Expression levels of the human DNA repair protein metnase influence lentiviral genomic integration

Williamson, Elizabeth A.; Farrington, Jacqueline; Martinez, Leah; Ness, Scott A.; O'Rourke, John P.; Lee, Suk Hee; Nickoloff, Jac A.; Hromas, Robert

doi:10.1016/j.biochi.2008.05.010

Cited by 19 publications

(23 citation statements)

References 16 publications

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“…However, given that DNA end joining often requires processing of non-compatible ends additional factors are necessary for completion of NHEJ in a cell-free system (22, 28, 29). We previously reported that Metnase forms DSB foci with other repair factors and stimulates DSB repair and genomic integration of foreign DNA in vivo (32, 39, 44, 59). In this study, we showed that Metnase possesses a unique endonuclease activity that plays a positive role in the joining of non-compatible ends in cell-free system.…”

Section: Discussionmentioning

confidence: 99%

Biochemical Characterization of Metnase’s Endonuclease Activity and Its Role in NHEJ Repair

Beck¹,

Lee²,

Williamson

et al. 2011

Biochemistry

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Metnase (SETMAR) is a SET-transposase fusion protein that promotes non-homologous end joining (NHEJ) repair in humans. Although both SET and the transposase domains were necessary for its function in DSB repair, it is not clear what specific role Metnase plays in the NHEJ. In this study, we show that Metnase possesses a unique endonuclease activity that preferentially acts on ssDNA and ssDNA-overhang of a partial duplex DNA. Cell extracts lacking Metnase poorly supported DNA end joining, and addition of wt-Metnase to cell extracts lacking Metnase markedly stimulated DNA end joining, while a mutant (D483A) lacking endonuclease activity did not. Given that Metnase overexpression enhanced DNA end processing in vitro, our finding suggests a role for Metnase's endonuclease activity in promoting the joining of non-compatible ends.

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Section: Discussionmentioning

confidence: 99%

Biochemical Characterization of Metnase’s Endonuclease Activity and Its Role in NHEJ Repair

Beck¹,

Lee²,

Williamson

et al. 2011

Biochemistry

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“…Metnase levels were assessed using reverse-transcribed polymerase chain reaction (RT-PCR) and Western blotting as we described. 12,22 Each experiment using shRNA repressed Metnase was performed in at least 2 independent clones, with nearly identical results.…”

Section: Manipulating Metnase Levelsmentioning

confidence: 99%

Metnase mediates chromosome decatenation in acute leukemia cells

Wray

Williamson

Sheema

et al. 2009

Blood

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After DNA replication, sister chromatids must be untangled, or decatenated, before mitosis so that chromatids do not tear during anaphase. Topoisomerase II␣ (Topo II␣) is the major decatenating enzyme. Topo II␣ inhibitors prevent decatenation, causing cells to arrest during mitosis. Here we report that acute myeloid leukemia cells fail to arrest at the mitotic decatenation checkpoint, and their progression through this checkpoint is regulated by the DNA repair IntroductionDNA double-strand breaks (DSBs) can result from normal cellular events, such as recombination during immune receptor rearrangement, recovery of stalled replication forks, replication of nicked templates, or failed decatenation. 1 Such DSBs can result in translocations or deletions, and this genomic instability can lead to malignancy. Of the normal cell processes producing DSBs, the least well understood is chromosome decatenation. Sister chromatids become intertwined, or catenated, when chromosomes are replicated during DNA synthesis. When decatenation fails, chromatids can tear during anaphase, producing DSBs. Catenation status is actively monitored at 2 points in the cell cycle. One decatenation checkpoint blocks progression from G 2 to M 2 , and another blocks progression from metaphase to anaphase during mitosis. [2][3][4][5][6] These checkpoints are conserved in most organisms, including yeast. 7,8 Previously, it was reported that bladder and lung cancer cells lack decatenation checkpoints and proceed through mitosis even when decatenation is inhibited. 9,10 It is possible that this failure of arrest at the decatenation checkpoints could be a general feature of malignancy, including acute leukemia. The critical decatenating enzyme is Topoisomerase II␣ (Topo II␣). [2][3][4][5][6]11 Topo II␣ inhibitors can trigger decatenation checkpoint arrest in normal cells at either of the 2 decatenation checkpoints. Recently, we identified and characterized a novel DNA repair protein called Metnase (also SETMAR). Metnase has an amino terminal SET histone methylase domain and a carboxy terminal transposase/nuclease domain. We previously reported that Metnase promotes nonhomologous endjoining of DSBs and methylates histone 3 lysine 36. 12 Metnase appears to be localized to DSBs by interaction with Pso4, a poorly characterized DNA repair component. 13 Metnase may promote DSB repair by interacting with DNA ligase IV, the final component of the nonhomologous end-joining pathway. 14 Metnase is present only in primates and exhibits only partial transposase activity. 12,[14][15][16][17][18][19] We also found that Metnase has endonuclease activity specific for supercoiled DNA and improves Topo II␣-mediated decatenation in vitro and in vivo in noncancerous human cells. 16,20 In this study, we hypothesized that Metnase mediates decatenation in acute leukemia cells. If there is a failure of decatenation arrest in acute leukemia cells when Topo II␣ is inhibited, then perhaps Metnase mediated the continued progression of those cells through the decatenation checkpoi...

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“…Other cellular repair factors have been demonstrated to suppress viral infection, including XPB and XPD [86] of the nucleotide excision repair pathway, RAD52 [87], and Rad18 [88]. Metnase is a protein that promotes DSB repair by NHEJ [89] and has been suggested to influence lentivirus integration [90]. Defective repair pathways might indirectly affect virus integration by providing longer lasting breaks that are exploited by viral genomes.…”

Section: Dna Damage Signaling In Viral Infectionmentioning

confidence: 99%

Viral manipulation of DNA repair and cell cycle checkpoints

2009

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Recognition and repair of DNA damage is critical for maintaining genomic integrity and suppressing tumorigenesis. In eukaryotic cells, the sensing and repair of DNA damage are exquisitely coordinated with cell cycle progression and checkpoints, in order to prevent the propagation of damaged DNA. The carefully maintained cellular response to DNA damage is challenged by viruses, which produce a large amount of exogenous DNA during infection. Viruses also express proteins that perturb cellular DNA repair and cell cycle pathways, promoting tumorigenesis in their quest for cellular domination. This review presents an overview of strategies employed by viruses to manipulate DNA damage responses and cell cycle checkpoints as they commandeer the cell to maximize their own viral replication. Studies of viruses have identified key cellular regulators and revealed insights into molecular mechanisms governing DNA repair, cell cycle checkpoints, and transformation.

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Expression levels of the human DNA repair protein metnase influence lentiviral genomic integration

Cited by 19 publications

References 16 publications

Biochemical Characterization of Metnase’s Endonuclease Activity and Its Role in NHEJ Repair

Biochemical Characterization of Metnase’s Endonuclease Activity and Its Role in NHEJ Repair

Metnase mediates chromosome decatenation in acute leukemia cells

Viral manipulation of DNA repair and cell cycle checkpoints

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