Polymerase μ in non-homologous DNA end joining: importance of the order of arrival at a double-strand break in a purified system. 2020

Bailin Zhao, and Go Watanabe, and Michael R Lieber
Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA.

During non-homologous DNA end joining (NHEJ), bringing two broken dsDNA ends into proximity is an essential prerequisite for ligation by XRCC4:Ligase IV (X4L4). This physical juxtaposition of DNA ends is called NHEJ synapsis. In addition to the key NHEJ synapsis proteins, Ku, X4L4, and XLF, it has been suggested that DNA polymerase mu (pol μ) may also align two dsDNA ends into close proximity for synthesis. Here, we directly observe the NHEJ synapsis by pol μ using a single molecule FRET (smFRET) assay where we can measure the duration of the synapsis. The results show that pol μ alone can mediate efficient NHEJ synapsis of 3' overhangs that have at least 1 nt microhomology. The abundant Ku protein in cells limits the accessibility of pol μ to DNA ends with overhangs. But X4L4 can largely reverse the Ku inhibition, perhaps by pushing the Ku inward to expose the overhang for NHEJ synapsis. Based on these studies, the mechanistic flexibility known to exist at other steps of NHEJ is now also apparent for the NHEJ synapsis step.

UI MeSH Term Description Entries
D004247 DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004259 DNA-Directed DNA Polymerase DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair. DNA Polymerase,DNA Polymerases,DNA-Dependent DNA Polymerases,DNA Polymerase N3,DNA Dependent DNA Polymerases,DNA Directed DNA Polymerase,DNA Polymerase, DNA-Directed,DNA Polymerases, DNA-Dependent,Polymerase N3, DNA,Polymerase, DNA,Polymerase, DNA-Directed DNA,Polymerases, DNA,Polymerases, DNA-Dependent DNA
D004268 DNA-Binding Proteins Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases. DNA Helix Destabilizing Proteins,DNA-Binding Protein,Single-Stranded DNA Binding Proteins,DNA Binding Protein,DNA Single-Stranded Binding Protein,SS DNA BP,Single-Stranded DNA-Binding Protein,Binding Protein, DNA,DNA Binding Proteins,DNA Single Stranded Binding Protein,DNA-Binding Protein, Single-Stranded,Protein, DNA-Binding,Single Stranded DNA Binding Protein,Single Stranded DNA Binding Proteins
D000072200 Ku Autoantigen An ATP-dependent DNA HELICASE that preferentially binds SINGLE-STRANDED DNA. It is a heterodimer consisting of an 80 kDa subunit (XRCC5) and 70 kDa subunit (XRCC6) that functions with DNA LIGASE IV in the repair of DOUBLE-STRANDED DNA BREAKS and V(D)J RECOMBINATION. G22P1 Antigen,Ku Antigen,Ku Autoantigen, 70 kDa,Ku Autoantigen, 80 kDa,Ku Heterodimer,Ku Protein,Ku70 Antigen,Ku80 Antigen,X-ray Repair Cross-Complementing Protein 5,X-ray Repair Cross-Complementing Protein 6,XRCC5 Protein,XRCC6 Protein,Antigen, G22P1,Antigen, Ku,Antigen, Ku70,Antigen, Ku80,Autoantigen, Ku,Heterodimer, Ku,X ray Repair Cross Complementing Protein 5,X ray Repair Cross Complementing Protein 6
D000072481 DNA Ligase ATP ATP-dependent cellular enzyme which catalyzes DNA replication, repair and recombination through formation of internucleotide ester bonds between phosphate and deoxyribose moieties. Vertebrate cells encode three well-characterized DNA ligases, DNA ligase I, III and IV, all of which are related in structure and sequence. DNA ligases either require ATP or NAD. However, archaebacterial, viral, and some eubacterial DNA ligases are ATP-dependent. ATP-Dependent DNA Ligase,DNA Ligase I,DNA Ligase II,DNA Ligase III,DNA Ligase IIIalpha,DNA Ligase IV,DNA Ligases, ATP-Dependent,LIGIIIalpha Protein,Polydeoxyribonucleotide Synthase ATP,ATP Dependent DNA Ligase,ATP, DNA Ligase,ATP, Polydeoxyribonucleotide Synthase,ATP-Dependent DNA Ligases,DNA Ligase, ATP-Dependent,DNA Ligases, ATP Dependent,IIIalpha, DNA Ligase,Ligase ATP, DNA,Ligase I, DNA,Ligase II, DNA,Ligase III, DNA,Ligase IIIalpha, DNA,Ligase IV, DNA,Ligase, ATP-Dependent DNA,Ligases, ATP-Dependent DNA,Synthase ATP, Polydeoxyribonucleotide
