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PLoS Genetics Sep 2019In all kingdoms of life, DNA is used to encode hereditary information. Propagation of the genetic material between generations requires timely and accurate duplication... (Review)
Review
In all kingdoms of life, DNA is used to encode hereditary information. Propagation of the genetic material between generations requires timely and accurate duplication of DNA by semiconservative replication prior to cell division to ensure each daughter cell receives the full complement of chromosomes. DNA synthesis of daughter strands starts at discrete sites, termed replication origins, and proceeds in a bidirectional manner until all genomic DNA is replicated. Despite the fundamental nature of these events, organisms have evolved surprisingly divergent strategies that control replication onset. Here, we discuss commonalities and differences in replication origin organization and recognition in the three domains of life.
Topics: Biological Evolution; Cell Division; Chromosomes; DNA Replication; Evolution, Molecular; Replication Origin; Replicon
PubMed: 31513569
DOI: 10.1371/journal.pgen.1008320 -
Molecular Cell Feb 2023Errors occurring during DNA replication can result in inaccurate replication, incomplete replication, or re-replication, resulting in genome instability that can lead to... (Review)
Review
Errors occurring during DNA replication can result in inaccurate replication, incomplete replication, or re-replication, resulting in genome instability that can lead to diseases such as cancer or disorders such as autism. A great deal of progress has been made toward understanding the entire process of DNA replication in eukaryotes, including the mechanism of initiation and its control. This review focuses on the current understanding of how the origin recognition complex (ORC) contributes to determining the location of replication initiation in the multiple chromosomes within eukaryotic cells, as well as methods for mapping the location and temporal patterning of DNA replication. Origin specification and configuration vary substantially between eukaryotic species and in some cases co-evolved with gene-silencing mechanisms. We discuss the possibility that centromeres and origins of DNA replication were originally derived from a common element and later separated during evolution.
Topics: Centromere; DNA Replication; Origin Recognition Complex; Replication Origin; Saccharomyces cerevisiae
PubMed: 36640769
DOI: 10.1016/j.molcel.2022.12.024 -
Science (New York, N.Y.) Nov 2021Molecular virology tools are critical for basic studies of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and for developing new therapeutics....
Molecular virology tools are critical for basic studies of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and for developing new therapeutics. Experimental systems that do not rely on viruses capable of spread are needed for potential use in lower-containment settings. In this work, we use a yeast-based reverse genetics system to develop spike-deleted SARS-CoV-2 self-replicating RNAs. These noninfectious self-replicating RNAs, or replicons, can be trans-complemented with viral glycoproteins to generate replicon delivery particles for single-cycle delivery into a range of cell types. This SARS-CoV-2 replicon system represents a convenient and versatile platform for antiviral drug screening, neutralization assays, host factor validation, and viral variant characterization.
Topics: Animals; Antibodies, Neutralizing; Antibodies, Viral; Antiviral Agents; Cell Line; Humans; Interferons; Microbial Sensitivity Tests; Mutation; Plasmids; RNA, Viral; Replicon; Reverse Genetics; SARS-CoV-2; Saccharomyces cerevisiae; Spike Glycoprotein, Coronavirus; Viral Nonstructural Proteins; Viral Pseudotyping; Virion; Virus Replication
PubMed: 34648371
DOI: 10.1126/science.abj8430 -
Biochemical and Biophysical Research... Dec 2022Nearly 70 years after the proposal of semiconservative replication of generic material by Watson and Crick, we now understand many of the proteins involved in the... (Review)
Review
Nearly 70 years after the proposal of semiconservative replication of generic material by Watson and Crick, we now understand many of the proteins involved in the replication of host chromosomes and how they operate. The initiator and replicator, proposed in the replicon hypothesis, are now well defined in both prokaryotes and eukaryotes. On the other hand, studies in prokaryotes and Archaea indicate alternative modes of initiation, which may not depend on an initiator. Here I summarize recent progress in the field of DNA replication and discuss the evolution of replication systems.
