Poster: Transcription Regulation

Abs # 1034: A novel system for gene silencing by a dominant chimeric repressor

Presenter:	Matsui, Kyoko , k-matsui@aist.go.jp
Authors	Matsui, Kyoko  (A)   Hiratsu, Keiichiro  (A)   Koyama, Tomotsugu  (A)   Tanaka, Hideo  (B)   Ohme-Takagi, Masaru  (A)
Affiliations:	(A): Gene Function Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST) (B): Institute of Applied Biochemistry, University of Tsukuba

We have developed a novel system for gene silencing using a dominant chimeric repressor that is converted from a transcriptional activator by fusion with EAR (ERF-associated amphiphilic repression) motif repression domain. Plant genes are frequently duplicated and many plant transcription factors form large families. This structural and functional redundancy of plant transcription factors often interferes with efforts to identify the functions of these factors, even when gene-knockout or antisense lines specific for a particular transcription factor can be isolated. We show here that transcription factors fused to the EAR motif, a repression domain of only 12 amino acids, act as dominant repressors in transgenic Arabidopsis and suppress the expression of specific target genes, even in the presence of the redundant transcription factors, with resultant dominant loss-of-function phenotypes. Chimeric EIN3, CUC1, PAP1 and AtMYB23 repressors that included the EAR motif dominantly suppressed the expression of their target genes and caused insensitivity to ethylene, cup-shaped cotyledons, reduction in the accumulation of anthocyanin, and absence of trichomes, respectively. This chimeric repressor silencing technology (CRES-T), exploiting the EAR-motif repression domain, is simple and effective and can overcome genetic redundancy. Thus, it should be useful not only for the rapid analysis of the functions of redundant plant transcription factors but also for the manipulation of plant traits via the suppression of gene expression that is regulated by specific transcription factors. The pleiotropic functions of AtMYB23 identified using the chimeric AtMYB23 repressor will be presented.