Rai R, Genbauffe F S, Sumrada R A, Cooper T G
Department of Microbiology and Immunology, University of Tennessee, Memphis 38163.
Mol Cell Biol. 1989 Feb;9(2):602-8. doi: 10.1128/mcb.9.2.602-608.1989.
DAL5 is a constitutively expressed allantoin system gene whose product is required for allantoate transport. Its simple pattern of expression prompted us to use this gene for identifying the element(s) that mediates transcriptional activation of allantoin system genes. Deletion analysis of the DAL5 5'-flanking sequences resulted in identification of two small regions required for DAL5 expression. Analysis of these two regions with synthetic oligonucleotides localized the sequences supporting transcriptional activation to two DNA fragments of 10 to 12 base pairs, each containing one copy of the pentanucleotide 5'-GATAA-3'. The 5'-flanking region of DAL5 contained eight copies of this sequence. Synthetic constructions containing single copies of these fragments were unable to support transcriptional activation, while those containing two or more copies supported high-level activation. The 5'-GATAA-3' sequence was also found beneath the footprint of a DNA-binding protein. These observations are consistent with the suggestion that DNA fragments containing the sequence 5'-GATAA-3' play an important role in DAL5 gene expression, probably representing a portion of the binding site for a transcriptional activation factor.
DAL5是一个组成型表达的尿囊素系统基因，其产物是尿囊酸转运所必需的。其简单的表达模式促使我们利用该基因来鉴定介导尿囊素系统基因转录激活的元件。对DAL5 5'侧翼序列的缺失分析导致鉴定出DAL5表达所需的两个小区域。用合成寡核苷酸对这两个区域进行分析，将支持转录激活的序列定位到两个10至12个碱基对的DNA片段上，每个片段含有一个五核苷酸5'-GATAA-3'拷贝。DAL5的5'侧翼区域含有该序列的八个拷贝。含有这些片段单拷贝的合成构建体无法支持转录激活，而含有两个或更多拷贝的构建体则支持高水平激活。在一种DNA结合蛋白的足迹下也发现了5'-GATAA-3'序列。这些观察结果与以下观点一致，即含有5'-GATAA-3'序列的DNA片段在DAL5基因表达中起重要作用，可能代表转录激活因子结合位点的一部分。
