Nuclear localization of sweet cherry DREB1/CBF ortholog (CIG) and low temperature-inducible activity of CIG promoter

The fluorescent signal of GFP fused to CIG-B, which is one of the three DREB1/CBF (dehydration responsive element binding protein 1/C-repeat binding factor) homologs isolated from sweet cherry, was observed only in nucleus. The expression of GFP driven by CIG-B promoter was up-regulated by low-temperature. These results suggested that nuclear localization signal (NLS) motif in the N-terminal region of CIG-B protein and inducer of CBF expression (ICE)-like motifs in CIG-B promoter could be responsible for nuclear targeting and low temperature perception, respectively.