title: Characterization of marine diatom-infecting virus promoters in the model diatom Phaeodactylum tricornutum.
abstract: Viruses are considered key players in phytoplankton population control in oceans. However, mechanisms that control viral gene expression in prominent microalgae such as diatoms remain largely unknown. In this study, potential promoter regions isolated from several marine diatom-infecting viruses (DIVs) were linked to the egfp reporter gene and transformed into the Pennales diatom Phaeodactylum tricornutum. We analysed their activity in cells grown under different conditions. Compared to diatom endogenous promoters, novel DIV promoter (ClP1) mediated a significantly higher degree of reporter transcription and translation. Stable expression levels were observed in transformants grown under both light and dark conditions, and high levels of expression were reported in cells in the stationary phase compared to the exponential phase of growth. Conserved motifs in the sequence of DIV promoters were also found. These results allow the identification of novel regulatory regions that drive DIV gene expression and further examinations of the mechanisms that control virus-mediated bloom control in diatoms. Moreover, the identified ClP1 promoter can serve as a novel tool for metabolic engineering of diatoms. This is the first report describing a promoter of DIVs that may be of use in basic and applied diatom research.
authors.affiliation: Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture, Kochi University, Otsu-200, Monobe, Nankoku, Kochi 783-8502, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kadono
authors.affiliation: Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture, Kochi University, Otsu-200, Monobe, Nankoku, Kochi 783-8502, Japan.
authors.forename: Arisa
authors.initials: A
authors.lastname: Miyagawa-Yamaguchi
authors.affiliation: The United Graduate School of Agricultural Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566 Japan.
authors.forename: Nozomu
authors.initials: N
authors.lastname: Kira
authors.affiliation: National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tomaru
authors.affiliation: Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture, Kochi University, Otsu-200, Monobe, Nankoku, Kochi 783-8502, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Okami
authors.affiliation: Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture, Kochi University, Otsu-200, Monobe, Nankoku, Kochi 783-8502, Japan.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Yoshimatsu
authors.affiliation: School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502, Japan.
authors.forename: Liyuan
authors.initials: L
authors.lastname: Hou
authors.affiliation: School of Environmental Science and Engineering, Kochi University of Technology, Tosayamada, Kami, Kochi 782-8502, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohama
authors.affiliation: Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture, Kochi University, Otsu-200, Monobe, Nankoku, Kochi 783-8502, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Fukunaga
authors.affiliation: National Research Institute of Aquaculture, Fisheries Research Agency, 422-1 Nakatsuhamaura, Minami-ise, Mie 516-0193, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Okauchi
authors.affiliation: Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture, Kochi University, Otsu-200, Monobe, Nankoku, Kochi 783-8502, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Research Institute of Molecular Genetics, Kochi University, Otsu-200, Nankoku, Kochi 783-8502, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Ohnishi
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine, UMR 7238, F-75006 Paris, France; CNRS, UMR 7238, F-75006 Paris, France.
authors.forename: Angela
authors.initials: A
authors.lastname: Falciatore
authors.affiliation: Laboratory of Aquatic Environmental Science (LAQUES), Faculty of Agriculture, Kochi University, Otsu-200, Monobe, Nankoku, Kochi 783-8502, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Adachi
mesh_terms: D003198:Computer Simulation; D004247:DNA / Q000302:isolation & purification; D017377:Diatoms / Q000821:virology*; D005434:Flow Cytometry; D005453:Fluorescence; D005796:Genes; D049452:Green Fluorescent Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D012623:Seawater; D014170:Transformation, Genetic; D014780:Viruses / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D004247:DNA