orc-2 Antibody
Description
Introduction to ORC2 Antibody
The ORC2 antibody is a monoclonal or polyclonal antibody targeting the Origin Recognition Complex subunit 2 (ORC2), a critical component of the eukaryotic DNA replication machinery . ORC2 is part of the six-subunit Origin Recognition Complex (ORC1-6), which binds to replication origins to initiate DNA replication by recruiting CDC6, CDT1, and the MCM2-7 helicase . Antibodies against ORC2 enable researchers to study its localization, interactions, and regulatory roles in DNA replication, heterochromatin organization, and mitosis .
Biological Significance of ORC2
ORC2 plays essential roles beyond DNA replication initiation:
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Heterochromatin Stability: ORC2 localizes to centromeres and telomeres, interacting with heterochromatin proteins (e.g., HP1α) to maintain chromatin compaction . Depletion causes heterochromatin decondensation and abnormal nuclear morphology .
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Mitotic Regulation: ORC2 is required for proper chromosome segregation. Knockdown leads to mitotic defects, including lagging chromosomes and micronuclei .
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Cell Cycle Checkpoints: Reduced ORC2 levels trigger replication stress, DNA damage, and G2/M arrest via ATM/CHK1 activation .
Development and Validation of ORC2 Antibodies
Key ORC2 antibodies and their properties:
Validation Methods:
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Immunofluorescence: Localizes ORC2 to centrosomes, centromeres, and heterochromatin foci .
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Functional Knockdown: siRNA or CRISPR/Cas9 depletion confirms antibody specificity via loss of ORC2 signal .
DNA Replication Studies
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Pre-Replication Complex (pre-RC) Assembly: ORC2 antibodies confirm ORC2’s role in loading MCM2-7 onto chromatin . Depletion reduces MCM2-7 chromatin association by 50–80% .
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Replication Stress: ORC2-deficient cells exhibit elevated γH2AX (DNA damage marker) and CHK1 activation .
Mitotic Regulation
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Chromosome Segregation: ORC2 depletion causes lagging chromosomes and micronuclei due to centromeric α-satellite decondensation .
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Cell Cycle Synchronization: Antibodies track ORC2 dynamics during G1/S transition and mitosis .
Epigenetic Studies
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Heterochromatin Interaction: Co-immunoprecipitation with HP1α and CENP-C demonstrates ORC2’s role in maintaining heterochromatin structure .
Cancer Biomarker Potential
ORC2 expression correlates with tumor progression in lung adenocarcinoma (LUAD):
| Pathological Parameter | ORC2 Expression (High vs. Low) | p-value |
|---|---|---|
| Lymph Node Metastasis | 23 vs. 7 | 0.0032 |
| TNM Stage (III–IV vs. I–II) | 5 vs. 25 | 0.2649 |
| Recurrence | 14 vs. 8 | 0.3552 |
Data source: LUAD patient cohort analysis .
Immune Infiltration
ORC2 expression inversely correlates with CD8+ T cells (p = 4.45e−07) and neutrophils (p = 9.39e−05), suggesting immune microenvironment modulation in cancer .
Key Research Findings
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ORC2 Depletion Survival: Human cells (HCT116, 293T) survive ORC2 knockout but exhibit slowed replication fork progression (~1.5 kb/min vs. 1.2 kb/min in wild type) .
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Phosphorylation Dynamics: Cyclin A-CDK2 phosphorylates ORC2 at Thr-116/226 during S phase, dissociating ORC from chromatin .
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ORCA Stabilization: ORC2 binding prevents ubiquitin-mediated degradation of ORCA/LRWD1, a pre-RC component .
Product Specs
**Constituents:** 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
Q&A
Here’s a structured collection of FAQs tailored for academic researchers working with ORC-2 antibodies, synthesized from peer-reviewed studies and technical documentation:
Advanced Research Questions
How to resolve contradictions in ORC-2’s dispensability for DNA replication?
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Data conflict analysis:
What advanced techniques characterize ORC-2’s interaction with heterochromatin?
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Integrated workflow:
How to address non-specific binding in ORC-2 Western blots?
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Troubleshooting table:
Data-Driven Insights
How does ORC-2 depletion affect epigenomic stability?
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Findings:
