title: A R2R3 type MYB transcription factor is involved in the cold regulation of CBF genes and in acquired freezing tolerance.
abstract: Cold temperatures trigger the expression of the CBF family of transcription factors, which in turn activate many downstream genes that confer freezing tolerance to plants. It has been shown previously that the cold regulation of CBF3 involves an upstream bHLH-type transcription factor, ICE1. ICE1 binds to the Myc recognition sequences in the CBF3 promoter. Apart from Myc recognition sequences, CBF promoters also have Myb recognition sequences. We report here that the Arabidopsis MYB15 is involved in cold-regulation of CBF genes and in the development of freezing tolerance. The MYB15 gene transcript is up-regulated by cold stress. The MYB15 protein interacts with ICE1 and binds to Myb recognition sequences in the promoters of CBF genes. Overexpression of MYB15 results in reduced expression of CBF genes whereas its loss-of-function leads to increased expression of CBF genes in the cold. The myb15 mutant plants show increased tolerance to freezing stress whereas its overexpression reduces freezing tolerance. Our results suggest that MYB15 is part of a complex network of transcription factors controlling the expression of CBFs and other genes in response to cold stress.
authors.affiliation: Institute for Integrative Genome Biology and Department of Botany & Plant Science, University of California, Riverside, California 92521, USA.
authors.forename: Manu
authors.initials: M
authors.lastname: Agarwal
authors.forename: Yujin
authors.initials: Y
authors.lastname: Hao
authors.forename: Avnish
authors.initials: A
authors.lastname: Kapoor
authors.forename: Chun-Hai
authors.initials: CH
authors.lastname: Dong
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Fujii
authors.forename: Xianwu
authors.initials: X
authors.lastname: Zheng
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
mesh_terms: D000064:Acclimatization / Q000235:genetics / Q000502:physiology; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000502:physiology*; D001483:Base Sequence; D003081:Cold Climate; D018744:DNA, Plant / Q000235:genetics; D005615:Freezing; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D009154:Mutation; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; C114578:DREB1A protein, Arabidopsis; C510502:ICE1 protein, Arabidopsis; C500589:Myb protein, Arabidopsis; D014157:Transcription Factors