Moulin D S, Manson A L, Nuthall H N, Smith D J, Huxley C, Harris A
Institute of Molecular Medicine, Oxford University, John Radcliffe Hospital, U.K.
Mol Med. 1999 Apr;5(4):211-23.
The cystic fibrosis transmembrane conductance regulator gene (CFTR) shows a complex pattern of expression. The regulatory elements conferring tissue-specific and temporal regulation are thought to lie mainly outside the promoter region. Previously, we identified DNase I hypersensitive sites (DHS) that may contain regulatory elements associated with the CFTR gene at -79.5 and at -20.5 kb with respect to the ATG and at 10 kb into the first intron.
In order to evaluate these regulatory elements in vivo we examined these DHS in a human CFTR gene that was introduced on a yeast artificial chromosome (YAC) into transgenic mice. The 310 kb human CFTR YAC was shown to restore the pheno-type of CF-null mice and so is likely to contain most of the regulatory elements required for tissue-specific expression of CFTR.
We found that the YAC does not include the -79.5 kb region. The DHS at -20.5 kb is present in the chromatin of most tissues of the transgenic mice, supporting its non-tissue-specific nature. The DHS in the first intron is present in a more restricted set of tissues in the mice, although its presence does not show complete concordance with CFTR expression. The intron I DHS may be important for the higher levels of expression found in human pancreatic ducts and in lung submucosal glands.
These data support the in vivo importance of these regulatory elements.
囊性纤维化跨膜传导调节因子基因（CFTR）呈现出复杂的表达模式。赋予组织特异性和时间调控的调控元件被认为主要位于启动子区域之外。此前，我们鉴定出了脱氧核糖核酸酶I超敏位点（DHS），相对于ATG而言，这些位点可能包含与CFTR基因相关的调控元件，分别位于-79.5 kb和-20.5 kb处，以及第一个内含子内10 kb处。
为了在体内评估这些调控元件，我们在一个通过酵母人工染色体（YAC）导入转基因小鼠的人CFTR基因中检测了这些DHS。310 kb的人CFTR YAC被证明可恢复CF基因缺失小鼠的表型，因此可能包含CFTR组织特异性表达所需的大部分调控元件。
我们发现YAC不包括-79.5 kb区域。-20.5 kb处的DHS存在于转基因小鼠大多数组织的染色质中，这支持了其非组织特异性的性质。第一个内含子中的DHS在小鼠的一组更有限的组织中存在，尽管其存在与CFTR表达并不完全一致。内含子I的DHS对于在人胰管和肺黏膜下腺中发现的较高表达水平可能很重要。
这些数据支持了这些调控元件在体内的重要性。
