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Fig. 2. LEA-type gene transcription under abiotic stresses in Arabidopsis. ABA-independent DREB2 and ABA-dependent CBF4 transcription factors transactivate DRE/CRT cis-elements in the promoters of LEA type genes. ABA-dependent pathways regulate LEA type genes through MYC/MYB and bZIP type transcription factors. ABA-dependent signaling is mediated through IP3 and Ca2+. FRY1 negatively regulates IP3 levels. ABA induced Ca2+ signaling is negatively regulated by ABI1/2 protein phosphatase 2C. Low temperature stress activates ICE1 a myc-like bHLH transcription factor, which binds to myc type cis-elements of CBF3 promoter and induces CBF3 expression. CBFs bind to the CRT/DRE cis-elements on the promoter of LEA-type genes and induce expression of these genes.
