
- School of Science, Western Sydney University, Sydney, NSW, Australia.,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Biosystems Chemistry, Department of Chemistry, Technische Universität München, Garching, Germany.,Technical Biochemistry, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Bakir Al-Sinawi
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Rabia Mazmouz
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Julia Muenchhoff
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia. .,School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia.
| | | |
Collapse
|
2
|
Functional identification and regulatory analysis of Δ6-fatty acid desaturase from the oleaginous fungus Mucor sp. EIM-10. Biotechnol Lett 2016; 39:453-461. [DOI: 10.1007/s10529-016-2268-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/05/2016] [Indexed: 01/10/2023]
|
3
|
Hu J, Zhao L, Yang M. A GntR family transcription factor positively regulates mycobacterial isoniazid resistance by controlling the expression of a putative permease. BMC Microbiol 2015; 15:214. [PMID: 26474554 PMCID: PMC4609117 DOI: 10.1186/s12866-015-0556-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 10/08/2015] [Indexed: 01/13/2023] Open
Abstract
Background Bacteria use transcriptional regulation to respond to environmental stresses. Specifically, exposure to antibacterial drugs is deemed to be an atypical stress, and altering transcriptional regulation in response to such stress can increase bacterial drug resistance. However, only a few transcription factors that regulate drug resistance have been reported. Results In the present study, a GntR family transcription factor, encoded by the MSMEG_0535 (Ms0535) gene, was shown to be an isoniazid (INH) resistance regulator in Mycobacterium smegmatis. When the Ms0535 gene was overexpressed, cells showed a significant increase in INH resistance. First, the interaction between Ms0535 and its own promoter was determined, and a conserved 26-bp palindromic DNA binding motif was identified using electrophoretic mobility shift and DNaseI footprinting assays. Second, quantitative reverse transcription-PCR assays showed that Ms0535 acted as a transcriptional activator, and positively regulated its own expression, as well as that of a permease encoded by the MSMEG_0534 (Ms0534) gene. Similar to the case for the Ms0535 gene, a recombinant Ms0534-overexpressing strain also exhibited increased INH resistance compared with the wild-type strain. Furthermore, we showed that Ms0535 and Ms0534 deletion strains were more sensitive to INH than the wild-type strain. Interestingly, overexpressing Ms0534 in the Ms0535 deletion strain enhanced its INH resistance. In contrast, the Ms0534 deletion strain was still sensitive to INH even when Ms0535 was overexpressed. These findings suggest that Ms0534 is an effector protein that affects INH resistance in M. smegmatis. Conclusions In summary, the GntR transcriptional regulator Ms0535 positively regulates INH resistance by transcriptionally regulating the expression of the Ms0534 permease in M. smegmatis. These results improve our understanding of the role of transcriptional regulation in INH drug resistance in mycobacteria. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0556-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Jialing Hu
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Lei Zhao
- National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Min Yang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| |
Collapse
|
4
|
Kurdrid P, Phuengcharoen P, Yutthanasirikul R, Roytrakul S, Paemanee A, Cheevadhanarak S, Hongsthong A. Identification of regulatory regions and regulatory protein complexes of the Spirulina desD gene under temperature stress conditions: role of thioredoxin as an inactivator of a transcriptional repressor GntR under low-temperature stress. Biochem Cell Biol 2012; 90:621-35. [PMID: 22788703 DOI: 10.1139/o2012-017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In the present study, electrophoretic mobility shift assays were used to identify temperature responsive elements in the 5' upstream region (5' UTR) of the Spirulina desD gene. Overlapping, synthetic oligonucleotides of both sense and anti-sense strands that spanned the entire 5' UTR of the gene were analyzed. The responsive DNA-binding protein complexes were identified using liquid chromatography-tandem mass spectrometry. The results indicated that the cold-responsive elements were located at -453 to -247, -197 to -151, -105 to -76, and -50 to -1, whereas the low-temperature specific regulatory regions were located at -372 to -352. Moreover, the heat-responsive elements were located at -347 to -243, -197 to -151, and -124 to -1, whereas the high-temperature specific elements were located between -130 to -101 and -30 to -1. In terms of regulatory protein complexes under the two stress conditions, Trx was only detected in the low-temperature responsive protein complex, and divalent cations were essential for the binding of the protein complex to the regulatory elements. Furthermore, Trx was shown to play a critical role as a reducing agent that inactivates the Spirulina desD repressor, GntR. Consequently, the desD gene expression is induced under the low-temperature condition.
