27,491 results match your criteria mechanisms recombination


Reinstatement of Item-Specific Contextual Details During Retrieval Supports Recombination-Related False Memories.

Neuroimage 2021 Apr 6:118033. Epub 2021 Apr 6.

Department of Psychology and Center for Brain Science, Harvard University.

Flexible retrieval mechanisms that allow us to infer relationships across events may also lead to memory errors or distortion when details of one event are misattributed to the related event. Here, we tested how making successful inferences alters representation of overlapping events, leading to false memories. Participants encoded overlapping associations ('AB' and 'BC'), each of which was superimposed on different indoor and outdoor scenes that were pre-exposed prior to associative learning. Read More

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A study of transposable element-associated structural variations (TASVs) using a de novo-assembled Korean genome.

Exp Mol Med 2021 Apr 8. Epub 2021 Apr 8.

Department of Biological Sciences, Pusan National University, Busan, 46283, Republic of Korea.

Advances in next-generation sequencing (NGS) technology have made personal genome sequencing possible, and indeed, many individual human genomes have now been sequenced. Comparisons of these individual genomes have revealed substantial genomic differences between human populations as well as between individuals from closely related ethnic groups. Transposable elements (TEs) are known to be one of the major sources of these variations and act through various mechanisms, including de novo insertion, insertion-mediated deletion, and TE-TE recombination-mediated deletion. Read More

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Smc5/6 functions with Sgs1-Top3-Rmi1 to complete chromosome replication at natural pause sites.

Nat Commun 2021 04 8;12(1):2111. Epub 2021 Apr 8.

IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy.

Smc5/6 is essential for genome structural integrity by yet unknown mechanisms. Here we find that Smc5/6 co-localizes with the DNA crossed-strand processing complex Sgs1-Top3-Rmi1 (STR) at genomic regions known as natural pausing sites (NPSs) where it facilitates Top3 retention. Individual depletions of STR subunits and Smc5/6 cause similar accumulation of joint molecules (JMs) composed of reversed forks, double Holliday Junctions and hemicatenanes, indicative of Smc5/6 regulating Sgs1 and Top3 DNA processing activities. Read More

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The uncharacterized SANT and BTB domain-containing protein SANBR inhibits class switch recombination.

J Biol Chem 2021 Apr 5:100625. Epub 2021 Apr 5.

Department of Biology, The Graduate Center and The City College of New York, New York, NY, 10031, USA. Electronic address:

Class switch recombination (CSR) is the process by which B cells switch production from IgM/IgD to other immunoglobulin isotypes, enabling them to mount an effective immune response against pathogens. Timely resolution of CSR prevents damage due to an uncontrolled and prolonged immune response. While many positive regulators of CSR have been described, negative regulators of CSR are relatively unknown. Read More

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Emergence of aac(6')-Ie-aph(2'')-Ia-positive enterococci with non-high-level gentamicin resistance mediated by IS1216V: adaptation to decreased aminoglycoside usage in Taiwan.

J Antimicrob Chemother 2021 Apr 2. Epub 2021 Apr 2.

Department of Microbiology and Immunology, College of Medicine, Kaohsiung Medical University, Taiwan.

Objectives: To explore the mechanisms mediating the different levels of gentamicin resistance in enterococci.

Methods: Susceptibility testing with gentamicin and PCR of resistance determinants were performed in 149 enterococcal isolates. Genetic relatedness was characterized by MLST and PFGE analysis. Read More

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Replicated chromatin curtails 53BP1 recruitment in BRCA1-proficient and BRCA1-deficient cells.

Life Sci Alliance 2021 Jun 2;4(6). Epub 2021 Apr 2.

Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland

DNA double-strand breaks can be repaired by non-homologous end-joining or homologous recombination. Which pathway is used depends on the balance between the tumor suppressors 53BP1 and BRCA1 and on the availability of an undamaged template DNA for homology-directed repair. How cells switch from a 53BP1-dominated to a BRCA1-governed homologous recombination response as they progress through the cell cycle is incompletely understood. Read More

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Virus Evolution and Neutralization Sensitivity in an HIV-1 Subtype B' Infected Plasma Donor with Broadly Neutralizing Activity.

