DREB1A/CBF3 Is Repressed by Transgene-Induced DNA Methylation in the Arabidopsis ice1 -1 Mutant.
Plant Cell
; 32(4): 1035-1048, 2020 04.
Article
em En
| MEDLINE
| ID: mdl-32034036
ABSTRACT
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
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Fatores de Transcrição
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Arabidopsis
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Transgenes
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Metilação de DNA
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Proteínas de Arabidopsis
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Mutação
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article