Abstract
COP9 signalosome (CSN) is a nuclear complex regulating signal transduction in plants and animals. To dissect the function of CSN, we focus on the function of CSN1 subunit. The N-terminal region of CSN1 (CSN1N) possessed a transcriptional repression activity in mammals, and was essential for survival in plants. To understand this mechanism, Yeast Two-Hybrid method was utilized to isolate proteins interacting with CSN1N in Arabidopsis. Here, we isolated a transcription factor containing a predicted structural domain composed of three helixes and two loops, a conserved signature domain of the Trihelix protein family in Arabidopsis. Through a series of pull-down assays, this transcription factor was shown to directly bind CSN1N in a specific manner. Here, we report the gene expression pattern of this transcription factor and the phenotype of its mutants. We will further characterize this transcriptional factor, and discuss its role in CSN mediated signal regulation.
