Paietta John V
Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH 45435, USA.
Fungal Genet Biol. 2008 Aug;45(8):1166-71. doi: 10.1016/j.fgb.2008.05.001. Epub 2008 May 16.
The CYS3 transcription factor is a basic region-leucine zipper (bZIP) DNA-binding protein that is essential for the expression of a coordinately regulated group of genes involved in the acquisition and utilization of sulfur in Neurospora crassa. An approach of using binding-site selection from random-sequence oligonucleotides was used to define CYS3-binding specificity. The derived consensus-binding site of ATGGCGCCAT defines a symmetrical sequence (half-site A T G/t G/a C/t) that resembles that of other bZIP proteins such as CREB and C/EBP. By comparison, CYS3 shows a greater range of binding to a central core of varied Pur-Pyr-Pur-Pyr sequences than CREB as determined by gel shift assays. The derived CYS3 consensus binding sequence was further validated by demonstrating in vivo sulfur regulation using a heterologous promoter construct. The CYS3-binding site data will be useful for the genome-wide study of sulfur-regulated genes in N. crassa, which has served as a model fungal sulfur control system.
CYS3转录因子是一种碱性区域-亮氨酸拉链（bZIP）DNA结合蛋白，对于粗糙脉孢菌中一组参与硫获取和利用的协同调控基因的表达至关重要。采用从随机序列寡核苷酸中进行结合位点选择的方法来确定CYS3的结合特异性。推导得出的CYS3共有结合位点ATGGCGCCAT定义了一个对称序列（半位点A T G/t G/a C/t），该序列与其他bZIP蛋白如CREB和C/EBP的序列相似。相比之下，通过凝胶迁移实验测定，CYS3与不同嘌呤-嘧啶-嘌呤-嘧啶序列的中央核心的结合范围比CREB更大。通过使用异源启动子构建体证明体内硫调控，进一步验证了推导得出的CYS3共有结合序列。CYS3结合位点数据将有助于在粗糙脉孢菌中进行全基因组硫调控基因研究，粗糙脉孢菌已作为一种典型的真菌硫控制系统。
