TY - JOUR
T1 - An essential Noc3p dimerization cycle mediates ORC double-hexamer formation in replication licensing
AU - Amin, Aftab
AU - Wu, Rentian
AU - Khan, Muhammad Ajmal
AU - Cheung, Man Hei
AU - Liang, Yanting
AU - Liu, Changdong
AU - Zhu, Guang
AU - Yu, Zhi Ling
AU - Liang, Chun
N1 - Funding information:
We thank Profs. Bruce Stillman and Ulrich Laemmli for the kind gifts of yeast strains, plasmids and/or antibodies. We would also like to thank Yuanliang Zhai and Kelvin KL Sou for their suggestions and technical assistance. Supported by the Hong Kong Research Grants Council [GRF661713 and GRF16104521], the Guangzhou Innovation and Entrepreneurship Leading Team Project [202009020005], the Science and Technology Innovation Bureau of Guangzhou Development District [CY2019-005], and Hong Kong Baptist University, Research Committee, Initiation Grant - Faculty Niche Research Areas (IG-FNRA) 2018/19 [RC-FNRA-IG-18-19-SCM-01]. Funding for open access charge: Hong Kong Research Grants Council.
Publisher Copyright:
© 2023 Amin et al.
PY - 2023/3
Y1 - 2023/3
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85145539432&partnerID=8YFLogxK
U2 - 10.26508/lsa.202201594
DO - 10.26508/lsa.202201594
M3 - Journal article
C2 - 36599624
AN - SCOPUS:85145539432
SN - 2575-1077
VL - 6
JO - Life Science Alliance
JF - Life Science Alliance
IS - 3
M1 - e202201594
ER -