Tobacco ZFT1, a transcriptional repressor with a Cys2/His2 type zinc finger motif that functions in spermine-signaling pathway.
We previously proposed that a spermine (Spm)-mediated signal transduction pathway is involved in the hypersensitive response induced by Tobacco mosaic virus (TMV) in tobacco plants. To identify regulatory component(s) of this pathway, we surveyed a tobacco cDNA library and found that the ZFT1 gene, which encodes a Cys2/His2 type zinc-finger protein, is Spm-responsive. ZFT1 was not induced by two other polyamines, putrescine and spermidine, or by salicylic acid (SA), jasmonic acid or ethylene. Furthermore, ZFT1 was upregulated in TMV- inoculated tobacco plants in an N gene-dependent manner. Notably, induction of ZFT1 by Spm and by TMV infection was unimpaired in NahG-transgenic tobacco plants, indicating that cross-talk with an SA signaling pathway is not involved in this response. Within the Spm-signaling pathway, we found that ZFT1 functioned downstream of both mitochondrial dysfunction and mitogen-activated protein kinase activation. The ZFT1 protein has two zinc finger motifs and shows a high degree of similarity to ZPT2-3 in petunia and SCOF1 in soybean. However, unlike the latter two proteins, ZFT1 binds to the EP1S sequence and functions as a transcription repressor. Moreover, interestingly, ZFT1 overexpression rendered tobacco plants more tolerant to TMV. Based on the results presented here, we propose that ZFT1 functions as a transcription repressor in a Spm signaling pathway, thereby accelerating necrotic local region formation in tobacco leaves.
Uehara
Yukiko
Y
Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, 980-8577, Aoba, Sendai, Miyagi, Japan.
Takahashi
Yoshihiro
Y
Berberich
Thomas
T
Miyazaki
Atsushi
A
Takahashi
Hideki
H
Matsui
Kyoko
K
Ohme-Takagi
Masaru
M
Saitoh
Hiromasa
H
Terauchi
Ryohei
R
Kusano
Tomonobu
T
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D034822:Commelina / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D030821:Plants, Genetically Modified; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics* / Q000502:physiology; D013096:Spermine / Q000494:pharmacology*; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology; D014027:Tobacco Mosaic Virus / Q000254:growth & development; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D016335:Zinc Fingers / Q000235:genetics*
D015345:Oligonucleotide Probes; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D013096:Spermine; D008156:Luciferases