Vaccines (Basel) 2021 Mar 25;9(4). Epub 2021 Mar 25.

State Key Laboratory of Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.

We sought to analyze the evolutionary characteristics and neutralization sensitivity of viruses in a human immunodeficiency virus type 1 (HIV-1) subtype B' infected plasma donor with broadly neutralizing activity, which may provide information for new broadly neutralizing antibodies (bNAbs) isolation and immunogen design. A total of 83 full-length envelope genes were obtained by single-genome amplification (SGA) from the patient's plasma at three consecutive time points (2005, 2006, and 2008) spanning four years. In addition, 28 Env-pseudotyped viruses were constructed and their neutralization sensitivity to autologous plasma and several representative bNAbs were measured. Read More

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Influence of Colloidal Au on the Growth of ZnO Nanostructures.

Nanomaterials (Basel) 2021 Mar 29;11(4). Epub 2021 Mar 29.

ENFOCAT-IN2UB, Universitat de Barcelona (UB), C/Martí i Franquès 1, 08028 Barcelona, Catalunya, Spain.

Vapor-liquid-solid processes allow growing high-quality nanowires from a catalyst. An alternative to the conventional use of catalyst thin films, colloidal nanoparticles offer advantages not only in terms of cost, but also in terms of controlling the location, size, density, and morphology of the grown nanowires. In this work, we report on the influence of different parameters of a colloidal Au nanoparticle suspension on the catalyst-assisted growth of ZnO nanostructures by a vapor-transport method. Read More

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Special Issue: DNA Helicases: Mechanisms, Biological Pathways, and Disease Relevance.

Authors:
Robert M Brosh

Genes (Basel) 2021 Mar 1;12(3). Epub 2021 Mar 1.

Section on DNA Helicases, Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA.

DNA helicases have emerged as a prominent class of nucleic acid-metabolizing enzymes that play important roles in genome maintenance and cellular homeostasis [... Read More

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Targeting in Cancer: Promising Therapeutic Strategies.

Cancers (Basel) 2021 Mar 10;13(6). Epub 2021 Mar 10.

Department of Genomic Medicine, Division of Cancer Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.

The Kirsten rat sarcoma viral oncogene homolog () is mutated in approximately 25% of all human cancers and is known to be a major player promoting and maintaining tumorigenesis through the RAS/MAPK pathway. Over the years, a large number of studies have identified strategies at different regulatory levels to tackle this 'difficult-to-target' oncoprotein. Yet, the most ideal strategy to overcome and its downstream effects has yet to be uncovered. Read More

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Palindromes in DNA-A Risk for Genome Stability and Implications in Cancer.

Int J Mol Sci 2021 Mar 11;22(6). Epub 2021 Mar 11.

Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.

A palindrome in DNA consists of two closely spaced or adjacent inverted repeats. Certain palindromes have important biological functions as parts of various cis-acting elements and protein binding sites. However, many palindromes are known as fragile sites in the genome, sites prone to chromosome breakage which can lead to various genetic rearrangements or even cell death. Read More

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Critical roles of Rad54 in tolerance to apigenin-induced Top1-mediated DNA damage.

Exp Ther Med 2021 May 18;21(5):505. Epub 2021 Mar 18.

Department of Pharmacology, Key Laboratory of Drug-Targeting and Drug Delivery Systems of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041, P.R. China.

Apigenin (APG), a flavone sub-class of flavonoids, possesses a diverse range of biological activities, including anti-cancer and anti-inflammatory effects. Previous studies identified the genotoxicity of APG in certain cancer cells, which may be associated with its anticancer effect. However, the DNA damage repair mechanism induced by APG has remained elusive. Read More

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Targeting acute myeloid leukemia dependency on VCP-mediated DNA repair through a selective second-generation small-molecule inhibitor.

