DNA replication in thermophiles

2004 ◽  
Vol 32 (2) ◽  
pp. 236-239 ◽  
Author(s):  
A.I. Majerník ◽  
E.R. Jenkinson ◽  
J.P.J. Chong
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Molecular Mechanisms ◽  
Pyrococcus Furiosus ◽  
Model Systems ◽  
Eukaryotic Cells ◽  
Dna Manipulation ◽  
Processing Enzymes ◽  
The Many ◽  
Thermophilic Archaea

DNA replication enzymes in the thermophilic Archaea have previously attracted attention due to their obvious use in methods such as PCR. The proofreading ability of the Pyrococcus furiosus DNA polymerase has resulted in a commercially successful product (Pfu polymerase). One of the many notable features of the Archaea is the fact that their DNA processing enzymes appear on the whole to be more like those found in eukaryotes than bacteria. These proteins also appear to be simpler versions of those found in eukaryotes. For these reasons, archaeal organisms make potentially interesting model systems to explore the molecular mechanisms of processes such as DNA replication, repair and recombination. Why archaeal DNA-manipulation systems were adopted over bacterial systems by eukaryotic cells remains a most interesting question that we suggest may be linked to thermophily.

scholarly journals DNA Helicase–Polymerase Coupling in Bacteriophage DNA Replication

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1739
Author(s):  
Chen-Yu Lo ◽  
Yang Gao
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Molecular Mechanisms ◽  
Bacteriophage T4 ◽  
Dna Helicase ◽  
Model Systems ◽  
Genome Replication ◽  
Template Strand ◽  
Replication Systems ◽  
Mechanistic Basis

Bacteriophages have long been model systems to study the molecular mechanisms of DNA replication. During DNA replication, a DNA helicase and a DNA polymerase cooperatively unwind the parental DNA. By surveying recent data from three bacteriophage replication systems, we summarized the mechanistic basis of DNA replication by helicases and polymerases. Kinetic data have suggested that a polymerase or a helicase alone is a passive motor that is sensitive to the base-pairing energy of the DNA. When coupled together, the helicase–polymerase complex is able to unwind DNA actively. In bacteriophage T7, helicase and polymerase reside right at the replication fork where the parental DNA is separated into two daughter strands. The two motors pull the two daughter strands to opposite directions, while the polymerase provides a separation pin to split the fork. Although independently evolved and containing different replisome components, bacteriophage T4 replisome shares mechanistic features of Hel–Pol coupling that are similar to T7. Interestingly, in bacteriophages with a limited size of genome like Φ29, DNA polymerase itself can form a tunnel-like structure, which encircles the DNA template strand and facilitates strand displacement synthesis in the absence of a helicase. Studies on bacteriophage replication provide implications for the more complicated replication systems in bacteria, archaeal, and eukaryotic systems, as well as the RNA genome replication in RNA viruses.

PolA2 is required for embryo development in ArabidopsisThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 626-634 ◽  
Author(s):  
Hui Yang ◽  
Daoquan Xiang ◽  
Sathya Prakash Venglat ◽  
Yongguo Cao ◽  
Edwin Wang ◽  
...  
Keyword(s):  
Dna Replication ◽  
Embryo Development ◽  
Dna Polymerase ◽  
Apical Cell ◽  
National Research Council ◽  
Model Systems ◽  
Proper Function ◽  
Dna Polymerase Α ◽  
Insertional Inactivation ◽  
Embryo Lethality

DNA replication machinery is highly conserved in eukaryotes. DNA polymerase is essential for the synthesis of new DNA strands and for DNA repair. Despite the significant progress in the understanding of these processes in yeast and animal model systems, there is only scant information available for their counterparts in plants. Among different multisubunit-containing DNA polymerases, DNA polymerase α (POLA complex) is composed of four subunits. In this study, we report on the characterization of PolA2, which encodes the putative B subunit of DNA polymerase α in Arabidopsis thaliana (L.) Heynh. PolA2 is a single copy gene in Arabidopsis and shows highly conserved regions with putative homologs in other plant species. Insertional inactivation of PolA2 in Arabidopsis leads to embryo lethality, with developmental arrest at or before the four-cell stage during embryogenesis. The apical cell lineage is strongly affected in the mutant embryos and the endosperm initial cell fails to divide. PolA2 is expressed broadly in the early phases of embryo development during the period of active cell divisions, while during the later stages of development expression is reduced and more localized. Ectopic overexpression of PolA2 produced dominant negative phenotypes with gametic and embryo lethality suggesting that coordinated and parallel expression with other subunits is critical for its proper function in DNA replication and plant development.

scholarly journals Archaeal DNA Replication: Identifying the Pieces to Solve a Puzzle

