Two cellular transcription factors, nuclear factor I (NFI) and octamer binding protein (Oct-1), bind simultaneously to their recognition sequences in the Ad5 origin of replication thereby enhancing initiation. Using scanning force microscopy we have previously shown that NFI induces a 60° bend in the origin DNA. Here we demonstrate that Oct-1 induces a 42° bend in the origin DNA. Simultaneous binding of NFI and Oct-1 induces an 82° collective bend suggesting that both bends are oriented towards each other. In functional replication assays we further demonstrate that this extensive DNA bending leads to a synergistic enhancement of DNA replication. We propose that collective DNA bending induced by NFI and Oct-1 facilitates the optimal assembly of the preinitiation complex and plays an important role in the stimulatory mechanism of NFI and Oct-1 in replication.

doi.org/10.1093/nar/gkh944, hdl.handle.net/1765/57289
Nucleic Acids Research
Department of Molecular Genetics

Mysiak, M., Wyman, C., Holthuizen, P. E., & van der Vliet, P. (2004). NFI and Oct-1 bend the Ad5 origin in the same direction leading to optimal DNA replication. Nucleic Acids Research, 32(21), 6218–6225. doi:10.1093/nar/gkh944