Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.5.1.1 (DNA ligase)
 2,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The paradigm for repair of oxidized base lesions in genomes via the base excision repair (BER) pathway is based on studies in Escherichia coli, in which AP endonuclease (APE) removes all 3' blocking groups (including 3' phosphate) generated by DNA glycosylase/AP lyases after base excision. The recently discovered mammalian DNA glycosylase/AP lyases, NEIL1 and NEIL2, unlike the previously characterized OGG1 and NTH1, generate DNA strand breaks with 3' phosphate termini. Here we show that in mammalian cells, removal of the 3' phosphate is dependent on polynucleotide kinase (PNK), and not APE. NEIL1 stably interacts with other BER proteins, DNA polymerase beta (pol beta) and DNA ligase IIIalpha. The complex of NEIL1, pol beta, and DNA ligase IIIalpha together with PNK suggests coordination of NEIL1-initiated repair. That NEIL1/PNK could also repair the products of other DNA glycosylases suggests a broad role for this APE-independent BER pathway in mammals.
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PMID:AP endonuclease-independent DNA base excision repair in human cells. 1526 Sep 72

DNA glycosylases/AP lyases initiate repair of oxidized bases in the genomes of all organisms by excising these lesions and then cleaving the DNA strand at the resulting abasic (AP) sites and generate 3' phospho alpha,beta-unsaturated aldehyde (3' PUA) or 3' phosphate (3' P) terminus. In Escherichia coli, the AP-endonucleases (APEs) hydrolyze both 3' blocking groups (3' PUA and 3' P) to generate the 3'-OH termini needed for repair synthesis. In mammalian cells, the previously characterized DNA glycosylases, NTH1 and OGG1, produce 3' PUA, which is removed by the only AP-endonuclease, APE1. However, APE1 is barely active in removing 3' phosphate generated by the recently discovered mammalian DNA glycosylases NEIL1 and NEIL2. We showed earlier that the 3' phosphate generated by NEIL1 is efficiently removed by polynucleotide kinase (PNK) and not APE1. Here we show that the NEIL2-initiated repair of 5-hydroxyuracil (5-OHU) similarly requires PNK. We have also observed stable interaction between NEIL2 and other BER proteins DNA polymerase beta (Pol beta), DNA ligase IIIalpha (Lig IIIalpha) and XRCC1. In spite of their limited sequence homology, NEIL1 and NEIL2 interact with the same domains of Pol beta and Lig IIIalpha. Surprisingly, while the catalytically dispensable C-terminal region of NEIL1 is the common interacting domain, the essential N-terminal segment of NEIL2 is involved in analogous interaction. The BER proteins including NEIL2, PNK, Pol beta, Lig IIIalpha and XRCC1 (but not APE1) could be isolated as a complex from human cells, competent for repair of 5-OHU in plasmid DNA.
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PMID:NEIL2-initiated, APE-independent repair of oxidized bases in DNA: Evidence for a repair complex in human cells. 1698 18

Background: Nei endonuclease VIII-like 2 (NEIL2) is a gene encoding DNA repair enzyme, which is involved in the base excision repair (BER) pathway in mammalian cells. Cisplatin is a common cytotoxic anti-tumor agent in clinic by destroying normal structure of DNA and inducing cell apoptosis. However, how NEIL2 affects the sensitivity of NSCLC to cisplatin is still unclear. Methods: The clinical data from 206 patients diagnosed pathologically were collected. The DNA sequencing of NEIL2 gene 3'UTR and the PFS curve of NSCLC patients receiving cisplatin-based chemotherapy were performed. Western blot analysis and immunohistochemistry were used to detect NEIL2 protein expression. Human NSCLC cell lines A549 and H1299 were cultured and evaluated for cell viability. RT-PCR was performed for quantitative detection of miR-548a. 3'UTR reporter plasmid was constructed and luciferase reporter assay was used to verify the target gene regulated by miR-548a. Results: In this study, we found that the Neil2 gene had the polymorphism (T/C) in rs8191670 and it is associated with the PFS of advanced NSCLC patients. MiR-548a targets NEIL2 3'UTR to suppress its expression. Upregulation of NEIL2 expression or downregulation of miR-548a could reduce the sensitivity of NSCLC cells to cisplatin. Conclusion: Our results demonstrated that NEIL2 gene rs8191670 polymorphism affects the PFS of advanced NSCLC patients, and the underlying molecular mechanisms may be that miR-548a can regulate NEIL2 expression by binding to its 3'UTR seed region containing rs8191670.
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PMID:Nei Endonuclease VIII-like 2 Gene rs8191670 Polymorphism affects the Sensitivity of Non-small Cell Lung Cancer to Cisplatin by binding with MiR-548a. 3262 27