McKeon C, Schmidt A, de Crombrugghe B
J Biol Chem. 1984 May 25;259(10):6636-40.
We have examined the S1 nuclease sensitivity in the promoter of both the chicken and mouse alpha 2(I) collagen genes. When these DNAs are introduced into supercoiled plasmids and digested with S1 nuclease, a discrete region containing one or more cleavages is found in each promoter. These S1 cleavage sites were mapped by the distance of the S1 site from known restriction enzyme cleavage sites. In the chicken gene, the S1-sensitive segment is located 180 to 200 base pairs preceding the start site of transcription, whereas in the mouse promoter it is between -145 to -165 base pairs. This site in the chicken promoter maps to the segment that has previously been shown to be S1 and DNase I hypersensitive in chromatin. Although these S1 sites are found at different distances from the start site of transcription in the two promoters, the sequences at these sites are strongly conserved between the two species. Each sequence consists of an identical tandem repeat containing a short palindrome within each repeat. Since the DNA sequence does not exhibit the features that would favor either a left-handed Z-DNA configuration or a cruciform structure, an alternative model is discussed that could account for the S1 sensitivity of these sequences. The conservation of these sequences and their S1 sensitivity suggests they play a role in the activation or regulation of the alpha 2(I) collagen gene promoters.
我们研究了鸡和小鼠α2（I）型胶原基因启动子对S1核酸酶的敏感性。当将这些DNA导入超螺旋质粒并用S1核酸酶消化时，在每个启动子中都发现了一个包含一个或多个切割位点的离散区域。通过S1位点与已知限制性内切酶切割位点的距离来定位这些S1切割位点。在鸡基因中，S1敏感区段位于转录起始位点之前180至200个碱基对处，而在小鼠启动子中，它位于-145至-165个碱基对之间。鸡启动子中的这个位点映射到先前已证明在染色质中对S1和DNase I高度敏感的区段。尽管在两个启动子中这些S1位点与转录起始位点的距离不同，但两个物种在这些位点的序列高度保守。每个序列由一个相同的串联重复组成，每个重复中包含一个短回文序列。由于DNA序列不具有有利于左手Z-DNA构型或十字形结构的特征，因此讨论了一种可以解释这些序列对S1敏感性的替代模型。这些序列的保守性及其对S1的敏感性表明它们在α2（I）型胶原基因启动子的激活或调控中起作用。