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1249-1267 ◽  
Author(s):  
Isaac K O Cann ◽  
Yoshizumi Ishino
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Pyrococcus Furiosus ◽  
Sequence Similarity ◽  
Large Subunit ◽  
Dna Polymerases ◽  
Small Subunit ◽  
Accessory Proteins ◽  
Pol Ii

Abstract Archaeal organisms are currently recognized as very exciting and useful experimental materials. A major challenge to molecular biologists studying the biology of Archaea is their DNA replication mechanism. Undoubtedly, a full understanding of DNA replication in Archaea requires the identification of all the proteins involved. In each of four completely sequenced genomes, only one DNA polymerase (Pol BI proposed in this review from family B enzyme) was reported. This observation suggested that either a single DNA polymerase performs the task of replicating the genome and repairing the mutations or these genomes contain other DNA polymerases that cannot be identified by amino acid sequence. Recently, a heterodimeric DNA polymerase (Pol II, or Pol D as proposed in this review) was discovered in the hyperthermophilic archaeon, Pyrococcus furiosus. The genes coding for DP1 and DP2, the subunits of this DNA polymerase, are highly conserved in the Euryarchaeota. Euryarchaeotic DP1, the small subunit of Pol II (Pol D), has sequence similarity with the small subunit of eukaryotic DNA polymerase δ. DP2 protein, the large subunit of Pol II (Pol D), seems to be a catalytic subunit. Despite possessing an excellent primer extension ability in vitro, Pol II (Pol D) may yet require accessory proteins to perform all of its functions in euryarchaeotic cells. This review summarizes our present knowledge about archaeal DNA polymerases and their relationship with those accessory proteins, which were predicted from the genome sequences.

scholarly journals Archaeal DNA polymerases: new frontiers in DNA replication and repair

2018 ◽  
Vol 2 (4) ◽  
pp. 503-516 ◽  
Author(s):  
Christopher D.O. Cooper
Keyword(s):  
Dna Repair ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Dna Amplification ◽  
Model Systems ◽  
Genome Replication ◽  
Sequencing Technologies ◽  
Dna Replication And Repair ◽  
Polymerase Chain

Archaeal DNA polymerases have long been studied due to their superior properties for DNA amplification in the polymerase chain reaction and DNA sequencing technologies. However, a full comprehension of their functions, recruitment and regulation as part of the replisome during genome replication and DNA repair lags behind well-established bacterial and eukaryotic model systems. The archaea are evolutionarily very broad, but many studies in the major model systems of both Crenarchaeota and Euryarchaeota are starting to yield significant increases in understanding of the functions of DNA polymerases in the respective phyla. Recent advances in biochemical approaches and in archaeal genetic models allowing knockout and epitope tagging have led to significant increases in our understanding, including DNA polymerase roles in Okazaki fragment maturation on the lagging strand, towards reconstitution of the replisome itself. Furthermore, poorly characterised DNA polymerase paralogues are finding roles in DNA repair and CRISPR immunity. This review attempts to provide a current update on the roles of archaeal DNA polymerases in both DNA replication and repair, addressing significant questions that remain for this field.

scholarly journals The GINS Complex from Pyrococcus furiosus Stimulates the MCM Helicase Activity

2007 ◽  
Vol 283 (3) ◽  
pp. 1601-1609 ◽  
Author(s):  
Takehiro Yoshimochi ◽  
Ryosuke Fujikane ◽  
Miyuki Kawanami ◽  
Fujihiko Matsunaga ◽  
Yoshizumi Ishino
Keyword(s):  
Dna Replication ◽  
Pyrococcus Furiosus ◽  
Dna Helicase ◽  
Hyperthermophilic Archaea ◽  
Eukaryotic Cells ◽  
Exponential Growth Phase ◽  
Chromosomal Dna ◽  
Mcm Helicase ◽  
Related Proteins

Pyrococcus furiosus, a hyperthermophilic Archaea, has homologs of the eukaryotic MCM (mini-chromosome maintenance) helicase and GINS complex. The MCM and GINS proteins are both essential factors to initiate DNA replication in eukaryotic cells. Many biochemical characterizations of the replication-related proteins have been reported, but it has not been proved that the homologs of each protein are also essential for replication in archaeal cells. Here, we demonstrated that the P. furiosus GINS complex interacts with P. furiosus MCM. A chromatin immunoprecipitation assay revealed that the GINS complex is detected preferentially at the oriC region on Pyrococcus chromosomal DNA during the exponential growth phase but not in the stationary phase. Furthermore, the GINS complex stimulates both the ATPase and DNA helicase activities of MCM in vitro. These results strongly suggest that the archaeal GINS is involved in both the initiation and elongation processes of DNA replication in P. furiosus, as observed in eukaryotic cells.