Topics: Replication Origin; DNA Replication; Escherichia coli; DNA-Binding Proteins; Replicon; Bacterial Proteins; Chromosomes, Bacterial; DNA, Bacterial
PubMed: 36344169
DOI: 10.1016/j.bbrc.2022.09.060 -
Microbiology Spectrum Apr 2015Serine resolvases are an interesting group of site-specific recombinases that, in their native contexts, resolve large fused replicons into smaller separated ones. Some... (Review)
Review
Serine resolvases are an interesting group of site-specific recombinases that, in their native contexts, resolve large fused replicons into smaller separated ones. Some resolvases are encoded by replicative transposons and resolve the transposition product, in which the donor and recipient molecules are fused, into separate replicons. Other resolvases are encoded by plasmids and function to resolve plasmid dimers into monomers. Both types are therefore involved in the spread and maintenance of antibiotic-resistance genes. Resolvases and the closely related invertases were the first serine recombinases to be studied in detail, and much of our understanding of the unusual strand exchange mechanism of serine recombinases is owed to those early studies. Resolvases and invertases have also served as paradigms for understanding how DNA topology can be harnessed to regulate enzyme activity. Finally, their relatively modular structure, combined with a wealth of structural and biochemical data, has made them good choices for engineering chimeric recombinases with designer specificity. This chapter focuses on the current understanding of serine resolvases, with a focus on the contributions of structural studies.
Topics: DNA; DNA Transposable Elements; Plasmids; Recombinases; Recombination, Genetic; Replicon; Substrate Specificity
PubMed: 26104713
DOI: 10.1128/microbiolspec.MDNA3-0045-2014 -
Microbial Genomics Aug 2018Large-scale bacterial population genetics studies are now routine due to cost-effective Illumina short-read sequencing. However, analysing plasmid content remains...
Large-scale bacterial population genetics studies are now routine due to cost-effective Illumina short-read sequencing. However, analysing plasmid content remains difficult due to incomplete assembly of plasmids. Bacterial isolates can contain any number of plasmids and assembly remains complicated due to the presence of repetitive elements. Numerous tools have been developed to analyse plasmids but the performance and functionality of the tools are variable. The MOB-suite was developed as a set of modular tools for reconstruction and typing of plasmids from draft assembly data to facilitate characterization of plasmids. Using a set of closed genomes with publicly available Illumina data, the MOB-suite identified contigs of plasmid origin with both high sensitivity and specificity (95 and 88 %, respectively). In comparison, plasmidfinder demonstrated high specificity (99 %) but limited sensitivity (50 %). Using the same dataset of 377 known plasmids, MOB-recon accurately reconstructed 207 plasmids so that they were assigned to a single grouping without other plasmid or chromosomal sequences, whereas plasmidSPAdes was only able to accurately reconstruct 102 plasmids. In general, plasmidSPAdes has a tendency to merge different plasmids together, with 208 plasmids undergoing merge events. The MOB-suite reduces the number of errors but produces more hybrid plasmids, with 84 plasmids undergoing both splits and merges. The MOB-suite also provides replicon typing similar to plasmidfinder but with the inclusion of relaxase typing and prediction of conjugation potential. The MOB-suite is written in Python 3 and is available from https://github.com/phac-nml/mob-suite.
Topics: Bacteria; Genome, Bacterial; Plasmids; Replicon; Sequence Analysis, DNA; Software
PubMed: 30052170
DOI: 10.1099/mgen.0.000206 -
Antimicrobial Agents and Chemotherapy Jul 2014In the work presented here, we designed and developed two easy-to-use Web tools for in silico detection and characterization of whole-genome sequence (WGS) and...
In the work presented here, we designed and developed two easy-to-use Web tools for in silico detection and characterization of whole-genome sequence (WGS) and whole-plasmid sequence data from members of the family Enterobacteriaceae. These tools will facilitate bacterial typing based on draft genomes of multidrug-resistant Enterobacteriaceae species by the rapid detection of known plasmid types. Replicon sequences from 559 fully sequenced plasmids associated with the family Enterobacteriaceae in the NCBI nucleotide database were collected to build a consensus database for integration into a Web tool called PlasmidFinder that can be used for replicon sequence analysis of raw, contig group, or completely assembled and closed plasmid sequencing data. The PlasmidFinder database currently consists of 116 replicon sequences that match with at least at 80% nucleotide identity all replicon sequences identified in the 559 fully sequenced plasmids. For plasmid multilocus sequence typing (pMLST) analysis, a database that is updated weekly was generated from www.pubmlst.org and integrated into a Web tool called pMLST. Both databases were evaluated using draft genomes from a collection of Salmonella enterica serovar Typhimurium isolates. PlasmidFinder identified a total of 103 replicons and between zero and five different plasmid replicons within each of 49 S. Typhimurium draft genomes tested. The pMLST Web tool was able to subtype genomic sequencing data of plasmids, revealing both known plasmid sequence types (STs) and new alleles and ST variants. In conclusion, testing of the two Web tools using both fully assembled plasmid sequences and WGS-generated draft genomes showed them to be able to detect a broad variety of plasmids that are often associated with antimicrobial resistance in clinically relevant bacterial pathogens.
