Stockinger E J, Mao Y, Regier M K, Triezenberg S J, Thomashow M F
Department of Crop and Soil Sciences and Department of Biochemistry, Michigan State University, East Lansing, MI 48824, USA.
Nucleic Acids Res. 2001 Apr 1;29(7):1524-33. doi: 10.1093/nar/29.7.1524.
The ARABIDOPSIS CBF transcriptional activators bind to the CRT/DRE regulatory element present in the promoters of many cold-regulated genes and stimulate their transcription. Expression of the CBF1 proteins in yeast activates reporter genes carrying a minimal promoter with the CRT/DRE as an upstream regulatory element. Here we report that this ability of CBF1 is dependent upon the activities of three key components of the yeast Ada and SAGA complexes, namely the histone acetyltransferase (HAT) Gcn5 and the transcriptional adaptor proteins Ada2 and Ada3. This result suggested that CBF1 might function through the action of similar complexes in ARABIDOPSIS In support of this hypothesis we found that ARABIDOPSIS has a homolog of the GCN5 gene and two homologs of ADA2, the first report of multiple ADA2 genes in an organism. The ARABIDOPSIS GCN5 protein has intrinsic HAT activity and can physically interact in vitro with both the ARABIDOPSIS ADA2a and ADA2b proteins. In addition, the CBF1 transcriptional activator can interact with the ARABIDOPSIS GCN5 and ADA2 proteins. We conclude that ARABIDOPSIS encodes HAT-containing adaptor complexes that are related to the Ada and SAGA complexes of yeast and propose that the CBF1 transcriptional activator functions through the action of one or more of these complexes.
拟南芥CBF转录激活因子与许多冷调控基因启动子中存在的CRT/DRE调控元件结合，并刺激它们的转录。CBF1蛋白在酵母中的表达可激活携带以CRT/DRE作为上游调控元件的最小启动子的报告基因。在此我们报道，CBF1的这种能力依赖于酵母Ada和SAGA复合物的三个关键组分的活性，即组蛋白乙酰转移酶（HAT）Gcn5以及转录衔接蛋白Ada2和Ada3。这一结果表明，CBF1可能通过拟南芥中类似复合物的作用发挥功能。为支持这一假设，我们发现拟南芥有一个GCN5基因的同源物和两个ADA2的同源物，这是在一个生物体中首次报道存在多个ADA2基因。拟南芥GCN5蛋白具有内在的HAT活性，并且在体外能与拟南芥ADA2a和ADA2b蛋白发生物理相互作用。此外，CBF1转录激活因子能与拟南芥GCN5和ADA2蛋白相互作用。我们得出结论，拟南芥编码与酵母的Ada和SAGA复合物相关的含HAT的衔接复合物，并提出CBF1转录激活因子通过这些复合物中的一种或多种的作用发挥功能。
