Epshtein Vitaly, Toulmé Francine, Rahmouni A Rachid, Borukhov Sergei, Nudler Evgeny
Department of Biochemistry, New York University Medical Center, New York, NY 10016, USA.
EMBO J. 2003 Sep 15;22(18):4719-27. doi: 10.1093/emboj/cdg452.
During transcription, cellular RNA polymerases (RNAP) have to deal with numerous potential roadblocks imposed by various DNA binding proteins. Many such proteins partially or completely interrupt a single round of RNA chain elongation in vitro. Here we demonstrate that Escherichia coli RNAP can effectively read through the site-specific DNA-binding proteins in vitro and in vivo if more than one RNAP molecule is allowed to initiate from the same promoter. The anti-roadblock activity of the trailing RNAP does not require transcript cleavage activity but relies on forward translocation of roadblocked complexes. These results support a cooperation model of transcription whereby RNAP molecules behave as 'partners' helping one another to traverse intrinsic and extrinsic obstacles.
在转录过程中，细胞RNA聚合酶（RNAP）必须应对各种DNA结合蛋白带来的众多潜在障碍。许多这类蛋白在体外会部分或完全中断一轮RNA链的延伸。在这里我们证明，如果允许不止一个RNAP分子从同一个启动子起始，大肠杆菌RNAP在体外和体内都能有效地通读位点特异性DNA结合蛋白。尾随的RNAP的抗障碍活性不需要转录切割活性，而是依赖于被障碍阻碍的复合物的向前移位。这些结果支持了一种转录合作模型，即RNAP分子作为“伙伴”相互帮助穿越内在和外在障碍。
