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NEIL1 and other BER proteins respond and bind to psoralen-induced DNA interstrand crosslinks and additional types of laser induced DNA damage.

Wednesday, November 06, 2013 — Poster Session I

4:00 p.m. – 6:00 p.m.

FAES Academic Center (Upper-Level Terrace)




  • DR McNeill
  • M Paramasivam
  • J Baldwin
  • J Huang
  • VN Vyjayanti
  • MM Seidman
  • DM Wilson III


Recent evidence suggests a role for base excision repair (BER) proteins in the response to DNA interstrand crosslinks (ICLs). Employing fluorescently-tagged fusion proteins and laser microirradiation coupled with confocal microscopy, we observed that NEIL1, accumulates at sites of oxidative DNA damage, as well as trioxsalen (psoralen)-induced DNA ICLs. Recruitment to the oxidative DNA lesions was abrogated by anti-oxidants, but did not alter the accumulation of NEIL1 at sites of ICLs, suggesting distinct recognition mechanisms. Recruitment of the NEIL1 population variants, G83D, C136R and E181K, to oxidative DNA damage and psoralen-induced ICLs was differentially affected by the mutation. Knockdown of NEIL1 in LN428 glioblastoma cells resulted in enhanced recruitment of XPC, a more rapid removal of digoxigenin-tagged psoralen adducts, and decreased cellular sensitivity to trioxsalen, implying that NEIL1 and BER may interfere the processing of ICLs. While exhibiting no enzymatic activity, purified NEIL1 protein bound to psoralen ICLs, in vitro. Our results indicate that NEIL1 recognizes specifically and distinctly ICLs in DNA and can obstruct the removal of crosslinks. In addition, we plan to further evaluate the recruitment of additional fluorescently-tagged fusion DNA repair proteins using laser microirradiation coupled with confocal microscopy in cell lines expressing various aging phenotypes.

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