Secretion of immunodominant membrane protein from onion yellows phytoplasma through the Sec protein-translocation system in Escherichia coli.
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.
Kakizawa
Shigeyuki
S
Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
Oshima
Kenro
K
Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
Nishigawa
Hisashi
H
Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
Jung
Hee-Young
HY
Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
Wei
Wei
W
Division of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Suzuki
Shiho
S
Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
Tanaka
Minoru
M
National Agricultural Research Center, National Agricultural Research Organization, 3-1-1 Kannondai, Tsukuba-shi, Ibaraki 305-8666, Japan.
Miyata
Shin-Ichi
SI
Division of Integrated Biosciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Chiba 277-8562, Japan.
Ugaki
Masashi
M
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.
Namba
Shigetou
S
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.
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
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