title: Oleosome-associated protein of the oleaginous diatom Fistulifera solaris contains an endoplasmic reticulum-targeting signal sequence.
abstract: Microalgae tend to accumulate lipids as an energy storage material in the specific organelle, oleosomes. Current studies have demonstrated that lipids derived from microalgal oleosomes are a promising source of biofuels, while the oleosome formation mechanism has not been fully elucidated. Oleosome-associated proteins have been identified from several microalgae to elucidate the fundamental mechanisms of oleosome formation, although understanding their functions is still in infancy. Recently, we discovered a diatom-oleosome-associated-protein 1 (DOAP1) from the oleaginous diatom, Fistulifera solaris JPCC DA0580. The DOAP1 sequence implied that this protein might be transported into the endoplasmic reticulum (ER) due to the signal sequence. To ensure this, we fused the signal sequence to green fluorescence protein. The fusion protein distributed around the chloroplast as like a meshwork membrane structure, indicating the ER localization. This result suggests that DOAP1 could firstly localize at the ER, then move to the oleosomes. This study also demonstrated that the DOAP1 signal sequence allowed recombinant proteins to be specifically expressed in the ER of the oleaginous diatom. It would be a useful technique for engineering the lipid synthesis pathways existing in the ER, and finally controlling the biofuel quality.
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan. y_maeda@cc.tuat.ac.jp.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan. okihihsoy1985@gmail.com.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sunaga
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan. y-tomoko@cc.tuat.ac.jp.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Yoshino
authors.affiliation: Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan. tsuyo@cc.tuat.ac.jp.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D056804:Biofuels; D017377:Diatoms / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D050356:Lipid Metabolism; D058086:Microalgae / Q000648:ultrastructure*; D015388:Organelles / Q000737:chemistry*; D021382:Protein Sorting Signals; D011506:Proteins / Q000737:chemistry*
chemical_list: D056804:Biofuels; D021382:Protein Sorting Signals; D011506:Proteins; D049452:Green Fluorescent Proteins