非洲爪蟾TFIIIC与5S RNA基因的相互作用。

Sturges M R, Bartilson M, Peck L J

Sinsheimer Laboratories, University of California at Santa Cruz 95064, USA.

Nucleic Acids Res. 1995 May 11;23(9):1551-6. doi: 10.1093/nar/23.9.1551.

Using fractionated Xenopus transcription factors we have identified and characterized a unique protein-DNA complex formed between TFIIIA, TFIIIC and a 5S RNA gene. The formation of this complex was blocked by specific competitor DNAs and by the inactivation of TFIIIC using two different methods. In addition, TFIIIC activity was retained when the complexes were affinity purified using a reversibly immobilized DNA template. The TFIII(A+C)-5S RNA gene complex has a distinct electrophoretic mobility on band-shift gels and a unique DNase I footprint. The characteristic feature of the DNase I footprint is a TFIIIC-dependent extension of the TFIIIA footprint an additional 25 bp toward the 5' end of the gene. This indicates a direct interaction between Xenopus TFIIIC and the template DNA.

利用分离的非洲爪蟾转录因子，我们鉴定并表征了在TFIIIA、TFIIIC与一个5S RNA基因之间形成的独特蛋白质-DNA复合物。该复合物的形成被特异性竞争DNA以及通过两种不同方法使TFIIIC失活所阻断。此外，当使用可逆固定的DNA模板对复合物进行亲和纯化时，TFIIIC活性得以保留。TFIII(A + C)-5S RNA基因复合物在凝胶迁移实验中有独特的电泳迁移率以及独特的DNA酶I足迹。DNA酶I足迹的特征是TFIIIA足迹在TFIIIC依赖下向基因5'端额外延伸25个碱基对。这表明非洲爪蟾TFIIIC与模板DNA之间存在直接相互作用。