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Ishinishi R, Matsuura H, Tanaka S, Nozawa S, Tanada K, Kawashita N, Fujiyama K, Miyasaka H, Hirata K. Isolation and characterization of a stress-responsive gene encoding a CHRD domain-containing protein from a halotolerant green alga. Gene 2018; 640:14-20. [PMID: 29017964 DOI: 10.1016/j.gene.2017.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/12/2017] [Accepted: 10/06/2017] [Indexed: 11/18/2022]
Abstract
The genetic basis of stress resistance in extremophilic microalgae is not well studied. In this study, a gene of unknown function, the cluster58 or CL58 gene, was identified from the halotolerant green alga Chlamydomonas W80 and characterized. The CL58 gene encodes a protein containing a domain of unknown function, the CHRD domain, and a putative secretory signaling sequence at its N-terminus. The levels of CL58 mRNA increased in response to high copper levels and low temperatures. When the CL58 gene was heterologously expressed as a fusion gene with the NanoLuc luciferase gene in Chlamydomonas reinhardtii, a majority of the NanoLuc activity was detected in the culture medium compared with that in the intracellular fraction. A mutagenic analysis revealed that the putative secretory signaling sequence was sufficient for the secretion of the CL58-NanoLuc fusion protein. In addition, we expressed the protein encoded by the CL58 gene in Escherichia coli; the recombinant, soluble protein was then purified. In summary, we identified a novel gene from C. W80 that appears to encode a stress-responsive, CHRD domain-containing secreted protein.
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Affiliation(s)
- Ryo Ishinishi
- Applied Environmental Biology Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hideyuki Matsuura
- Applied Environmental Biology Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Satoshi Tanaka
- The Kansai Electric Power Co., Inc., Advanced Technology Laboratory, Keihanna Engineering Center, 1-7 Seika-cho, Souraku-gun, Kyoto 619-0237, Japan
| | - Saaya Nozawa
- Applied Environmental Biology Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Keisuke Tanada
- Applied Environmental Biology Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Norihito Kawashita
- Pharmainformatics and Pharmacometrics Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuhito Fujiyama
- International Center for Biotechnology, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hitoshi Miyasaka
- Department of Applied Life Science, Sojo University, 4-22-1 Ikeda, Nishiku, Kumamoto 860-0082, Japan
| | - Kazumasa Hirata
- Applied Environmental Biology Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
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