Mechanisms of MCM2-7 loading and initial DNA melting at near base-pair resolution [MCM4 & ORC2 ChIP-exo]
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA725895 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR14350322.fastq.gz | Fastqsanger.gz | |||
| SRR14350323.fastq.gz | Fastqsanger.gz | |||
| SRR14350324.fastq.gz | Fastqsanger.gz | |||
| SRR14350325.fastq.gz | Fastqsanger.gz | |||
| SRR14350326.fastq.gz | Fastqsanger.gz |
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Project description:The loading and activation of the replicative helicase MCM2-7 are key events during the G1-S phase transition. In budding yeast, the origin recognition complex (ORC) binds to the conserved DNA elements A and B1 of the autonomously replicating sequence (ARS). This is followed by the consecutive loading of two MCM2-7 hetero-hexamers into a MCM2-7 double-hexamer (DH). In S-phase the MCM2-7 DH is activated, resulting in two Cdc45-MCM-GINS (CMG) helicases that bidirectionally unwind DNA ahead of the replication fork. Here, we show that MCM2-7 helicase loading across the B1 element displaces ORC from origins. This allows ORC binding and helicase loading at lower affinity binding sites and origins throughout the genome. Furthermore, we mapped the sites of initial DNA unwinding genome-wide and show that these sites appear near the N-terminal domains of the MCM2-7 double-hexamer in proximity of the B1 element. Finally, employing a chemical-biology approach, we establish that during helicase activation the Mcm2/5 interface acts as the DNA exit gate for single-stranded-DNA extrusion. Our work identifies that helicase loading follows a distributive mechanism, allowing for equal MCM2-7 loading across the genome and surprisingly finds that DNA unwinding initiates from the helicase N-terminal interface in proximity to the ARS B1 element.
2024-06-21 | GSE173527 | GEO
Project description:The loading and activation of the replicative helicase MCM2-7 are key events during the G1-S phase transition.In budding yeast, the origin recognition complex (ORC) binds to the conserved DNA elements A and B1 of the autonomously replicating sequence (ARS).This is followed by the consecutive loading of two MCM2-7 hetero-hexamers into a MCM2-7 double-hexamer(DH).In S-phase the MCM2-7DH is activated, resulting in two Cdc45-MCM-GINS(CMG) helicases that bidirectionally unwind DNA ahead of the replication fork.Here,we show that MCM2-7 helicase loading across the B1 element displaces ORC fromo rigins.This allows ORC binding and helicase loading at lower affinity binding sites and origins throughout the genome.Furthermore, we mapped the sites of initial DNA unwinding genome-wide and show that these sites appear near the N-terminal domains of the MCM2-7 double-hexamer in proximity of the B1 element.Finally, employing a chemical-biology approach, we establish that during helicase activation the Mcm2/5 interface acts as the DNA exit gate for single-stranded-DNA extrusion.Our work identifies that helicase loading follows a distributive mechanism, allowing for equal MCM2-7 loading across the genome and surprisingly finds that DNA unwinding initiates from the helicase N-terminal interface in proximity to the ARS B1 element.