scholarly journals Molecular mechanisms of eukaryotic origin initiation, replication fork progression, and chromatin maintenance

2020 ◽  
Vol 477 (18) ◽  
pp. 3499-3525
Author(s):  
Zuanning Yuan ◽  
Huilin Li
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Replication Fork ◽  
Dna Methyltransferase ◽  
Molecular Mechanisms ◽  
Methylation Pattern ◽  
Replication Initiation ◽  
Nucleosome Assembly ◽  
Epigenetic Information ◽  
Eukaryotic Origin

Eukaryotic DNA replication is a highly dynamic and tightly regulated process. Replication involves several dozens of replication proteins, including the initiators ORC and Cdc6, replicative CMG helicase, DNA polymerase α-primase, leading-strand DNA polymerase ε, and lagging-strand DNA polymerase δ. These proteins work together in a spatially and temporally controlled manner to synthesize new DNA from the parental DNA templates. During DNA replication, epigenetic information imprinted on DNA and histone proteins is also copied to the daughter DNA to maintain the chromatin status. DNA methyltransferase 1 is primarily responsible for copying the parental DNA methylation pattern into the nascent DNA. Epigenetic information encoded in histones is transferred via a more complex and less well-understood process termed replication-couple nucleosome assembly. Here, we summarize the most recent structural and biochemical insights into DNA replication initiation, replication fork elongation, chromatin assembly and maintenance, and related regulatory mechanisms.

PrimPol (Primase/Polymerase), replicating enzyme – A mini review

2020 ◽  
Vol 2 (4) ◽  
pp. 89-92
Author(s):  
Muhammad Amir ◽  
Sabeera Afzal ◽  
Alia Ishaq
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Genetic Information ◽  
Nuclear Dna ◽  
De Novo ◽  
Dna Polymerases ◽  
Test Site ◽  
Mitochondrial Dna Replication ◽  
Dna Template ◽  
Preliminary Phase

Polymerases were revealed first in 1970s. Most important to the modest perception the enzyme responsible for nuclear DNA replication that was pol , for DNA repair pol and for mitochondrial DNA replication pol  DNA construction and renovation done by DNA polymerases, so directing both the constancy and discrepancy of genetic information. Replication of genome initiate with DNA template-dependent fusion of small primers of RNA. This preliminary phase in replication of DNA demarcated as de novo primer synthesis which is catalyzed by specified polymerases known as primases. Sixteen diverse DNA-synthesizing enzymes about human perspective are devoted to replication, reparation, mutilation lenience, and inconsistency of nuclear DNA. But in dissimilarity, merely one DNA polymerase has been called in mitochondria. It has been suggest that PrimPol is extremely acting the roles by re-priming DNA replication in mitochondria to permit an effective and appropriate way replication to be accomplished. Investigations from a numeral of test site have significantly amplified our appreciative of the role, recruitment and regulation of the enzyme during DNA replication. Though, we are simply just start to increase in value the versatile roles that play PrimPol in eukaryote.

Regulation of microRNAs in Inflammation-Associated Colorectal Cancer: A Mechanistic Approach

2020 ◽  
Vol 20 ◽  
Author(s):  
Sridhar Muthusami ◽  
Ilangovan Ramachandran ◽  
Sneha Krishnamoorthy ◽  
Yuvaraj Sambandam ◽  
Satish Ramalingam ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Molecular Mechanisms ◽  
Colorectal Carcinogenesis ◽  
Model Systems ◽  
Necrosis Factor Alpha ◽  
Multi Stage ◽  
Mechanistic Approach ◽  
Tnf Α ◽  
Factor Alpha

: The development of colorectal cancer (CRC) is a multi-stage process. The inflammation of the colon as in inflammatory bowel disease (IBD) such as ulcerative colitis (UC) or Crohn’s disease (CD) is often regarded as the initial trigger for the development of CRC. Many cytokines such as tumor necrosis factor alpha (TNF-α) and several interleukins (ILs) are known to exert proinflammatory actions, and inflammation initiates or promotes tumorigenesis of various cancers, including CRC through differential regulation of microRNAs (miRNAs/miRs). miRNAs can be oncogenic miRNAs (oncomiRs) or anti-oncomiRs/tumor suppressor miRNAs, and they play key roles during colorectal carcinogenesis. However, the functions and molecular mechanisms of regulation of miRNAs involved in inflammation-associated CRC are still anecdotal and largely unknown. Consolidating the published results and offering perspective solutions to circumvent CRC, the current review is focused on the role of miRNAs and their regulation in the development of CRC. We have also discussed the model systems adapted by researchers to delineate the role of miRNAs in inflammation-associated CRC.

Sign in / Sign up

Export Citation Format

Share Document