DREB1\/CBFs are key transcription factors involved in plant cold stress adaptation. The expression of DREB1\/CBFs triggers a cold-responsive transcriptional cascade, after which many stress tolerance genes are expressed. Thus, elucidating the mechanisms of cold stress-inducible DREB1\/CBF expression is important to understand the molecular mechanisms of plant cold stress responses and tolerance. We analyzed the roles of a transcription factor, INDUCER OF CBF EXPRESSION1 (ICE1), that is well known as an important transcriptional activator in the cold-inducible expression of DREB1A\/CBF3 in Arabidopsis (Arabidopsis thaliana). ice1-1 is a widely accepted mutant allele known to abolish cold-inducible DREB1A expression, and this evidence has strongly supported ICE1-DREB1A regulation for many years. However, in ice1-1 outcross descendants, we unexpectedly discovered that ice1-1 DREB1A repression was genetically independent of the ice1-1 allele ICE1(R236H). Moreover, neither ICE1 overexpression nor double loss-of-function mutation of ICE1 and its homolog SCRM2 altered DREB1A expression. Instead, a transgene locus harboring a reporter gene in the ice1-1 genome was responsible for altering DREB1A expression. The DREB1A promoter was hypermethylated due to the transgene. We showed that DREB1A repression in ice1-1 results from transgene-induced silencing and not genetic regulation by ICE1. The ICE1(R236H) mutation has also been reported as scrm-D, which confers constitutive stomatal differentiation. The scrm-D phenotype and the expression of a stomatal differentiation marker gene were confirmed to be linked to the ICE1(R236H) mutation. We propose that the current ICE1-DREB1 regulatory model should be revalidated without the previous assumptions.<\/p>\n","protected":false},"excerpt":{"rendered":"
Satoshi Kidokoro, June-Sik Kim, Tomona Ishikawa, Takamasa Suzuki, Kazuo Shinozaki, Kazuko Yamaguchi-Shinozaki […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"_links":{"self":[{"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/posts\/213"}],"collection":[{"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/comments?post=213"}],"version-history":[{"count":0,"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/posts\/213\/revisions"}],"wp:attachment":[{"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/media?parent=213"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/categories?post=213"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/biochemistry.isc.chubu.ac.jp\/labo\/suzuki\/wp-json\/wp\/v2\/tags?post=213"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}