Jinyang Li1,2, Qian Liu1, Jingen Li1, Liangcai Lin1, Xiaolin Li1,3, Yongli Zhang1,2, Chaoguang Tian4,5,6. 1. Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. 2. University of Chinese Academy of Sciences, Beijing, 100049, China. 3. State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China. 4. Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. tian_cg@tib.cas.cn. 5. University of Chinese Academy of Sciences, Beijing, 100049, China. tian_cg@tib.cas.cn. 6. National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China. tian_cg@tib.cas.cn.
Abstract
BACKGROUND: Low- and high-affinity glucose transport system is a conserved strategy of microorganism to cope with environmental glucose fluctuation for their growth and competitiveness. In Neurospora crassa, the dual-affinity glucose transport system consists of a low-affinity glucose transporter GLT-1 and two high-affinity glucose transporters HGT-1/HGT-2, which play diverse roles in glucose transport, carbon metabolism, and cellulase expression regulation. However, the regulation of this dual-transporter system in response to environmental glucose fluctuation is not yet clear. RESULTS: In this study, we report that a regulation module consisting of a downstream transcription factor COL-26 and an upstream non-transporting glucose sensor RCO-3 regulates the dual-affinity glucose transport system in N. crassa. COL-26 directly binds to the promoter regions of glt-1, hgt-1, and hgt-2, whereas RCO-3 is an upstream factor of the module whose deletion mutant resembles the Δcol-26 mutant phenotypically. Transcriptional profiling analysis revealed that Δcol-26 and Δrco-3 mutants had similar transcriptional profiles, and both mutants had impaired response to a glucose gradient. We also showed that the AMP-activated protein kinase (AMPK) complex is involved in regulation of the glucose transporters. AMPK is required for repression of glt-1 expression in starvation conditions by inhibiting the activity of RCO-3. CONCLUSIONS: RCO-3 and COL-26 form an external-to-internal module that regulates the glucose dual-affinity transport system. Transcription factor COL-26 was identified as the key regulator. AMPK was also involved in the regulation of the dual-transporter system. Our findings provide novel insight into the molecular basis of glucose uptake and signaling in filamentous fungi, which may aid in the rational design of fungal strains for industrial purposes.
BACKGROUND: Low- and high-affinity glucose transport system is a conserved strategy of microorganism to cope with environmental glucose fluctuation for their growth and competitiveness. In Neurospora crassa, the dual-affinity glucose transport system consists of a low-affinity glucose transporter GLT-1 and two high-affinity glucose transporters HGT-1/HGT-2, which play diverse roles in glucose transport, carbon metabolism, and cellulase expression regulation. However, the regulation of this dual-transporter system in response to environmental glucose fluctuation is not yet clear. RESULTS: In this study, we report that a regulation module consisting of a downstream transcription factor COL-26 and an upstream non-transporting glucose sensor RCO-3 regulates the dual-affinity glucose transport system in N. crassa. COL-26 directly binds to the promoter regions of glt-1, hgt-1, and hgt-2, whereas RCO-3 is an upstream factor of the module whose deletion mutant resembles the Δcol-26 mutant phenotypically. Transcriptional profiling analysis revealed that Δcol-26 and Δrco-3 mutants had similar transcriptional profiles, and both mutants had impaired response to a glucose gradient. We also showed that the AMP-activated protein kinase (AMPK) complex is involved in regulation of the glucose transporters. AMPK is required for repression of glt-1 expression in starvation conditions by inhibiting the activity of RCO-3. CONCLUSIONS:RCO-3 and COL-26 form an external-to-internal module that regulates the glucose dual-affinity transport system. Transcription factor COL-26 was identified as the key regulator. AMPK was also involved in the regulation of the dual-transporter system. Our findings provide novel insight into the molecular basis of glucose uptake and signaling in filamentous fungi, which may aid in the rational design of fungal strains for industrial purposes.
Authors: Astrid R Mach-Aigner; Jimmy Omony; Birgit Jovanovic; Anton J B van Boxtel; Leo H de Graaff Journal: Appl Environ Microbiol Date: 2012-02-17 Impact factor: 4.792
Authors: Elsy N Tamayo; Adela Villanueva; Alinda A Hasper; Leo H de Graaff; Daniel Ramón; Margarita Orejas Journal: Fungal Genet Biol Date: 2008-03-10 Impact factor: 3.495
Authors: Thomas Portnoy; Antoine Margeot; Rita Linke; Lea Atanasova; Erzsébet Fekete; Erzsébet Sándor; Lukas Hartl; Levente Karaffa; Irina S Druzhinina; Bernhard Seiboth; Stéphane Le Crom; Christian P Kubicek Journal: BMC Genomics Date: 2011-05-27 Impact factor: 3.969