Qureshi Sohail A
Department of Biological and Biomedical Sciences, The Aga Khan University Hospital, Karachi, Pakistan.
Can J Microbiol. 2006 Nov;52(11):1136-40. doi: 10.1139/w06-073.
Archaeal promoters contain a TATA-box, an adjacent upstream TFB-recognition element (BRE), and a downstream initiator (INR) region from which transcription originates. While the contribution of A-box and BRE to promoter strength is well established, the role of DNA sequences within the INR region and its vicinity on transcription efficiency and start site selection remains unclear. Here, I demonstrate using the strong Sulfolobus shibatae viral T6 promoter that either substitution of its natural sequence from -17 and beyond with plasmid DNA or introduction of point transversion mutations at +3, -2, -4, and -5 positions reduce promoter strength dramatically, whereas +1, -1, and -2 mutations influence the transcription start site. These data therefore reveal that the INR region plays a role as important as the BRE and the A-box in T6 gene transcription.
古菌启动子包含一个TATA框、一个相邻的上游TFB识别元件（BRE）以及一个下游起始子（INR）区域，转录从此区域起始。虽然A框和BRE对启动子强度的贡献已得到充分证实，但INR区域及其附近的DNA序列对转录效率和起始位点选择的作用仍不清楚。在这里，我使用强大的嗜热栖热硫化叶菌病毒T6启动子证明，用质粒DNA替换其从-17及更下游的天然序列，或在+3、-2、-4和-5位置引入点颠换突变，会显著降低启动子强度，而+1、-1和-2突变会影响转录起始位点。因此，这些数据表明INR区域在T6基因转录中发挥着与BRE和A框同样重要的作用。
