Lennard A C, Matthes H W, Egly J M, Chambon P
Unité 184 de Biologie Moléculaire et de Génie Génétique de l'INSERM, Institut de Chimie Biologique, Faculté de Médecine, Strasbourg, France.
Nucleic Acids Res. 1989 Sep 12;17(17):6903-14. doi: 10.1093/nar/17.17.6903.
Spacing mutations have been constructed between an SV40 72 bp enhancer element and the Adenovirus-2 major late promoter upstream element (Ad2MLP-UE), the Ad2MLP-UE and the Ad2MLP TATA-box and the SV40 72 bp enhancer and the TATA-box in the absence of the Ad2MLP-UE. A clear periodic pattern of transcription from the Ad2MLP was obtained by inserting multiples of half of a DNA turn between the SV40 enhancer and the Ad2MLP-UE. We interpret this as a stereospecific requirement for the spatial alignment between the enhancer element and either the Ad2MLP-UE or the TATA-box. Insertions between the upstream element and the TATA-box did not give a periodic transcription pattern, though insertion of half of a DNA turn increased the steady-state level of specific RNA. Unexpectedly, spacing mutations between the enhancer and TATA-box in which the upstream element had been point mutated gave indications of stereospecificity, whereas the same insertions with a deleted upstream element showed little requirement for a precise stereoalignment.
在SV40 72 bp增强子元件与腺病毒2型主要晚期启动子上游元件（Ad2MLP - UE）之间、Ad2MLP - UE与Ad2MLP TATA盒之间以及在没有Ad2MLP - UE的情况下SV40 72 bp增强子与TATA盒之间构建了间隔突变。通过在SV40增强子与Ad2MLP - UE之间插入DNA螺旋半圈的倍数，获得了来自Ad2MLP的清晰的周期性转录模式。我们将此解释为增强子元件与Ad2MLP - UE或TATA盒之间空间排列的立体特异性要求。尽管插入DNA螺旋半圈增加了特定RNA的稳态水平，但在上游元件与TATA盒之间的插入并未产生周期性转录模式。出乎意料的是，其中上游元件已发生点突变的增强子与TATA盒之间的间隔突变显示出立体特异性迹象，而相同插入且上游元件缺失的情况对精确立体排列的要求很低。
