title: The Rothmund-Thomson gene product RECQL4 localizes to the nucleolus in response to oxidative stress.
abstract: Mutations in the RECQL4 helicase gene have been linked to Rothmund-Thomson syndrome (RTS), which is characterized by poikiloderma, growth deficiency, and a predisposition to cancer. Examination of RECQL4 subcellular localization in live cells demonstrated a nucleoplasmic pattern and, to a lesser degree, staining in nucleoli. Analysis of RECQL4-GFP deletion mutants revealed two nuclear localization regions in the N-terminal region of RECQL4 and a nucleolar localization signal at amino acids 376-386. RECQL4 localization did not change after treatment with the DNA-damaging agents bleomycin, etoposide, UV irradiation and gamma irradiation, in contrast to the Bloom and Werner syndrome helicases that relocate to distinct nuclear foci after damage. However, in a significant number of cells exposed to hydrogen peroxide or streptonigrin, RECQL4 accumulated in nucleoli. Using a T7 phage display screen, we determined that RECQL4 interacts with poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme that promotes genomic integrity through its involvement in DNA repair and signaling pathways. The RECQL4 nucleolar localization was inhibited by pretreatment with a PARP-1 inhibitor. The C-terminal portion of RECQL4 was found to be an in vitro substrate for PARP-1. These results demonstrate changes in the intracellular localization of RECQL4 in response to oxidative stress and identify an interaction between RECQL4 and PARP-1.
authors.affiliation: Department of Pathology, University of Chicago, MC1089, Chicago, IL 60637, USA.
authors.forename: Leslie L
authors.initials: LL
authors.lastname: Woo
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Futami
authors.forename: Akira
authors.initials: A
authors.lastname: Shimamoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Furuichi
authors.forename: Karen M
authors.initials: KM
authors.lastname: Frank
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism*; D002467:Cell Nucleus / Q000737:chemistry; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D018384:Oxidative Stress; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D053484:RecQ Helicases
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D000251:Adenosine Triphosphatases; C506731:RECQL4 protein, human; D004265:DNA Helicases; D053484:RecQ Helicases