Collapse
Affiliation(s)
- Pavinee Kurdrid
- Biochemical Engineering and Pilot Plant Research and Development Unit, National Center for Genetic Engineering and Biotechnology, King Mongkut's University of Technology-Thonburi (Bangkhuntien), 49 Soi Theintalay 25, Thakham, Bangkhuntien, Bangkok 10150, Thailand
| | | | | | | | | | | | | |
Collapse
|
5
|
Song LY, Lu WX, Hu J, Zhang Y, Yin WB, Chen YH, Hao ST, Wang BL, Wang RRC, Hu ZM. Identification and functional analysis of the genes encoding Delta6-desaturase from Ribes nigrum. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:1827-38. [PMID: 20231328 PMCID: PMC2852672 DOI: 10.1093/jxb/erq051] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 02/09/2010] [Accepted: 02/16/2010] [Indexed: 05/18/2023]
Abstract
Gamma-linolenic acid (gamma-linolenic acid, GLA; C18:3 Delta(6, 9, 12)) belongs to the omega-6 family and exists primarily in several plant oils, such as evening primrose oil, blackcurrant oil, and borage oil. Delta(6)-desaturase is a key enzyme involved in the synthesis of GLA. There have been no previous reports on the genes encoding Delta(6)-desaturase in blackcurrant (Ribes nigrum L.). In this research, five nearly identical copies of Delta(6)-desaturase gene-like sequences, named RnD8A, RnD8B, RnD6C, RnD6D, and RnD6E, were isolated from blackcurrant. Heterologous expression in Saccharomyces cerevisiae and/or Arabidopsis thaliana confirmed that RnD6C/D/E were Delta(6)-desaturases that could use both alpha-linolenic acids (ALA; C18:3 Delta(9,12,15)) and linoleic acid (LA; C18:2 Delta(9,12)) precursors in vivo, whereas RnD8A/B were Delta(8)-sphingolipid desaturases. Expression of GFP tagged with RnD6C/D/E showed that blackcurrant Delta(6)-desaturases were located in the mitochondrion (MIT) in yeast and the endoplasmic reticulum (ER) in tobacco. GC-MS results showed that blackcurrant accumulated GLA and octadecatetraenoic acids (OTA; C18:4 Delta(6,9,12,15)) mainly in seeds and a little in other organs and tissues. RT-PCR results showed that RnD6C and RnD6E were expressed in all the tissues at a low level, whereas RnD6D was expressed at a high level only in seeds, leading to the accumulation of GLA and OTA in seeds. This research provides new insights to our understanding of GLA synthesis and accumulation in plants and the evolutionary relationship of this class of desaturases, and new clues as to the amino acid determinants which define precise enzyme activity.
Collapse
Affiliation(s)
- Li-Ying Song
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Wan-Xiang Lu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400716, China
| | - Jun Hu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
| | - Yan Zhang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
| | - Wei-Bo Yin
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
| | - Yu-Hong Chen
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
| | - Shan-Ting Hao
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
| | - Bai-Lin Wang
- Horticulture Division, Heilongjiang Agriculture Academy, Harbin 150069, China
| | - Richard R-C Wang
- USDA-ARS, FRRL, Utah State University, Logan, UT 84322-6300, USA
| | - Zan-Min Hu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing 100101, China
| |
Collapse
|
6
|
Kurdrid P, Phuengcharoen P, Cheevadhanarak S, Tanticharoen M, Hongsthong A. Identification of a heat shock-responsive cis-acting DNA sequence and its transcriptional regulator: Their roles in the expression of the Spirulina-desD gene in response to heat stress. J Biosci Bioeng 2009; 109:205-10. [PMID: 20159564 DOI: 10.1016/j.jbiosc.2009.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 09/01/2009] [Accepted: 09/01/2009] [Indexed: 11/19/2022]
Abstract
This study addresses the importance of a heat-shock-responsive cis-acting DNA element and its transcriptional regulator, which play key roles in the regulation of the Spirulina-desD gene on exposure to high temperatures. Temperature response analysis studies showed that the AT-rich region that is located between nt -98 to -80 of the Spirulina-desD gene promoter serves as a binding site for its transcriptional regulator. LC-MS/MS analysis of the DNA-binding protein complex revealed that the amino acid sequences of the bound proteins were homologous to those of several proteins, including a DNA-binding protein, heat shock protein-90 (Hsp90 or HtpG), GroEL and various protein kinases. In addition, western blot analysis indicated that the chaperones GroEL and Hsp90 and a dephosphorylation reaction played a role in the response to elevated temperatures. We conclude that the regulatory DNA segments and the corresponding regulatory binding proteins are distinct for each particular stress condition. This is true, irrespective of whether the regulatory mechanisms that govern the expression of the cold- and heat-regulated desD gene depend on similar phosphorylation- and dephosphorylation-dependent conformational changes that modulate the association of the co-chaperone.
Collapse
Affiliation(s)
- Pavinee Kurdrid
- Biochemical Engineering and Pilot Plant Research and Development Unit, National Center for Genetic Engineering and Biotechnology, King Mongkut's University of Technology-Thonburi (Bangkhuntien), 83 Moo 8, Thakham, Bangkhuntien, Bangkok 10150, Thailand
| | | | | | | | | |
Collapse
|