The MCM3 acetylase MCM3AP inhibits initiation, but not elongation, of DNA replication via interaction with MCM3.
Minichromosome maintenance (MCM) proteins are essential components of pre-replication complexes, which limit DNA replication to once per cell cycle. MCM3 acetylating protein, MCM3AP, binds and acetylates MCM3 and inhibits cell cycle progression. In the present study, we examined inhibition of the cell cycle by MCM3AP in a cell-free system. We show here that wild type MCM3AP, but not the acetylase-deficient mutant, inhibits initiation of DNA replication, but not elongation. Both wild type and acetylase-deficient mutant MCM3AP, however, can bind to chromatin through interaction with MCM3. These results indicate that MCM3 acetylase activity of MCM3AP is required to inhibit initiation of DNA replication and that association of MCM3AP to chromatin alone is not sufficient for the inhibition. We also show that interaction between MCM3 and MCM3AP is essential for nuclear localization and chromatin binding of MCM3AP. Furthermore, the chromatin binding of MCM3AP is temporally correlated with that of endogenous MCM3 when cells were released from mitosis. Hence, MCM3AP is a potent natural inhibitor of the initiation of DNA replication whose action is mediated by interaction with MCM3.
Takei
Yoshinori
Y
Medical Research Council (MRC) Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 2XZ, United Kingdom. yt215@cam.ac.uk
Assenberg
Magdalena
M
Tsujimoto
Gozoh
G
Laskey
Ronald
R
D000123:Acetyltransferases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D064111:Minichromosome Maintenance Complex Component 2; D064126:Minichromosome Maintenance Complex Component 3; D064148:Minichromosome Maintenance Complex Component 4; D009687:Nuclear Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D014157:Transcription Factors; D014162:Transfection
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C066470:MCM3 protein, human; D009687:Nuclear Proteins; D010750:Phosphoproteins; D014157:Transcription Factors; D000123:Acetyltransferases; C406825:MCM3AP protein, human; C099243:MCM4 protein, human; D064111:Minichromosome Maintenance Complex Component 2; D064126:Minichromosome Maintenance Complex Component 3; D064148:Minichromosome Maintenance Complex Component 4