Induction and repression of DAN1 and the family of anaerobic mannoprotein genes in Saccharomyces cerevisiae occurs through a complex array of regulatory sites
Induction and repression of DAN1 and the family of anaerobic mannoprotein genes in Saccharomyces cerevisiae occurs through a complex array of regulatory sites
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DOI：
10.1093/nar/29.3.799
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发表时间：
2001-02-01
影响因子：
14.9
通讯作者：
Lowry, CV
中科院分区：
文献类型：
--
作者：
Cohen, BD;Sertil, O;Lowry, CV
酿酒酵母的DAN/TIR甘露蛋白基因（DAN1、DAN2、DAN3、DAN4、TIR1、TIR2、TIR3和TIR4）在厌氧细胞中表达，而优势细胞壁蛋白Cwp1和Cwp2则下调。本研究以DAN1启动子为模型，定义了参与DAN/TIR基因激活和抑制的元件。DAN1/lacZ报告器中的嵌套缺失精确定位了携带激活和抑制元素的区域。经检验发现两个一致序列为独立的厌氧反应元件（AR2, consensus TCGTTYAG; AR2, consensus AAAAATTGTTGA）。AR1存在于所有的DAN/TIR启动子中；AR2存在于DAN1、DAN2和DAN3中。一个120 bp的片段携带两个AR1拷贝，在厌氧条件下优先激活lacZ的转录。AR1的三个合成拷贝与MEL1的融合也以厌氧方式表达。120bp片段中AR1位点的突变导致了表达的急剧缺失，这表明两者都是激活所必需的，并且暗示了相邻转录激活复合物之间的协同作用。在厌氧条件下，单个AR2位点携带的来自DAN1启动子的46 bp片段激活了lacZ转录，与MEL1融合的26 bp合成AR2片段也激活了lacZ转录。AR2序列内的核苷酸替换消除了46 bp片段的活性。全启动子中AR2序列的消融导致部分表达减少。在AR2序列中存在ATTGTT核心（HMG蛋白识别）表明HMG蛋白可能通过AR2激活，其中一个区域与DAN1的有氧抑制有关，它包含血红素诱导的Mot3和Rox1抑制因子的位点。
The DAN/TIR mannoprotein genes of Saccharomyces cerevisiae (DAN1, DAN2, DAN3, DAN4, TIR1, TIR2, TIR3 and TIR4) are expressed in anaerobic cells while the predominant cell wall proteins Cwp1 and Cwp2 are down-regulated. Elements involved in activation and repression of the DAN/TIR genes were defined in this study, using the DAN1 promoter as a model. Nested deletions in a DAN1/lacZ reporter pinpointed regions carrying activation and repression elements. Inspection revealed two consensus sequences subsequently shown to be independent anaerobic response elements (AR2, consensus TCGTTYAG; AR2, consensus AAAAATTGTTGA). AR1 is found in all of the DAN/TIR promoters; AR2 is found in DAN1, DAN2 and DAN3. A 120 bp segment carrying two copies of AR1 preferentially activated transcription of lacZ under anaerobic conditions. A fusion of three synthetic copies of AR1 to MEL1 was also expressed anaerobically. Mutations in either AR1 site within the 120 bp segment caused a drastic loss of expression, indicating that both are necessary for activation and implying cooperativity between adjacent transcriptional activation complexes. A single AR2 site carried on a 46 bp fragment from the DAN1 promoter activated lacZ transcription under anaerobic conditions, as did a 26 bp synthetic AR2 fragment fused to MEL1. Nucleotide substitutions within the AR2 sequence eliminated the activity of the 46 bp segment. Ablation of the AR2 sequences in the full promoter caused a partial reduction of expression. The presence of the ATTGTT core (recognized by HMG proteins) in the AR2 sequence suggests that an HMG protein may activate through AR2, One region was implicated in aerobic repression of DAN1, It contains sites for the heme-induced Mot3 and Rox1 repressors.