Abstract
In higher plants, the shoot apical meristem generates most of aerial parts. In Arabidopsis, the NAC transcription factors CUP-SHAPED COTYLEDON1 (CUC1), CUC2 and CUC3 play important roles in the formation of the shoot apical meristem and shoot organ boundaries. We have previously selected 24 candidate downstream genes of CUC by a microarray-based screening. Here we further characterized these candidates by using transgenic plants expressing a fusion protein of CUC1 and the glucocorticoid receptor (CUC1-GR). Three hours of dexamethasone (DEX) treatment, which activated CUC1 function, resulted in upregulation of three genes among the 24 candidates. Furthermore, simultaneous application of DEX and the protein synthesis inhibitor cycloheximide resulted in the upregulation of ten candidates including the above three genes, suggesting that these ten genes were direct targets of transcriptional regulation by CUC1. Now we are trying to identify target regulatory sequences of CUC1 in candidate gene promoters by using transient assays.