Topics: Computer Simulation; Databases, Genetic; Drug Resistance, Bacterial; Enterobacteriaceae; Genome, Bacterial; Internet; Multilocus Sequence Typing; Plasmids; Replicon; Reproducibility of Results
PubMed: 24777092
DOI: 10.1128/AAC.02412-14 -
Cell Jan 2023In eukaryotes, DNA replication initiation requires assembly and activation of the minichromosome maintenance (MCM) 2-7 double hexamer (DH) to melt origin DNA strands....
In eukaryotes, DNA replication initiation requires assembly and activation of the minichromosome maintenance (MCM) 2-7 double hexamer (DH) to melt origin DNA strands. However, the mechanism for this initial melting is unknown. Here, we report a 2.59-Å cryo-electron microscopy structure of the human MCM-DH (hMCM-DH), also known as the pre-replication complex. In this structure, the hMCM-DH with a constricted central channel untwists and stretches the DNA strands such that almost a half turn of the bound duplex DNA is distorted with 1 base pair completely separated, generating an initial open structure (IOS) at the hexamer junction. Disturbing the IOS inhibits DH formation and replication initiation. Mapping of hMCM-DH footprints indicates that IOSs are distributed across the genome in large clusters aligning well with initiation zones designed for stochastic origin firing. This work unravels an intrinsic mechanism that couples DH formation with initial DNA melting to license replication initiation in human cells.
Topics: Humans; Cell Cycle Proteins; Cryoelectron Microscopy; DNA Replication; DNA-Binding Proteins; Minichromosome Maintenance Proteins; Replication Origin
PubMed: 36608662
DOI: 10.1016/j.cell.2022.12.008 -
Methods in Molecular Biology (Clifton,... 2017Self-replicating RNA derived from the genomes of positive strand RNA viruses represents a powerful tool for both molecular studies on virus biology and approaches to... (Review)
Review
Self-replicating RNA derived from the genomes of positive strand RNA viruses represents a powerful tool for both molecular studies on virus biology and approaches to novel safe and effective vaccines. The following chapter summarizes the principles how such RNAs can be established and used for design of vaccines. Due to the large variety of strategies needed to circumvent specific pitfalls in the design of such constructs the technical details of the experiments are not described here but can be found in the cited literature.
Topics: Animals; Humans; RNA Viruses; RNA, Viral; Replicon; Vaccines
PubMed: 27987141
DOI: 10.1007/978-1-4939-6481-9_2 -
International Journal of Molecular... Sep 2019Maintenance of genome integrity is a key process in all organisms. DNA polymerases (Pols) are central players in this process as they are in charge of the faithful... (Review)
Review
Maintenance of genome integrity is a key process in all organisms. DNA polymerases (Pols) are central players in this process as they are in charge of the faithful reproduction of the genetic information, as well as of DNA repair. Interestingly, all eukaryotes possess a large repertoire of polymerases. Three protein complexes, DNA Pol α, δ, and ε, are in charge of nuclear DNA replication. These enzymes have the fidelity and processivity required to replicate long DNA sequences, but DNA lesions can block their progression. Consequently, eukaryotic genomes also encode a variable number of specialized polymerases (between five and 16 depending on the organism) that are involved in the replication of damaged DNA, DNA repair, and organellar DNA replication. This diversity of enzymes likely stems from their ability to bypass specific types of lesions. In the past 10-15 years, our knowledge regarding plant DNA polymerases dramatically increased. In this review, we discuss these recent findings and compare acquired knowledge in plants to data obtained in other eukaryotes. We also discuss the emerging links between genome and epigenome replication.
Topics: DNA Damage; DNA Repair; DNA Replication; DNA-Directed DNA Polymerase; Epigenomics; Genome, Plant; Meiosis; Plants; Protein Subunits; Replication Origin; Signal Transduction; Stress, Physiological
PubMed: 31569730
DOI: 10.3390/ijms20194814