In yeast, DNA breaks are usually repaired by homologous recombination (HR). An early step for HR pathways is formation of a heteroduplex, in which a single-strand from the broken DNA molecule pairs with a strand derived from an intact DNA molecule. If the two strands of DNA are not identical, there will be mismatches within the heteroduplex DNA (hetDNA). In wild-type strains, these mismatches are repaired by the mismatch repair (MMR) system, producing a gene conversion event. In strains lacking MMR, the mismatches persist. Most previous studies involving hetDNA formed during mitotic recombination were restricted to one locus. Below, we present a global mapping of hetDNA formed in the MMR-defective strain. We find that many recombination events are associated with repair of double-stranded DNA gaps and/or involve Mlh1-independent mismatch repair. Many of our events are not explicable by the simplest form of the double-strand break repair model of recombination.
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http://dx.doi.org/10.7554/eLife.28069 | DOI Listing |
Int J Mol Sci
November 2024
Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia.
The mechanism of transcription proceeds through the formation of R-loop structures containing a DNA-RNA heteroduplex and a single-stranded DNA segment that should be placed inside the elongation complex; therefore, these nucleic acid segments are limited in length. The attachment of each nucleotide to the 3' end of an RNA strand requires a repeating cycle of incoming nucleoside triphosphate binding, catalysis, and enzyme translocation. Within these steps of transcription elongation, RNA polymerase sequentially goes through several states and is post-translocated, catalytic, and pre-translocated.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India. Electronic address:
Chembiochem
November 2024
Department of Chemistry, University of Turku, 20500, Turku, Finland.
Molecular Spherical Nucleic Acids (MSNAs) are atomically uniform dendritic nanostructures and potential delivery vehicles for oligonucleotides. The radial formulation combined with covalent conjugation may hide the oligonucleotide content and simultaneously enhance the role of appropriate conjugate groups on the outer sphere. The conjugate halo may be modulated to affect the delivery properties of the MSNAs.
View Article and Find Full Text PDFMikrochim Acta
October 2024
Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
A unique approach is introduced for constructing gold nanocrystals (AuNCs) with RNA motif-directed morphologies in a sequence-independent manner and its applications in the clinical area are described. By using this method, a label-free LSPR-based detection method for the SOX2OT transcript, long non-coding RNAs (lncRNAs), which is a prognostic indicator of poor survival in lung cancer patients is presented. For the first time, we examined how the structural changes of RNA after the heteroduplex formation with a specific DNA probe can change the morphology and LSPR band of AuNCs.
View Article and Find Full Text PDFOrg Biomol Chem
October 2024
Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA.
Development of robust oligonucleotide-based probe technologies, capable of recognizing specific regions of double-stranded DNA (dsDNA) targets, continues to attract considerable attention due to the promise of tools for modulation of gene expression, diagnostic agents, and new modalities against genetic diseases. Our laboratory pursues the development of various strand-invading probes. These include Invader probes, , double-stranded oligonucleotide probes with one or more +1 interstrand zipper arrangements of intercalator-functionalized nucleotides like 2'--(pyren-1-yl)methyl-RNA monomers, and chimeric Invader/γPNA probes, , heteroduplex probes between individual Invader strands and complementary γPNA strands.
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