title: The putative Agrobacterium transcriptional activator-like virulence protein VirD5 may target T-complex to prevent the degradation of coat proteins in the plant cell nucleus.
abstract: Agrobacterium exports at least five virulence proteins (VirE2, VirE3, VirF, VirD2, VirD5) into host cells and hijacks some host plant factors to facilitate its transformation process. Random DNA binding selection assays (RDSAs), electrophoretic mobility shift assays (EMSAs) and yeast one-hybrid systems were used to identify protein-bound DNA elements. Bimolecular fluorescence complementation, glutathione S-transferase pull-down and yeast two-hybrid assays were used to detect protein interactions. Protoplast transformation, coprecipitation, competitive binding and cell-free degradation assays were used to analyze the relationships among proteins. We found that Agrobacterium VirD5 exhibits transcriptional activation activity in yeast, is located in the plant cell nucleus, and forms homodimers. A specific VirD5-bound DNA element designated D5RE (VirD5 response element) was identified. VirD5 interacted directly with Arabidopsis VirE2 Interacting Protein 1 (AtVIP1). However, the ternary complex of VirD5-AtVIP1-VirE2 could be detected, whereas that of VirD5-AtVIP1-VBF (AtVIP1 Binding F-box protein) could not. We demonstrated that VirD5 competes with VBF for binding to AtVIP1 and stabilizes AtVIP1 and VirE2 in the cell-free degradation system. Our results indicated that VirD5 may act as both a transcriptional activator-like effector to regulate host gene expression and a protector preventing the coat proteins of the T-complex from being quickly degraded by the host's ubiquitin proteasome system (UPS).
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Peng
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhou
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Huang
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Lingyun
authors.initials: L
authors.lastname: Shao
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Meizhong
authors.initials: M
authors.lastname: Luo
mesh_terms: D060054:Agrobacterium / Q000378:metabolism / Q000472:pathogenicity*; D029681:Arabidopsis Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001667:Binding, Competitive; D002467:Cell Nucleus / Q000378:metabolism*; D002474:Cell-Free System; D004269:DNA, Bacterial / Q000378:metabolism*; D012275:Oryza; D059828:Plant Cells / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D055550:Protein Stability; D021381:Protein Transport; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013347:Subcellular Fractions / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D037521:Virulence Factors / Q000378:metabolism*; D028901:alpha Karyopherins / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C036483:T-DNA; D015534:Trans-Activators; C432104:VIP1 protein, Arabidopsis; D037521:Virulence Factors; D028901:alpha Karyopherins
keywords: Agrobacterium; AtVIP1; T-complex; VBF; VirD5; VirE2; coat proteins; transcriptional activator-like virulence protein