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Amin A, Wu R, Khan MA, Cheung MH, Liang Y, Liu C, Zhu G, Yu ZL, Liang C. An essential Noc3p dimerization cycle mediates ORC double-hexamer formation in replication licensing. Life Sci Alliance 2023; 6:e202201594. [PMID: 36599624 PMCID: PMC9813392 DOI: 10.26508/lsa.202201594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 01/05/2023] Open
Abstract
Replication licensing, a prerequisite of DNA replication, helps to ensure once-per-cell-cycle genome duplication. Some DNA replication-initiation proteins are sequentially loaded onto replication origins to form pre-replicative complexes (pre-RCs). ORC and Noc3p bind replication origins throughout the cell cycle, providing a platform for pre-RC assembly. We previously reported that cell cycle-dependent ORC dimerization is essential for the chromatin loading of the symmetric MCM double-hexamers. Here, we used Saccharomyces cerevisiae separation-of-function NOC3 mutants to confirm the separable roles of Noc3p in DNA replication and ribosome biogenesis. We also show that an essential and cell cycle-dependent Noc3p dimerization cycle regulates the ORC dimerization cycle. Noc3p dimerizes at the M-to-G1 transition and de-dimerizes in S-phase. The Noc3p dimerization cycle coupled with the ORC dimerization cycle enables replication licensing, protects nascent sister replication origins after replication initiation, and prevents re-replication. This study has revealed a new mechanism of replication licensing and elucidated the molecular mechanism of Noc3p as a mediator of ORC dimerization in pre-RC formation.
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Affiliation(s)
- Aftab Amin
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Rentian Wu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Muhammad Ajmal Khan
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Man Hei Cheung
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yanting Liang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Changdong Liu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Guang Zhu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhi-Ling Yu
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Chun Liang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- EnKang Pharmaceuticals (Guangzhou), Ltd., Guangzhou, China
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Amin A, Wu R, Cheung MH, Scott JF, Wang Z, Zhou Z, Liu C, Zhu G, Wong CKC, Yu Z, Liang C. An Essential and Cell-Cycle-Dependent ORC Dimerization Cycle Regulates Eukaryotic Chromosomal DNA Replication. Cell Rep 2021; 30:3323-3338.e6. [PMID: 32160540 DOI: 10.1016/j.celrep.2020.02.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 10/04/2019] [Accepted: 02/10/2020] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic DNA replication licensing is a prerequisite for, and plays a role in, regulating genome duplication that occurs exactly once per cell cycle. ORC (origin recognition complex) binds to and marks replication origins throughout the cell cycle and loads other replication-initiation proteins onto replication origins to form pre-replicative complexes (pre-RCs), completing replication licensing. However, how an asymmetric single-heterohexameric ORC structure loads the symmetric MCM (minichromosome maintenance) double hexamers is controversial, and importantly, it remains unknown when and how ORC proteins associate with the newly replicated origins to protect them from invasion by histones. Here, we report an essential and cell-cycle-dependent ORC "dimerization cycle" that plays three fundamental roles in the regulation of DNA replication: providing a symmetric platform to load the symmetric pre-RCs, marking and protecting the nascent sister replication origins for the next licensing, and playing a crucial role to prevent origin re-licensing within the same cell cycle.
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Affiliation(s)
- Aftab Amin
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China; Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Rentian Wu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Man Hei Cheung
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - John F Scott
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ziyi Wang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zijing Zhou
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Changdong Liu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Guang Zhu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Chris Kong-Chu Wong
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Zhiling Yu
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China.
| | - Chun Liang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China; The First Clinical Medicine College, Guangzhou University of Chinese Medicine, Guangzhou, China; EnKang Pharmaceuticals Limited, Guangzhou, China.
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