D000072760 Single Molecule Imaging High resolution imaging techniques that allow visualization of individual molecules of proteins, lipids, or nucleic acids within cells or tissues. Single Molecule Analysis,Single Molecule Tracking,Single Particle Analysis,Single Particle Imaging,Single Particle Microscopy,Single Particle Spectroscopy,Single Particle Tracking,Single Molecule Microscopy,Single Molecule Spectroscopy,Analyses, Single Particle,Analysis, Single Molecule,Analysis, Single Particle,Imaging, Single Molecule,Imaging, Single Particle,Microscopies, Single Particle,Microscopy, Single Molecule,Microscopy, Single Particle,Particle Tracking, Single,Single Molecule Analyses,Single Particle Analyses,Single Particle Microscopies,Single Particle Spectroscopies,Single Particle Trackings,Spectroscopy, Single Molecule,Spectroscopy, Single Particle,Tracking, Single Molecule,Tracking, Single Particle
D012689 Sequence Homology, Nucleic Acid The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function. Base Sequence Homology,Homologous Sequences, Nucleic Acid,Homologs, Nucleic Acid Sequence,Homology, Base Sequence,Homology, Nucleic Acid Sequence,Nucleic Acid Sequence Homologs,Nucleic Acid Sequence Homology,Sequence Homology, Base,Base Sequence Homologies,Homologies, Base Sequence,Sequence Homologies, Base
D053903 DNA Breaks, Double-Stranded Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently. Double-Stranded DNA Breaks,Double-Strand DNA Breaks,Double-Stranded DNA Break,Break, Double-Strand DNA,Break, Double-Stranded DNA,Breaks, Double-Strand DNA,Breaks, Double-Stranded DNA,DNA Break, Double-Strand,DNA Break, Double-Stranded,DNA Breaks, Double Stranded,DNA Breaks, Double-Strand,Double Strand DNA Breaks,Double Stranded DNA Break,Double Stranded DNA Breaks,Double-Strand DNA Break
D059766 DNA End-Joining Repair The repair of DOUBLE-STRAND DNA BREAKS by rejoining the broken ends of DNA to each other directly. Non-Homologous DNA End-Joining,End-Joining DNA Repair,MMEJ DNA Repair,Microhomology-Mediated End Joining Repair,NHEJ DNA Repair,Nonhomologous DNA End-Joining,DNA End Joining Repair,DNA End-Joining, Non-Homologous,DNA End-Joining, Nonhomologous,DNA Repair, End-Joining,DNA Repair, MMEJ,DNA Repair, NHEJ,End Joining DNA Repair,End-Joining Repair, DNA,End-Joining, Non-Homologous DNA,Microhomology Mediated End Joining Repair,Non Homologous DNA End Joining,Nonhomologous DNA End Joining,Repair, DNA End-Joining,Repair, End-Joining DNA,Repair, MMEJ DNA,Repair, NHEJ DNA
D031541 Fluorescence Resonance Energy Transfer A type of FLUORESCENCE SPECTROSCOPY using two FLUORESCENT DYES with overlapping emission and absorption spectra, which is used to indicate proximity of labeled molecules. This technique is useful for studying interactions of molecules and PROTEIN FOLDING. Forster Resonance Energy Transfer

Related Publications

Bailin Zhao, and Go Watanabe, and Michael R Lieber
June 2013, Translational cancer research,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
June 2005, DNA repair,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
October 2023, Nucleic acids research,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
August 2017, Nature reviews. Molecular cell biology,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
June 2018, Scientific reports,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
July 2014, Mutation research. Genetic toxicology and environmental mutagenesis,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
September 2006, DNA repair,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
April 2020, Current opinion in structural biology,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
September 1999, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme,
Bailin Zhao, and Go Watanabe, and Michael R Lieber
January 2013, The EMBO journal,
Copied contents to your clipboard!