This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ishimi, Y Articles by Ohba, R Search for Related Content PubMed PubMed Citation Articles by Ishimi, Y Articles by Ohba, R

 Previous Article  |  Next Article 

Mol Cell Biol. 1994 October; 14(10): 6489-6496

DNA replication from initiation zones of mammalian cells in a model system.

Y Ishimi, K Matsumoto and R Ohba

Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.

ABSTRACT

We reported that DNA replication initiates from the region containing an autonomously replicating sequence from Saccharomyces cerevisiae when negatively supercoiled plasmid DNA is incubated with the proteins required for simian virus 40 DNA replication (Y. Ishimi and K. Matsumoto, Proc. Natl. Acad. Sci. USA 90:5399-5403, 1993). In this study, the DNAs containing initiation zones from mammalian cells were replicated in this model system. When negatively supercoiled DNA containing an initiation zone (2 kb) upstream of the human c-myc gene was incubated with simian virus 40 T antigen as a DNA helicase, HSSB (also called replication protein A), and DNA polymerase alpha-primase complex isolated from HeLa cells, DNA replication was specifically initiated from the center of the initiation zone, which was elongated bidirectionally in the presence of a DNA swivelase. Without HSSB, the level of DNA synthesis was significantly reduced and the localized initiation could not be detected, indicating that HSSB plays an essential role in the initiation of DNA replication. The digestion of negatively supercoiled template DNA with a single-strand-specific nuclease revealed that HSSB stimulated DNA unwinding in the center of the initiation zone where the DNA duplex is relatively unstable. In contrast, DNA replication started from a broad region of an initiation zone downstream of the dihydrofolate reductase gene from chinese hamster ovary cells, but the center of the region was mapped near the origin of bidirectional DNA replication. These results suggested that this system mimics a fundamental process of initiation of eukaryotic DNA replication. The mechanism of initiation is discussed.

---

Mol Cell Biol. 1994 October; 14(10): 6489-6496

This article has been cited by other articles:

• You, Z., Masai, H. (2005). DNA binding and helicase actions of mouse MCM4/6/7 helicase. Nucleic Acids Res 33: 3033-3047 [Abstract] [Full Text]  
• Ghosh, M., Liu, G., Randall, G., Bevington, J., Leffak, M. (2004). Transcription Factor Binding and Induced Transcription Alter Chromosomal c-myc Replicator Activity. Mol. Cell. Biol. 24: 10193-10207 [Abstract] [Full Text]  
• Kinoshita, Y., Johnson, E. M. (2004). Site-specific Loading of an MCM Protein Complex in a DNA Replication Initiation Zone Upstream of the c-MYC Gene in the HeLa Cell Cycle. J. Biol. Chem. 279: 35879-35889 [Abstract] [Full Text]  
• Malott, M., Leffak, M. (1999). Activity of the c-myc Replicator at an Ectopic Chromosomal Location. Mol. Cell. Biol. 19: 5685-5695 [Abstract] [Full Text]  
• Trowbridge, P. W., Roy, R., Simmons, D. T. (1999). Human Topoisomerase I Promotes Initiation of Simian Virus 40 DNA Replication In Vitro. Mol. Cell. Biol. 19: 1686-1694 [Abstract] [Full Text]  
• Ishimi, Y., Ichinose, S., Omori, A., Sato, K., Kimura, H. (1996). Binding of Human Minichromosome Maintenance Proteins with Histone H3. J. Biol. Chem. 271: 24115-24122 [Abstract] [Full Text]