title: Secretion of immunodominant membrane protein from onion yellows phytoplasma through the Sec protein-translocation system in Escherichia coli.
abstract: A gene that encodes a putative SecE protein, which is a component of the Sec protein-translocation system, was cloned from the onion yellows phytoplasma (OY). The identification of this gene and the previously reported genes encoding SecA and SecY provides evidence that the Sec system exists in phytoplasma. In addition, a gene encoding an antigenic membrane protein (Amp) (a type of immunodominant membrane protein) of OY was cloned and sequenced. The OY amp gene consisted of 702 nt encoding a protein of 233 aa which was highly similar to Amp of aster yellows phytoplasma (AY). Part of OY Amp was overexpressed in Escherichia coli, purified, and used to raise an anti-Amp polyclonal antibody. The anti-Amp antibody reacted specifically with an OY-infected plant extract in Western blot analysis and was therefore useful for the detection of OY as well as Amp. Amp has a conserved protein motif that is known to be exported by the Sec system of E. coli. A partial OY Amp protein expressed in E. coli was localized in the periplasm as a shorter, putatively processed form of the protein. It had probably been exported from the cytoplasm to the periplasm through the Sec system. Moreover, OY Amp protein expressed in OY and detected in OY-infected plants was apparently also processed. Because phytoplasmas cannot be cultured or transformed, little information is available regarding their protein secretion systems. This study suggests that the Sec system operates in this phytoplasma to export OY Amp.
authors.affiliation: Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kakizawa
authors.affiliation: Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Kenro
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Nishigawa
authors.affiliation: Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Hee-Young
authors.initials: HY
authors.lastname: Jung
authors.affiliation: Division of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: National Agricultural Research Center, National Agricultural Research Organization, 3-1-1 Kannondai, Tsukuba-shi, Ibaraki 305-8666, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Miyata
authors.affiliation: Division of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.|Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Ugaki
authors.affiliation: Division of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.|Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
authors.forename: Shigetou
authors.initials: S
authors.lastname: Namba
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005798:Genes, Bacterial; D016056:Immunodominant Epitopes / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D045582:Phytoplasma / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000069816:SEC Translocation Channels; D000081416:SecA Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D016056:Immunodominant Epitopes; D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; D000069816:SEC Translocation Channels; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins