title: UHRF1 depletion causes a G2/M arrest, activation of DNA damage response and apoptosis.
abstract: UHRF1 [ubiquitin-like protein, containing PHD (plant homeodomain) and RING finger domains 1] is required for cell cycle progression and epigenetic regulation. In the present study, we show that depleting cancer cells of UHRF1 causes activation of the DNA damage response pathway, cell cycle arrest in G2/M-phase and apoptosis dependent on caspase 8. The DNA damage response in cells depleted of UHRF1 is illustrated by: phosphorylation of histone H2AX on Ser139, phosphorylation of CHK (checkpoint kinase) 2 on Thr68, phosphorylation of CDC25 (cell division control 25) on Ser216 and phosphorylation of CDK1 (cyclin-dependent kinase 1) on Tyr15. Moreover, we find that UHRF1 accumulates at sites of DNA damage suggesting that the cell cycle block in UHRF1-depleted cells is due to an important role in damage repair. The consequence of UHRF1 depletion is apoptosis; cells undergo activation of caspases 8 and 3, and depletion of caspase 8 prevents cell death induced by UHRF1 knockdown. Interestingly, the cell cycle block and apoptosis occurs in p53-containing and -deficient cells. From the present study we conclude that UHRF1 links epigenetic regulation with DNA replication.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Tien
authors.forename: Sucharita
authors.initials: S
authors.lastname: Senbanerjee
authors.forename: Atul
authors.initials: A
authors.lastname: Kulkarni
authors.forename: Raksha
authors.initials: R
authors.lastname: Mudbhary
authors.forename: Bernadette
authors.initials: B
authors.lastname: Goudreau
authors.forename: Shridar
authors.initials: S
authors.lastname: Ganesan
authors.forename: Kirsten C
authors.initials: KC
authors.lastname: Sadler
authors.forename: Chinweike
authors.initials: C
authors.lastname: Ukomadu
mesh_terms: D017209:Apoptosis; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D064447:Checkpoint Kinase 2; D004249:DNA Damage / Q000528:radiation effects; D016195:G2 Phase; D020868:Gene Silencing; D006657:Histones / Q000378:metabolism; D006801:Humans; D020287:In Situ Nick-End Labeling; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering; D044767:Ubiquitin-Protein Ligases; D014466:Ultraviolet Rays / Q000009:adverse effects; D020687:cdc25 Phosphatases / Q000378:metabolism
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C406364:UHRF1 protein, human; D044767:Ubiquitin-Protein Ligases; D064447:Checkpoint Kinase 2; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D020687:cdc25 Phosphatases; C505407:CASP3 protein, human; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8