75.プロテアゾームを介したリプレッサー型エチレン応答性転写因子の機能制御の解析(口頭発表)

概要

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Plants respond to environmental stimuli by regulating expression of various genes. The coordinated expression of the genes is achieved by the action of transcriptional activators and repressors. NtERF3 acts as a repressor and the repressive activity is mediated by the ERF-associated amphiphilic repression (EAR) motif. Since NtERF3 can repress expression of the target genes in the presence of ERF activators, NtERF3 is a pivotal for expression of the target genes. We have demonstrated that NtERF3 interacts with NtUBC2, a ubiquitin-conjugating enzyme, and NtERF3 is regulated by NtUBC2. In this work, we first examined the stability of the recombinant NtERF3 in an extract prepared from tobacco cells and found that the recombinant NtERF3 was degraded rapidly. Next, we found that NtERF3 (83/190) was essential and sufficient for the instability in vitro. The consistent results were obtained from the comparative analysis of the level of individual GFPs fused with various regions of NtERF3 in Arabidopsis plants. To assess the involvement of proteasome in the stability of NtERF3, we subjected GFP-NtERF3 plants to MG132, a proteasome inhibitor, and found that GFP-ERF3 was increased by MG132. Moreover, we found autonomous cell death in the plants expressing GFP-ERF3(Δ83-190), a stable version of NtERF3. Taken together, we propose that the NtERF3 is a positive regulator for the induction of cell death and its activity is fine tuned by proteasome.
2010-10-01