Janson L, Bark C, Pettersson U
Nucleic Acids Res. 1987 Jul 10;15(13):4997-5016. doi: 10.1093/nar/15.13.4997.
Protein/DNA interactions in the human U2 RNA gene enhancer have been characterized by DNase I footprint and DMS methylation protection analyses. Nuclear factors present in both HeLa and B cell extracts have been shown to protect an approximately 70 bp region from DNase I digestion. DMS and DNase I footprint competition studies demonstrated that the entire footprint can be accounted for by interactions with two previously identified transcription factors. One of these recognizes the so called octanucleotide-motif ATGCAAAT (transcription factor IgNF-A) which has been shown to be essential for transcription. The other is the transcription factor Sp1 which binds to three target sequences located adjacent to the octameric motif. The Sp1 interactions appear to be required for full transcriptional activity. No differences in the DNase I footprint patterns or in the DMS methylation protections were observed when nuclear extracts from HeLa cells, two different B cell lines, or from the adenovirus-transformed 293 cell line were compared.
人类U2 RNA基因增强子中的蛋白质/DNA相互作用已通过DNA酶I足迹法和二甲基亚砜（DMS）甲基化保护分析进行了表征。已证明，HeLa细胞和B细胞提取物中存在的核因子可保护一个约70 bp的区域免受DNA酶I的消化。DMS和DNA酶I足迹竞争研究表明，整个足迹可通过与两个先前鉴定的转录因子的相互作用来解释。其中一个识别所谓的八核苷酸基序ATGCAAAT（转录因子IgNF-A），该基序已被证明对转录至关重要。另一个是转录因子Sp1，它与位于八聚体基序相邻的三个靶序列结合。Sp1的相互作用似乎是充分转录活性所必需的。当比较HeLa细胞、两种不同的B细胞系或腺病毒转化的293细胞系的核提取物时，未观察到DNA酶I足迹模式或DMS甲基化保护方面的差异。
