DNA-SEQUENCE REQUIREMENTS FOR TRANSCRIPTIONAL INITIATOR ACTIVITY IN MAMMALIAN-CELLS
DNA-SEQUENCE REQUIREMENTS FOR TRANSCRIPTIONAL INITIATOR ACTIVITY IN MAMMALIAN-CELLS
复制标题
DOI：
10.1128/mcb.14.1.116
复制
发表时间：
1994-01-01
影响因子：
5.3
通讯作者：
SMALE, ST
中科院分区：
文献类型：
--
作者：
JAVAHERY, R;KHACHI, A;SMALE, ST
哺乳动物RNA聚合酶II的转录起始子（Inr）可以定义为与转录起始位点重叠并且足以（i）确定缺乏TATA盒的启动子中的起始位点位置和（ii）增强含有TATA盒的启动子的强度的DNA序列元件。我们制备了包含Sp1结合位点下游随机核苷酸的合成启动子，以确定传递Inr活性的DNA序列范围。许多序列在体外转录试验中表现为功能性Inr，但Inr活性变化很大。对功能元件的检查揭示了松散但一致的序列要求，具有近似的共有序列Py Py A+1 N T/A Py Py。最重要的是，几乎所有已经描述的功能性Inr都符合我们定义的共有序列。虽然已经报道了几种蛋白质与特异性Inr结合，但对这些元件的操作未能将蛋白质结合与Inr活性相关联。解释这些结果的最简单模型是，所有或大多数Inr被通用结合蛋白识别，类似于相同TATA结合蛋白对所有TATA序列的功能识别。以前报道的蛋白质，结合附近的特定Inr元素可能会增加强度的Inr或可能会通过Inr赋予转录调控。
A transcriptional initiator (Inr) for mammalian RNA polymerase II can be defined as a DNA sequence element that overlaps a transcription start site and is sufficient for (i) determining the start site location in a promoter that lacks a TATA box and (ii) enhancing the strength of a promoter that contains a TATA box. We have prepared synthetic promoters containing random nucleotides downstream of Sp1 binding sites to determine the range of DNA sequences that convey Inr activity. Numerous sequences behaved as functional Inrs in an in vitro transcription assay, but the Inr activities varied dramatically. An examination of the functional elements revealed loose but consistent sequence requirements, with the approximate consensus sequence Py Py A+1 N T/A Py Py. Most importantly, almost every functional Inr that has been described fits into the consensus sequence that we have defined. Although several proteins have been reported to bind to specific Inrs, manipulation of those elements failed to correlate protein binding with Inr activity. The simplest model to explain these results is that all or most Inrs are recognized by a universal binding protein, similar to the functional recognition of all TATA sequences by the same TATA-binding protein. The previously reported proteins that bind near specific Inr elements may augment the strength of an Inr or may impart transcriptional regulation through an Inr.