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Im SH, Lepetit B, Mosesso N, Shrestha S, Weiss L, Nymark M, Roellig R, Wilhelm C, Isono E, Kroth PG. Identification of promoter targets by Aureochrome 1a in the diatom Phaeodactylum tricornutum. J Exp Bot 2024; 75:1834-1851. [PMID: 38066674 DOI: 10.1093/jxb/erad478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 12/04/2023] [Indexed: 03/28/2024]
Abstract
Aureochromes (AUREOs) are unique blue light receptors and transcription factors found only in stramenopile algae. While each of the four AUREOs identified in the diatom Phaeodactylum tricornutum may have a specific function, PtAUREO1a has been shown to have a strong impact on overall gene regulation, when light changes from red to blue light conditions. Despite its significance, the molecular mechanism of PtAUREO1a is largely unexplored. To comprehend the overall process of gene regulation by PtAUREO1a, we conducted a series of in vitro and in vivo experiments, including pull-down assays, yeast one-hybrid experiments, and phenotypical characterization using recombinant PtAUREOs and diatom mutant lines expressing a modified PtAureo1a gene. We describe the distinct light absorption properties of four PtAUREOs and the formation of all combinations of their potential dimers. We demonstrate the capability of PtAUREO1a and 1b to activate the genes, diatom-specific cyclin 2, PtAureo1a, and PtAureo1c under both light and dark conditions. Using mutant lines expressing a modified PtAUREO1a protein with a considerably reduced light absorption, we found novel evidence that PtAUREO1a regulates the expression of PtLHCF15, which is essential for red light acclimation. Based on current knowledge, we present a working model of PtAUREO1a gene regulation properties.
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Affiliation(s)
- Soo Hyun Im
- Plant Ecophysiology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Bernard Lepetit
- Plant Ecophysiology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
- Molecular Stress Physiology, Institute of Biological Sciences, University of Rostock, D-18059 Rostock, Germany
| | - Niccolò Mosesso
- Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Sandeep Shrestha
- Plant Ecophysiology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Laura Weiss
- Plant Ecophysiology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Marianne Nymark
- Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Robert Roellig
- Institute of Biology, Department of Plant Physiology, University of Leipzig, D-04103 Leipzig, Germany
| | - Christian Wilhelm
- Institute of Biology, Department of Plant Physiology, University of Leipzig, D-04103 Leipzig, Germany
| | - Erika Isono
- Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | - Peter G Kroth
- Plant Ecophysiology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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