2024-06-21 | GSE240472 | GEO
Project description:Mechanisms of MCM2-7 loading and initial DNA melting at near base-pair resolution
| PRJNA1003856 | ENA
Project description:Determination of the genome-wide distribution of the Mcm2-7 helicase by chromatin immunoprecipitation in the Drosophila Kc167 cell line at the beginning of S phase. Kc167 cells were arrested at the G1/S transition with hydroxyurea (HU). Goal was to evaluate changes in the genome-wide Mcm2-7 distribution throughout the cell cycle, and how this relates to the excess Mcm2-7 loaded onto chromatin in G1. ChIP-Chip of Mcm2-7 in HU compared to input genomic DNA. Biological Replicates: 2
2014-11-27 | E-GEOD-63680 | biostudies-arrayexpress
Project description:In eukaryotes, the hetero-hexameric origin recognition complex (ORC) is responsible for assembling Mcm2-7 complex into a head-to-head double hexamer (DH), forming pre-replicative complex (pre-RC) that licenses origin DNA for replication initiation. This process is tightly controlled throughout the cell cycle to ensure accurate duplication of the genome. Here we show that the N-terminal intrinsically disordered region (IDR) of the yeast Orc2 subunit plays a critical role in promoting pre-RC assembly. We found that removing a short segment (residues 175-200) from Orc2-IDR or mutating a key isoleucine (194) in this region significantly inhibits replication initiation across the genome and causes cell death. Although the Orc2-IDR mutants can still assemble the ORC-Cdc6-Cdt1-Mcm2-7 (OCCM) intermediate on DNA, the assembled mutant OCCM exhibits impaired ATP hydrolysis, preventing its conversion into Mcm2-7-ORC (MO) complex and subsequent DH formation. Interestingly, our in vitro assays showed that adding the Orc2-IDR peptide in the pre-RC reactions can rescue this defect. Furthermore, phosphorylation of this Orc2-IDR motif by S-cyclin dependent kinase (S-CDK) blocks its binding to Mcm2, leading to defective pre-RC assembly. Our findings provide crucial mechanistic insights into the multifaceted roles of ORC in modulating MCM loading to support origin licensing during the G1 phase and its regulation to restrict origin firing within the S phase.
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Project description:Determination of the genome-wide distribution of the Mcm2-7 helicase by chromatin immunoprecipitation in the Drosophila Kc167 cell line at the beginning of S phase. Kc167 cells were arrested at the G1/S transition with hydroxyurea (HU). Goal was to evaluate changes in the genome-wide Mcm2-7 distribution throughout the cell cycle, and how this relates to the excess Mcm2-7 loaded onto chromatin in G1.
2014-11-27 | GSE63680 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE31889: ChIP-chip from Drosophila egg chambers using MCM2-7 antibody GSE31890: ChIP-chip from Drosophila egg chambers using ORC2 antibody Refer to individual Series
2011-09-06 | E-GEOD-31891 | biostudies-arrayexpress
Project description:Chromatin immunoprecipitation of the MCM2-7 replicative helicase followed by hybridization to genome-wide tiling microarrays demonstrated that MCMs localize to the follicle cell amplicons at stages of replication initiation Comparison of MCM2-7 ChIP sample compared to input DNA for Drosophila egg chambers
2011-09-06 | E-GEOD-31889 | biostudies-arrayexpress
Project description:Mcm2, a subunit of the Mcm2-7 helicase best known for its role in DNA replication, contains a histone binding motif that facilitates the transfer of parental histone following DNA replication. Here we show that Mcm2 is important for the differentiation of mouse embryonic stem (ES) cells. Mcm2-2A mutation defective in histone binding impairs differentiation and programmatic changes in gene expression and histone modifications during differentiation. Mcm2 localizes at the transcription starting sites and the binding of Mcm2 at gene promoters is disrupted in both Mcm2-2A ES cells and neuro-precursor cells (NPCs). Reduced Mcm2 binding in Mcm2-2A ES cells correlates with decreased chromatin accessibility at bivalent chromatin domains containing repressive H3K27me3 and active H3K4me3 modifications in NPCs. Together, our studies reveal a novel function of Mcm2 in ES differentiation, likely through manipulating chromatin landscape at bivalent chromatin domains.
2022-11-16 | GSE203271 | GEO
Project description:Mcm2, a subunit of the Mcm2-7 helicase best known for its role in DNA replication, contains a histone binding motif that facilitates the transfer of parental histone following DNA replication. Here we show that Mcm2 is important for the differentiation of mouse embryonic stem (ES) cells. Mcm2-2A mutation defective in histone binding impairs differentiation and programmatic changes in gene expression and histone modifications during differentiation. Mcm2 localizes at the transcription starting sites and the binding of Mcm2 at gene promoters is disrupted in both Mcm2-2A ES cells and neuro-precursor cells (NPCs). Reduced Mcm2 binding in Mcm2-2A ES cells correlates with decreased chromatin accessibility at bivalent chromatin domains containing repressive H3K27me3 and active H3K4me3 modifications in NPCs. Together, our studies reveal a novel function of Mcm2 in ES differentiation, likely through manipulating chromatin landscape at bivalent chromatin domains.
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