Fedorov Anton V, Lukyanov Dmitry V, Podgornaya Olga I
Institute of Cytology, Russian Academy of Sciences, Tikhoretsky pr. 4, 194064 St-Petersburg, Russia.
Biochem Biophys Res Commun. 2006 Feb 10;340(2):553-9. doi: 10.1016/j.bbrc.2005.12.040. Epub 2005 Dec 19.
The initial step of LINE1 retrotransposons dissemination requires transcription from species-specific promoter located within 5'-untranslated region of LINE1. Although the 5'-untranslated region of the rat LINE1 element shows promoter activity, no promoter-binding proteins have been discovered so far. Using an EMSA and Southwestern blotting methods, we identified Sp1 and Sp3 proteins, which specifically bind to the rat LINE1 promoter in vitro. The Sp1/Sp3-binding motif within rat LINE1 promoter is located downstream of the major predicted transcription initiation site.
LINE1逆转录转座子传播的起始步骤需要从位于LINE1 5'-非翻译区内的物种特异性启动子进行转录。尽管大鼠LINE1元件的5'-非翻译区显示出启动子活性，但迄今为止尚未发现启动子结合蛋白。我们使用电泳迁移率变动分析（EMSA）和蛋白质印迹法（Southwestern blotting），鉴定出了能在体外特异性结合大鼠LINE1启动子的Sp1和Sp3蛋白。大鼠LINE1启动子内的Sp1/Sp3结合基序位于主要预测转录起始位点的下游。
