title: Characterizing yeast promoters used in Kluyveromyces marxianus.
abstract: Fermentation at higher temperatures can potentially reduce the cooling cost in large-scale fermentation and reduce the contamination risk. Thus, the thermotolerant yeast, Kluyveromyces marxianus, which can grow and ferment at elevated temperatures, is a promising biotechnological tool for future applications. However, the promoters used in K. marxianus are not well characterized, especially at elevated temperatures, which is important in efficient metabolic pathway construction. In this study, six constitutive promoters (P(TDH3), P(PGK), and P(ADH1) from both Saccharomyces cerevisiae and K. marxianus) were evaluated in K. marxianus through the heterologous expression of the KlLAC4, GUSA, and SH BLE genes at various temperatures, with various carbon sources and oxygen conditions. The expression was evaluated at the transcription and protein level using real-time PCR and protein activity determination to eliminate the effect of heterologous protein stability. While the transcription of all the promoters decreased at higher temperatures, the order of their promoting strength at various temperatures with glucose as the carbon source was P(KmPGK) > P(KmTDH3) > P(ScPGK) > P(ScTDH3) > P(KmADH1) > P(ScADH1). When glycerol or xylose was supplied as the carbon source at 42 °C, the order of promoter strength was P(KmPGK) > P(ScPGK) > P(KmADH1) > P(ScADH1) > P(ScTDH3) > P(KmTDH3). The promoter activity of P TDH3 decreased significantly, while the promoter activity of both of the P(ADH1) promoters increased. Oxygen conditions had non-significant effect. The results of this study provide important information for fine-tuned pathway construction for the metabolic engineering of K. marxianus.
authors.affiliation: School of Life Science, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China.|Hefei National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei, 230026, Anhui, People's Republic of China.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.affiliation: School of Life Science, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China.|Hefei National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei, 230026, Anhui, People's Republic of China.
authors.forename: Shenglin
authors.initials: S
authors.lastname: Hu
authors.affiliation: School of Life Science, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China.|Hefei National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei, 230026, Anhui, People's Republic of China.
authors.forename: Songli
authors.initials: S
authors.lastname: Zhu
authors.affiliation: School of Life Science, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China.|Hefei National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei, 230026, Anhui, People's Republic of China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.affiliation: School of Life Science, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China.|Hefei National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei, 230026, Anhui, People's Republic of China.|Department of Biology and Biochemistry, University of Houston, Houston, 77004-5001, USA.
authors.forename: Xiaolian
authors.initials: X
authors.lastname: Gao
authors.affiliation: School of Life Science, University of Science and Technology of China, Hefei, 230027, Anhui, People's Republic of China. hjiong@ustc.edu.cn.|Hefei National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei, 230026, Anhui, People's Republic of China. hjiong@ustc.edu.cn.
authors.forename: Jiong
authors.initials: J
authors.lastname: Hong
mesh_terms: D015870:Gene Expression / Q000528:radiation effects*; D020869:Gene Expression Profiling; D007716:Kluyveromyces / Q000235:genetics* / Q000528:radiation effects*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013696:Temperature
chemical_list: D011994:Recombinant Proteins
keywords: Carbon source; Elevated temperature; Kluyveromyces marxianus; Promoter