Inhibition of eukaryotic DNA replication by geminin binding to Cdt1.
In all eukaryotic organisms, inappropriate firing of replication origins during the G2 phase of the cell cycle is suppressed by cyclin-dependent kinases. Multicellular eukaryotes contain a second putative inhibitor of re-replication called geminin. Geminin is believed to block binding of the mini-chromosome maintenance (MCM) complex to origins of replication, but the mechanism of this inhibition is unclear. Here we show that geminin interacts tightly with Cdt1, a recently identified replication initiation factor necessary for MCM loading. The inhibition of DNA replication by geminin that is observed in cell-free DNA replication extracts is reversed by the addition of excess Cdt1. In the normal cell cycle, Cdt1 is present only in G1 and S, whereas geminin is present in S and G2 phases of the cell cycle. Together, these results suggest that geminin inhibits inappropriate origin firing by targeting Cdt1.
Wohlschlegel
J A
JA
Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
Dwyer
B T
BT
Dhar
S K
SK
Cvetic
C
C
Walter
J C
JC
Dutta
A
A
D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism; D002474:Cell-Free System; D002843:Chromatin / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D019143:Evolution, Molecular; D016193:G1 Phase; D016195:G2 Phase; D064248:Geminin; D006367:HeLa Cells; D006801:Humans; D007399:Interphase; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011233:Precipitin Tests; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D018741:Replication Origin; D016196:S Phase; D014981:Xenopus; D029867:Xenopus Proteins
C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; C577998:GMNN protein, Xenopus; C577995:GMNN protein, human; D064248:Geminin; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins