Abstract
DNA ligase IV in a complex with XRCC4 is responsible for DNA end-joining in repair of DNA double-strand breaks (DSB) and V(D)J recombination. We found that non-histone chromosomal high mobility group (HMG) proteins 1 and 2 enhanced the ligation of linearized pUC119 DNA with DNA ligase IV from rat liver nuclear extract. Intra-molecular and inter-molecular ligations of cohesive-ended and blunt-ended DNA were markedly stimulated by HMG1 and 2. Recombinant HMG2-domain A, B, and (A + B) polypeptides were similarly, but non-identically, effective for the stimulation of DSB ligation reaction. Ligation of single-strand breaks (nicks) was only slightly activated by the HMG proteins. The DNA end-binding Ku protein singly or in combination with the catalytic component of DNA-dependent protein kinase (DNA-PK) as the DNA-PK holoenzyme was ineffective for the ligation of linearized pUC119 DNA. Although the stimulatory effect of HMG1 and 2 on ligation of DSB in vitro was not specific to DNA ligase IV, these results suggest that HMG1 and 2 are involved in the final ligation step in DNA end-joining processes of DSB repair and V(D)J recombination.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, Nuclear*
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Cell Nucleus / metabolism
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DNA Damage
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DNA Helicases*
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DNA Ligase ATP
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DNA Ligases / isolation & purification
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DNA Ligases / metabolism
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DNA Repair / drug effects*
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DNA Repair / physiology*
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DNA, Single-Stranded / metabolism
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DNA-Activated Protein Kinase
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DNA-Binding Proteins / metabolism
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DNA-Binding Proteins / pharmacology
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High Mobility Group Proteins / chemistry
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High Mobility Group Proteins / metabolism*
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High Mobility Group Proteins / pharmacology*
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Humans
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In Vitro Techniques
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Ku Autoantigen
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Liver / metabolism
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Nuclear Proteins / metabolism
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Nuclear Proteins / pharmacology
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Protein Serine-Threonine Kinases / metabolism
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Rats
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Recombinant Proteins / pharmacology
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Swine
Substances
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Antigens, Nuclear
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DNA, Single-Stranded
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DNA-Binding Proteins
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High Mobility Group Proteins
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LIG4 protein, human
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Lig1 protein, rat
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Nuclear Proteins
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Recombinant Proteins
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DNA-Activated Protein Kinase
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PRKDC protein, human
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Protein Serine-Threonine Kinases
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DNA Helicases
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XRCC5 protein, human
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Xrcc6 protein, human
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Xrcc6 protein, rat
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Ku Autoantigen
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DNA Ligases
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DNA Ligase ATP