Abstract
Initiation of DNA replication in higher eukaryotes is still a matter of controversy. Some evidence suggests it occurs at specific sites. Data obtained using two-dimensional (2D) agarose gel electrophoresis, however, led to the notion that it may occur at random in broad zones. This hypothesis is primarily based on the observation that several contiguous DNA fragments generate a mixture of the so-called 'bubble' and 'simple Y' patterns in Neutral/neutral 2D gels. The interpretation that this mixture of hybridisation patterns is indicative for random initiation of DNA synthesis relies on the assumption that replicative intermediates (RIs) containing an internal bubble where initiation occurred at different relative positions, generate comigrating signals. The latter, however, is still to be proven. We investigated this problem by analysing together, in the same 2D gel, populations of pBR322 RIs that were digested with different restriction endonucleases that cut the monomer only once at different locations. DNA synthesis begins at a specific site in pBR322 and progresses in a uni-directional manner. Thus, the main difference between these sets of RIs was the relative position of the origin. The results obtained clearly showed that populations of RIs containing an internal bubble where initiation occurred at different relative positions do not generate signals that co-migrate all-the-way in 2D gels. Despite this observation, however, our results support the notion that random initiation is indeed responsible for the peculiar 'bubble' signal observed in the case of several metazoan eukaryotes.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bell L., Byers B. Separation of branched from linear DNA by two-dimensional gel electrophoresis. Anal Biochem. 1983 Apr 15;130(2):527–535. doi: 10.1016/0003-2697(83)90628-0. [DOI] [PubMed] [Google Scholar]
- Bell S. P., Stillman B. ATP-dependent recognition of eukaryotic origins of DNA replication by a multiprotein complex. Nature. 1992 May 14;357(6374):128–134. doi: 10.1038/357128a0. [DOI] [PubMed] [Google Scholar]
- Brewer B. J., Fangman W. L. The localization of replication origins on ARS plasmids in S. cerevisiae. Cell. 1987 Nov 6;51(3):463–471. doi: 10.1016/0092-8674(87)90642-8. [DOI] [PubMed] [Google Scholar]
- Burhans W. C., Vassilev L. T., Caddle M. S., Heintz N. H., DePamphilis M. L. Identification of an origin of bidirectional DNA replication in mammalian chromosomes. Cell. 1990 Sep 7;62(5):955–965. doi: 10.1016/0092-8674(90)90270-o. [DOI] [PubMed] [Google Scholar]
- Challberg M. D., Kelly T. J. Animal virus DNA replication. Annu Rev Biochem. 1989;58:671–717. doi: 10.1146/annurev.bi.58.070189.003323. [DOI] [PubMed] [Google Scholar]
- Deshpande A. M., Newlon C. S. The ARS consensus sequence is required for chromosomal origin function in Saccharomyces cerevisiae. Mol Cell Biol. 1992 Oct;12(10):4305–4313. doi: 10.1128/mcb.12.10.4305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Diffley J. F., Cocker J. H. Protein-DNA interactions at a yeast replication origin. Nature. 1992 May 14;357(6374):169–172. doi: 10.1038/357169a0. [DOI] [PubMed] [Google Scholar]
- Hamlin J. L. Mammalian origins of replication. Bioessays. 1992 Oct;14(10):651–659. doi: 10.1002/bies.950141002. [DOI] [PubMed] [Google Scholar]
- Handeli S., Klar A., Meuth M., Cedar H. Mapping replication units in animal cells. Cell. 1989 Jun 16;57(6):909–920. doi: 10.1016/0092-8674(89)90329-2. [DOI] [PubMed] [Google Scholar]
- Harland R. M., Laskey R. A. Regulated replication of DNA microinjected into eggs of Xenopus laevis. Cell. 1980 Oct;21(3):761–771. doi: 10.1016/0092-8674(80)90439-0. [DOI] [PubMed] [Google Scholar]
