title: Activation of a novel transcription factor through phosphorylation by WIPK, a wound-induced mitogen-activated protein kinase in tobacco plants.
abstract: Wound-induced protein kinase (WIPK) is a tobacco (Nicotiana tabacum) mitogen-activated protein kinase known to play an essential role in defense against wounding and pathogens, although its downstream targets have yet to be clarified. This study identified a gene encoding a protein of 648 amino acids, which directly interacts with WIPK, designated as N. tabacum WIPK-interacting factor (NtWIF). The N-terminal region with approximately 250 amino acids showed a high similarity to the plant-specific DNA binding domain, B3, but no other similarity with known proteins. The C terminus of approximately 200 amino acids appeared to be essential for the interaction with WIPK, and a Luciferase-reporter gene assay using Bright Yellow 2 cells indicated the full-length protein to possess trans-activation activity, located to the middle region of approximately 200 amino acids. In vitro phosphorylation assays indicated that WIPK efficiently phosphorylates the full-length protein and the N terminus but not the C terminus. When full-length NtWIF was coexpressed with WIPK in Bright Yellow 2 cells, the Luciferase transcriptional activity increased up to 5-fold that of NtWIF alone, whereas no effect was observed with a kinase-deficient WIPK mutant. Transcripts of NtWIF began to simultaneously accumulate with those of WIPK 30 min after wounding and 1 h after the onset of hypersensitive response upon tobacco mosaic virus infection. These results suggest that NtWIF is a transcription factor that is directly phosphorylated by WIPK, thereby being activated for transcription of target gene(s) involved in wound and pathogen responses.
authors.affiliation: Research and Education Center for Genetic Information, Nara Institute of Science and Technology, Japan.
authors.forename: Yun-Kiam
authors.initials: YK
authors.lastname: Yap
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kodama
authors.forename: Frank
authors.initials: F
authors.lastname: Waller
authors.forename: Kwi Mi
authors.initials: KM
authors.lastname: Chung
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Ueda
authors.forename: Kimiyo
authors.initials: K
authors.lastname: Nakamura
authors.forename: Maren
authors.initials: M
authors.lastname: Oldsen
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoda
authors.forename: Yube
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sano
mesh_terms: D000595:Amino Acid Sequence; D018506:Gene Expression Regulation, Plant; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010802:Phylogeny; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D012441:Saccharomyces cerevisiae; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D020928:Mitogen-Activated Protein Kinases; C113423:WIPK protein, Nicotiana tabacum