Sci Transl Med 2021 Mar;13(587)

Université de Paris, INSERM U944 and CNRS UMR 7212, Institut de Recherche Saint Louis, Hôpital Saint Louis, APHP, 75010 Paris, France.

The development and survival of cancer cells require adaptive mechanisms to stress. Such adaptations can confer intrinsic vulnerabilities, enabling the selective targeting of cancer cells. Through a pooled in vivo short hairpin RNA (shRNA) screen, we identified the adenosine triphosphatase associated with diverse cellular activities (AAA-ATPase) valosin-containing protein (VCP) as a top stress-related vulnerability in acute myeloid leukemia (AML). Read More

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LRRK2 inhibition potentiates PARP inhibitor cytotoxicity through inhibiting homologous recombination-mediated DNA double strand break repair.

Clin Transl Med 2021 Mar;11(3):e341

Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota.

PARP inhibitors induce DNA lesions, the repair of which are highly dependent on homologous recombination (HR), and preferentially kill HR- deficient cancers. However, cancer cells have developed several mechanisms to transform HR and confer drug resistance to PARP inhibition. Therefore, there is a great clinical interest in exploring new therapies that induce HR deficiency (HRD), thereby sensitizing cancer cells to PARP inhibitors. Read More

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Plant sex chromosomes defy evolutionary models of expanding recombination suppression and genetic degeneration.

Nat Plants 2021 Mar 29. Epub 2021 Mar 29.

Thünen Institute of Forest Genetics, Grosshansdorf, Germany.

Hundreds of land plant lineages have independently evolved separate sexes in either gametophytes (dioicy) or sporophytes (dioecy), but 43% of all dioecious angiosperms are found in just 34 entirely dioecious clades, suggesting that their mode of sex determination evolved a long time ago. Here, we review recent insights on the molecular mechanisms that underlie the evolutionary change from individuals that each produce male and female gametes to individuals specializing in the production of just one type of gamete. The canonical model of sex chromosome evolution in plants predicts that two sex-determining genes will become linked in a sex-determining region (SDR), followed by expanding recombination suppression, chromosome differentiation and, ultimately, degeneration. Read More

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Modeling DNA trapping of anticancer therapeutic targets using missense mutations identifies dominant synthetic lethal interactions.

Proc Natl Acad Sci U S A 2021 Apr;118(14)

Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada

Genetic screens can identify synthetic lethal (SL) interactions and uncover potential anticancer therapeutic targets. However, most SL screens have utilized knockout or knockdown approaches that do not accurately mimic chemical inhibition of a target protein. Here, we test whether missense mutations can be utilized as a model for a type of protein inhibition that creates a dominant gain-of-function cytotoxicity. Read More

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Mismatch detection in homologous strand exchange amplified by hydrophobic effects.

Biopolymers 2021 Mar 29:e23426. Epub 2021 Mar 29.

Department of Chemistry & Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.

In contrast to DNA replication and transcription where nucleotides are added and matched one by one, homologous recombination by DNA strand exchange tests whole sequences for complementarity, which requires elimination of mismatched yet thermodynamically stable intermediates. To understand the remarkable sequence specificity of homologous recombination, we have studied strand exchange between a 20-mer duplex containing one single mismatch (placed at varied positions) with the matching single strand in presence of poly(ethylene glycol) representing a semi-hydrophobic environment. A FRET-based assay shows that rates and yields of strand exchange from mismatched to matched strands rapidly increase with semi-hydrophobic co-solute concentration, contrasting previously observed general strand exchange accelerating effect of ethyl glycol ethers. Read More

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Activators of SIRT1 in the kidney and protective effects of SIRT1 during acute kidney injury (AKI) (effect of SIRT1 activators on acute kidney injury).

Clin Exp Nephrol 2021 Mar 29. Epub 2021 Mar 29.

Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.

Acute kidney injury (AKI) is a complex disorder and a clinical condition characterized by acute reduction in renal function. If AKI is not treated, it can lead to chronic kidney disease, which is associated with a high risk of death. SIRT1 (silent information regulator 1) is an NAD-dependent deacetylase. Read More

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Functions of BLM Helicase in Cells: Is It Acting Like a Double-Edged Sword?

