Loss of Geminin induces rereplication in the presence of functional p53.
Strict regulation of DNA replication is essential to ensure proper duplication and segregation of chromosomes during the cell cycle, as its deregulation can lead to genomic instability and cancer. Thus, eukaryotic organisms have evolved multiple mechanisms to restrict DNA replication to once per cell cycle. Here, we show that inactivation of Geminin, an inhibitor of origin licensing, leads to rereplication in human normal and tumor cells within the same cell cycle. We found a CHK1-dependent checkpoint to be activated in rereplicating cells accompanied by formation of gammaH2AX and RAD51 nuclear foci. Abrogation of the checkpoint leads to abortive mitosis and death of rereplicated cells. In addition, we demonstrate that the induction of rereplication is dependent on the replication initiation factors CDT1 and CDC6, and independent of the functional status of p53. These data show that Geminin is required for maintaining genomic stability in human cells.
Melixetian
Marina
M
Department of Experimental Oncology, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy.
Ballabeni
Andrea
A
Masiero
Laura
L
Gasparini
Patrizia
P
Zamponi
Raffaella
R
Bartek
Jiri
J
Lukas
Jiri
J
Helin
Kristian
K
D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000235:genetics; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D000071877:Checkpoint Kinase 1; D004261:DNA Replication / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D064248:Geminin; D018816:Genes, cdc / Q000502:physiology; D042822:Genomic Instability / Q000235:genetics*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008938:Mitosis / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011123:Polyploidy; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
C103706:CDC6 protein, human; C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C577995:GMNN protein, human; D064248:Geminin; C468783:H2AX protein, human; D006657:Histones; D009687:Nuclear Proteins; D016159:Tumor Suppressor Protein p53; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C495153:RAD51 protein, human; D051135:Rad51 Recombinase