Nibu Y, Tanimoto K, Takahashi S, Ono H, Murakami K, Fukamizu A
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
Biochem Biophys Res Commun. 1994 Dec 15;205(2):1102-8. doi: 10.1006/bbrc.1994.2779.
We have recently characterized a cell type-dependent downstream enhancer that is contained within an 832-bp B2 sequences spanning the exon 5 and 3'-flanking region of the human angiotensinogen gene and have localized one of core elements to a 24-bp region in the 3'-flanking region. In the present study, we functionally dissected the 5'-half of B2 region and identified an additional cell type-dependent enhancer core element composed of the 80-bp sequences (+1399 to +1478) in the exon 5. Electrophoretic mobility shift assays demonstrated that the element interacts with two HepG2 cell-specific and several ubiquitous nuclear factors. These results, together with our previous results, suggest that the 80-bp exon 5 enhancer core element as well as 24-bp region plays an important role in the downstream enhancer effect.
我们最近鉴定了一种细胞类型依赖性下游增强子，它包含在跨越人血管紧张素原基因第5外显子和3'侧翼区域的832 bp B2序列中，并将其中一个核心元件定位到3'侧翼区域的一个24 bp区域。在本研究中，我们对B2区域的5'半部分进行了功能剖析，并在第5外显子中鉴定了一个由80 bp序列（+1399至+1478）组成的额外的细胞类型依赖性增强子核心元件。电泳迁移率变动分析表明，该元件与两种HepG2细胞特异性和几种普遍存在的核因子相互作用。这些结果与我们之前的结果一起表明，80 bp的第5外显子增强子核心元件以及24 bp区域在下游增强子效应中起重要作用。