- Heinzel S. S., Krysan P. J., Tran C. T., Calos M. P. Autonomous DNA replication in human cells is affected by the size and the source of the DNA. Mol Cell Biol. 1991 Apr;11(4):2263–2272. doi: 10.1128/mcb.11.4.2263. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Huberman J. A., Spotila L. D., Nawotka K. A., el-Assouli S. M., Davis L. R. The in vivo replication origin of the yeast 2 microns plasmid. Cell. 1987 Nov 6;51(3):473–481. doi: 10.1016/0092-8674(87)90643-x. [DOI] [PubMed] [Google Scholar]
- Hyrien O., Méchali M. Plasmid replication in Xenopus eggs and egg extracts: a 2D gel electrophoretic analysis. Nucleic Acids Res. 1992 Apr 11;20(7):1463–1469. doi: 10.1093/nar/20.7.1463. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koo H. S., Wu H. M., Crothers D. M. DNA bending at adenine . thymine tracts. Nature. 1986 Apr 10;320(6062):501–506. doi: 10.1038/320501a0. [DOI] [PubMed] [Google Scholar]
- Krysan P. J., Calos M. P. Replication initiates at multiple locations on an autonomously replicating plasmid in human cells. Mol Cell Biol. 1991 Mar;11(3):1464–1472. doi: 10.1128/mcb.11.3.1464. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mahbubani H. M., Paull T., Elder J. K., Blow J. J. DNA replication initiates at multiple sites on plasmid DNA in Xenopus egg extracts. Nucleic Acids Res. 1992 Apr 11;20(7):1457–1462. doi: 10.1093/nar/20.7.1457. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martín-Parras L., Hernández P., Martínez-Robles M. L., Schvartzman J. B. Initiation of DNA replication in ColE1 plasmids containing multiple potential origins of replication. J Biol Chem. 1992 Nov 5;267(31):22496–22505. [PubMed] [Google Scholar]
- Martín-Parras L., Hernández P., Martínez-Robles M. L., Schvartzman J. B. Unidirectional replication as visualized by two-dimensional agarose gel electrophoresis. J Mol Biol. 1991 Aug 20;220(4):843–853. doi: 10.1016/0022-2836(91)90357-c. [DOI] [PubMed] [Google Scholar]
- Mecsas J., Sugden B. Replication of plasmids derived from bovine papilloma virus type 1 and Epstein-Barr virus in cells in culture. Annu Rev Cell Biol. 1987;3:87–108. doi: 10.1146/annurev.cb.03.110187.000511. [DOI] [PubMed] [Google Scholar]
- Schvartzman J. B., Adolph S., Martín-Parras L., Schildkraut C. L. Evidence that replication initiates at only some of the potential origins in each oligomeric form of bovine papillomavirus type 1 DNA. Mol Cell Biol. 1990 Jun;10(6):3078–3086. doi: 10.1128/mcb.10.6.3078. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shinomiya T., Ina S. Analysis of chromosomal replicons in early embryos of Drosophila melanogaster by two-dimensional gel electrophoresis. Nucleic Acids Res. 1991 Jul 25;19(14):3935–3941. doi: 10.1093/nar/19.14.3935. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Symington L. S. Double-strand-break repair and recombination catalyzed by a nuclear extract of Saccharomyces cerevisiae. EMBO J. 1991 Apr;10(4):987–996. doi: 10.1002/j.1460-2075.1991.tb08033.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Umek R. M., Kowalski D. The DNA unwinding element in a yeast replication origin functions independently of easily unwound sequences present elsewhere on a plasmid. Nucleic Acids Res. 1990 Nov 25;18(22):6601–6605. doi: 10.1093/nar/18.22.6601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vassilev L. T., Burhans W. C., DePamphilis M. L. Mapping an origin of DNA replication at a single-copy locus in exponentially proliferating mammalian cells. Mol Cell Biol. 1990 Sep;10(9):4685–4689. doi: 10.1128/mcb.10.9.4685. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vaughn J. P., Dijkwel P. A., Hamlin J. L. Replication initiates in a broad zone in the amplified CHO dihydrofolate reductase domain. Cell. 1990 Jun 15;61(6):1075–1087. doi: 10.1016/0092-8674(90)90071-l. [DOI] [PubMed] [Google Scholar]
- Wu H. M., Crothers D. M. The locus of sequence-directed and protein-induced DNA bending. Nature. 1984 Apr 5;308(5959):509–513. doi: 10.1038/308509a0. [DOI] [PubMed] [Google Scholar]