Front Genet 2021 12;12:634789. Epub 2021 Mar 12.

Signal Transduction Laboratory-2, National Institute of Immunology, New Delhi, India.

DNA damage repair response is an important biological process involved in maintaining the fidelity of the genome in eukaryotes and prokaryotes. Several proteins that play a key role in this process have been identified. Alterations in these key proteins have been linked to different diseases including cancer. Read More

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Chromosome number is key to longevity of polyploid lineages.

New Phytol 2021 Mar 26. Epub 2021 Mar 26.

Plant Genome Mapping Laboratory, University of Georgia, Athens, GA, 30602, USA.

Polyploidy is ubiquitous and often recursive in plant lineages, most frequently resulting in extinction but occasionally associated with great evolutionary success. However, instead of chromosome numbers exponentially increasing due to recurrent polyploidy, most Angiosperm species have fewer than 14 chromosome pairs. Following genome duplication, diploidization can render one copy of essential genes non-functional without fitness cost. Read More

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The role of novel poly (ADP-ribose) inhibitors in the treatment of locally advanced and metastatic Her-2/neu negative breast cancer with inherited germline BRCA1/2 mutations. A review of the literature.

J Med Life 2021 Jan-Mar;14(1):17-20

Department of Obstetrics and Gynecology, Ovidius University, Constanta, Romania.

The use of the PARP inhibitors (PARPi) in the treatment of breast cancer (BC) with germine mutations has evolved over the years, and further research has been done in order to broaden the horizon of this treatment strategy. Therefore the aim of this paper is to review the efficiency of PARPi in the treatment of BRCA 1/2-mutated locally advanced and metastatic Her-2/net negative BC mentioning their side effects, mechanism of resistance and future directions. Inhibition of PARP transforms single-strand breaks into double-strand breaks (DBS), the accumulation of the latter causing cell death (cell apoptosis). Read More

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The Role of Chromatid Interference in Determining Meiotic Crossover Patterns.

Front Plant Sci 2021 9;12:656691. Epub 2021 Mar 9.

Laboratory for Plant Genetics and Crop Improvement, Division of Crop Biotechnics, Department of Biosystems, Katholieke Universiteit Leuven, Leuven, Belgium.

Plants, like all sexually reproducing organisms, create genetic variability by reshuffling parental alleles during meiosis. Patterns of genetic variation in the resulting gametes are determined by the independent assortment of chromosomes in meiosis I and by the number and positioning of crossover (CO) events during meiotic recombination. On the chromosome level, spatial distribution of CO events is biased by multiple regulatory mechanisms, such as CO assurance, interference and homeostasis. Read More

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Distinct Carrier Transport Properties Across Horizontally vs Vertically Oriented Heterostructures of 2D/3D Perovskites.

J Am Chem Soc 2021 Apr 25;143(13):4969-4978. Epub 2021 Mar 25.

Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.

Two-dimensional-on-three-dimensional (2D/3D) halide perovskite heterostructures have been extensively utilized in optoelectronic devices. However, the labile nature of halide perovskites makes it difficult to form such heterostructures with well-defined compositions, orientations, and interfaces, which inhibits understanding of the carrier transfer properties across these heterostructures. Here, we report solution growth of both horizontally and vertically aligned 2D perovskite (PEA)PbBr (PEA = phenylethylammonium) microplates onto 3D CsPbBr single crystal thin films, with well-defined heterojunctions. Read More

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The effects of GC-biased gene conversion on patterns of genetic diversity among and across butterfly genomes.

Genome Biol Evol 2021 Mar 24. Epub 2021 Mar 24.

Evolutionary Biology Program, Department of Ecology and Genetics (IEG), Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden.

Recombination reshuffles the alleles of a population through crossover and gene conversion. These mechanisms have considerable consequences on the evolution and maintenance of genetic diversity. Crossover, for example, can increase genetic diversity by breaking the linkage between selected and nearby neutral variants. Read More

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The evolutionary history of ACE2 usage within the coronavirus subgenus .

