title: The knock-down of ERCC1 but not of XPF causes multinucleation.
abstract: Excision repair cross complementing gene 1 (ERCC1) associated with xeroderma pigmentosum group F (XPF) is a heterodimeric endonuclease historically involved in the excision of bulky helix-distorting DNA lesions during nucleotide excision repair (NER) but also in the repair of DNA interstrand crosslinks. ERCC1 deficient mice show severe growth retardation associated with premature replicative senescence leading to liver failure and death at four weeks of age. In humans, ERCC1 is overexpressed in hepatocellular carcinoma and in the late G1 phase of hepatocyte cell cycle. To investigate whether ERCC1 could be involved in human hepatocyte cell growth and cell cycle progression, we knocked-down ERCC1 expression in the human hepatocellular carcinoma cell line Huh7 by RNA interference. ERCC1 knocked-down cells were delayed in their cell cycle and became multinucleated. This phenotype was rescued by ERCC1 overexpression. Multinucleation was not liver specific since it also occurred in HeLa and in human fibroblasts knocked-down for ERCC1. Multinucleated cells arose after drastic defects leading to flawed metaphase and cytokinesis. Interestingly, multinucleation did not appear after knocking-down other NER enzymes such as XPC and XPF, suggesting that NER deficiency was not responsible for multinucleation. Moreover, XPF mutant human fibroblasts formed multinucleated cells after ERCC1 knock-down but not after XPF knock-down. Therefore our results seem consistent with ERCC1 being involved in multinucleation but not XPF. This work reveals a new role for ERCC1 distinct from its known function in DNA repair, which may be independent of XPF. The role for ERCC1 in mitotic progression may be critical during development, particularly in humans.
authors.affiliation: EA4427 SeRAIC (Signaling and Responses to Infectious and Chemical Agents), Institut de Recherche en Santé, Environnement et Travail, Université de Rennes 1, 2 avenue du Pr L. Bernard, 35043 Rennes Cedex, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Rageul
authors.forename: Christophe
authors.initials: C
authors.lastname: Frëmin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Ezan
authors.forename: Georges
authors.initials: G
authors.lastname: Baffet
authors.forename: Sophie
authors.initials: S
authors.lastname: Langouët
mesh_terms: D045744:Cell Line, Tumor; D048750:Cell Nucleus Division / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004720:Endonucleases / Q000235:genetics* / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D000071518:Liver X Receptors; D008938:Mitosis / Q000235:genetics; D009154:Mutation / Q000235:genetics; D057093:Orphan Nuclear Receptors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D000071518:Liver X Receptors; D057093:Orphan Nuclear Receptors; C095888:xeroderma pigmentosum group F protein; C071447:ERCC1 protein, human; D004720:Endonucleases