title: Pgas, a Low-pH-Induced Promoter, as a Tool for Dynamic Control of Gene Expression for Metabolic Engineering of Aspergillus niger.
abstract: The dynamic control of gene expression is important for adjusting fluxes in order to obtain desired products and achieve appropriate cell growth, particularly when the synthesis of a desired product drains metabolites required for cell growth. For dynamic gene expression, a promoter responsive to a particular environmental stressor is vital. Here, we report a low-pH-inducible promoter, Pgas, which promotes minimal gene expression at pH values above 5.0 but functions efficiently at low pHs, such as pH 2.0. First, we performed a transcriptional analysis ofAspergillus niger, an excellent platform for the production of organic acids, and we found that the promoter Pgasmay act efficiently at low pH. Then, a gene for synthetic green fluorescent protein (sGFP) was successfully expressed by Pgasat pH 2.0, verifying the results of the transcriptional analysis. Next, Pgaswas used to express thecis-aconitate decarboxylase (cad) gene ofAspergillus terreusinA. niger, allowing the production of itaconic acid at a titer of 4.92 g/liter. Finally, we found that Pgasstrength was independent of acid type and acid ion concentration, showing dependence on pH only.IMPORTANCEThe promoter Pgascan be used for the dynamic control of gene expression inA. nigerfor metabolic engineering to produce organic acids. This promoter may also be a candidate tool for genetic engineering.
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.|Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Yin
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
authors.forename: Hyun-Dong
authors.initials: HD
authors.lastname: Shin
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.|Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Jianghua
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.|Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China longliu@jiangnan.edu.cn.|Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Long
authors.initials: L
authors.lastname: Liu
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D001234:Aspergillus niger / Q000235:genetics / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000235:genetics*; D060847:Metabolic Engineering / Q000379:methods*; D011401:Promoter Regions, Genetic; D013386:Succinates / Q000378:metabolism*
chemical_list: D013386:Succinates; D002262:Carboxy-Lyases; C018742:aconitate decarboxylase; C005229:itaconic acid
keywords: Aspergillus niger; dynamic gene expression; itaconic acid; low-pH-inducible promoter; metabolic engineering