Abstract
We have identified a High-Light inducible NAC transcription factor (HLN) in Arabidopsis. The plant-specific NAC transcription factors consist of an N-terminal conserved NAC-domain required for DNA binding and a C-terminal activation domain. Interestingly, HLN also contained a transmembrane motif (TM) in the C-terminal region. Moreover, the expression of HLN-target genes was not up-regulated under normal conditions in the HLN-overexpressing Arabidopsis, suggesting that HLN might be expressed as a membraneassociated, dormant form, and then translocated to nucleus to activate its target genes under stressful conditions. Therefore, we investigated the subcellular localization of GFP fused full-length HLN and truncated form of HLN without TM motif (HLNΔTM). GFP-HLN was localized in the cytosol. In contrast, GFP-HLNΔTM was localized in the nucleus. These finding suggest that HLN is translocated to nucleus by the release from the membrane under stressful conditions and then functions as a transcriptional activator.
