The DNA replication origin of plasmid NR1 is located approximately 190 base pairs downstream from the 3' end of the repA1 gene, which encodes the essential initiation protein for replication of the plasmid. Restriction endonuclease fragments that contain the NR1 replication origin and its flanking sequences at circularly permuted positions were obtained by digesting oligomers of ori-containing DNA fragments with sets of enzymes that each cut only once in every ori fragment. Polyacrylamide gel electrophoresis of these permuted restriction fragments showed anomalous mobilities, indicating the presence of a DNA bending locus. Through analysis of the relative mobility plots of these permuted fragments, we found one or two possible DNA bending sites located in the intervening region between the repA1 gene and the replication origin of NR1. It seems possible that DNA bending in this region might help to orient the replication origin alongside the repA1 gene, which could contribute to the cis-acting character of the RepA1 initiation protein.
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http://dx.doi.org/10.1128/jb.171.2.703-707.1989 | DOI Listing |
Nucleic Acids Res
January 2025
Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France.
Large vertebrate genomes duplicate by activating tens of thousands of DNA replication origins, irregularly spaced along the genome. The spatial and temporal regulation of the replication process is not yet fully understood. To investigate the DNA replication dynamics, we developed a methodology called RepliCorr, which uses the spatial correlation between replication patterns observed on stretched single-molecule DNA obtained by either DNA combing or high-throughput optical mapping.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Physiology and Biophysics, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States.
The Rep68 protein from Adeno-Associated Virus (AAV) is a multifunctional SF3 helicase that performs most of the DNA transactions necessary for the viral life cycle. During AAV DNA replication, Rep68 assembles at the origin of replication, catalyzing the DNA melting and nicking reactions during the hairpin rolling replication process to complete the second-strand synthesis of the AAV genome. We report the cryo-electron microscopy structures of Rep68 bound to the adeno-associated virus integration site 1 in different nucleotide-bound states.
View Article and Find Full Text PDFMol Cell Proteomics
January 2025
Center for Chromosome Stability, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark.
Accurate genome duplication requires a tightly regulated DNA replication program, which relies on the fine regulation of origin firing. While the molecular steps involved in origin firing have been determined predominantly in budding yeast, the complexity of this process in human cells has yet to be fully elucidated. Here, we describe a straightforward proteomics approach to systematically analyse protein recruitment to the chromatin during induced origin firing in human cells.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Department of Biomedical Engineering, Faculty of Engineering and Natural Sciences, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Türkiye.
Gene II Protein (Gp2/P2) is a nicking enzyme of the M13 bacteriophage that plays a role in the DNA replication of the viral genome. P2 recognizes a specific sequence at the f1 replication origin and nicks one of the strands and starts replication. This study was conducted to address the limitations of previous experiments, improve methodologies, and precisely determine the biochemical activity conditions of the P2 enzyme in vitro.
View Article and Find Full Text PDFBiology (Basel)
December 2024
Division of Biochemistry, Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University, Sendai 981-8558, Japan.
We propose a hypothesis for the simultaneous emergence of bacteria, archaea, viruses, and mobile elements by sequential and concrete biochemical pathways. The emergence process can be considered analogous to crystallization, where genetic and biochemical systems stabilize as organisms evolve from their common ancestor, the LUCA, which was a non-free-living pool of single operon type genomes including double-stranded (ds) DNA at an ancient submarine alkaline vent. Each dsDNA operon was transcribed by different systems in σ, TFIIB, or TBP genomes.
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