Virus Evol 2021 Jan 5;7(1):veab007. Epub 2021 Feb 5.

Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.

Severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and SARS-CoV-2 are not phylogenetically closely related; however, both use the angiotensin-converting enzyme 2 (ACE2) receptor in humans for cell entry. This is not a universal sarbecovirus trait; for example, many known sarbecoviruses related to SARS-CoV-1 have two deletions in the receptor binding domain of the spike protein that render them incapable of using human ACE2. Here, we report three sequences of a novel sarbecovirus from Rwanda and Uganda that are phylogenetically intermediate to SARS-CoV-1 and SARS-CoV-2 and demonstrate via in vitro studies that they are also unable to utilize human ACE2. Read More

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January 2021

Confined placental mosaicism involving multiple de novo copy number variants associated with fetal growth restriction: A case report.

Am J Med Genet A 2021 Mar 22. Epub 2021 Mar 22.

BC Children's Hospital Research Institute, Vancouver, Canada.

The presence of multiple large (>1 Mb) copy number variants (CNVs) in non-malignant tissue is rare in human genetics. We present a liveborn male with a birth weight below the first percentile associated with placental mosaicism involving eight 2.4-3. Read More

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Natural Medicines for the Treatment of Epilepsy: Bioactive Components, Pharmacology and Mechanism.

Front Pharmacol 2021 4;12:604040. Epub 2021 Mar 4.

College of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China.

Epilepsy is a chronic disease that can cause temporary brain dysfunction as a result of sudden abnormal discharge of the brain neurons. The seizure mechanism of epilepsy is closely related to the neurotransmitter imbalance, synaptic recombination, and glial cell proliferation. In addition, epileptic seizures can lead to mitochondrial damage, oxidative stress, and the disorder of sugar degradation. Read More

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Plasmodium Ape1 is a multifunctional enzyme in mitochondrial base excision repair and is required for efficient transition from liver to blood stage infection.

DNA Repair (Amst) 2021 May 14;101:103098. Epub 2021 Mar 14.

Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India. Electronic address:

The malaria parasite has a single mitochondrion which carries multiple tandem repeats of its 6 kb genome encoding three proteins of the electron transport chain. There is little information about DNA repair mechanisms for mitochondrial genome maintenance in Plasmodium spp. Of the two AP-endonucleases of the BER pathway encoded in the parasite nuclear genome, the EndoIV homolog PfApn1 has been identified as a mitochondrial protein with restricted functions. Read More

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Copy number-dependent DNA methylation of the Pyricularia oryzae MAGGY retrotransposon is triggered by DNA damage.

Commun Biol 2021 Mar 19;4(1):351. Epub 2021 Mar 19.

Laboratory of Cell Function and Structure, Graduate School of Agricultural Science, Kobe University, Nada Kobe, Japan.

Transposable elements are common targets for transcriptional and post-transcriptional gene silencing in eukaryotic genomes. However, the molecular mechanisms responsible for sensing such repeated sequences in the genome remain largely unknown. Here, we show that machinery of homologous recombination (HR) and RNA silencing play cooperative roles in copy number-dependent de novo DNA methylation of the retrotransposon MAGGY in the fungus Pyricularia oryzae. Read More

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Recombinational repair in the absence of holliday junction resolvases in E. coli.

Mutat Res 2021 Feb 13;822:111740. Epub 2021 Feb 13.

Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada. Electronic address:

Cells possess two major DNA damage tolerance pathways that allow them to duplicate their genomes despite the presence of replication blocking lesions: translesion synthesis (TLS) and daughter strand gap repair (DSGR). The TLS pathway involves specialized DNA polymerases that are able to synthesize past DNA lesions while DSGR relies on Recombinational Repair (RR). At least two mechanisms are associated with RR: Homologous Recombination (HR) and RecA Mediated Excision Repair (RAMER). Read More

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February 2021