Cdc20 Antibody

What is Cdc20 and what applications can Cdc20 antibodies be used for in research?

Cdc20 (cell division cycle 20 homolog) is an essential cell cycle regulator that promotes mitotic exit through activating the APC/C (Anaphase-Promoting Complex/Cyclosome) and monitors kinetochore-microtubule attachment through activating the Spindle Assembly Checkpoint (SAC) . Cdc20 antibodies can be used in multiple research applications:

The antibody has been extensively validated across these applications, with dozens of published studies citing its use in Western blotting (35 publications), immunohistochemistry (12 publications), and immunofluorescence (4 publications) .

What are the recommended dilutions for different applications of Cdc20 antibody?

Proper antibody dilution is critical for optimal results in different experimental applications. Based on extensive validation, the following dilutions are recommended for the 10252-1-AP Cdc20 antibody:

It is strongly recommended that researchers titrate the antibody for each specific experimental system to obtain optimal results, as the required concentration can be sample-dependent .

How should Cdc20 antibody be stored and handled for optimal performance?

For maximum stability and activity, Cdc20 antibody (10252-1-AP) should be stored according to these guidelines:

• Storage temperature: -20°C

• Buffer composition: PBS with 0.02% sodium azide and 50% glycerol at pH 7.3

• Stability: One year after shipment when properly stored

• Aliquoting: Not necessary for -20°C storage

• Special considerations: Small volume formats (20μl) contain 0.1% BSA for added stability

The antibody is supplied in liquid form after antigen affinity purification. The presence of glycerol and sodium azide in the storage buffer helps maintain antibody stability by preventing microbial contamination and protein denaturation during freeze-thaw cycles .

How can Cdc20 antibodies be used to investigate mitotic regulation and the Spindle Assembly Checkpoint?

Cdc20 antibodies provide powerful tools for investigating SAC function through several methodological approaches:

• Immunofluorescence co-localization studies: Cdc20 antibodies can be used to track the kinetochore localization of Cdc20 during mitosis. Research has shown that most Cdc20 mutants, except those lacking the ABBA-binding motif (Cdc20ΔABBA R), decorate kinetochores .

• Co-immunoprecipitation experiments: To study the interaction between Cdc20 and other SAC components, researchers can use Cdc20 antibodies to pull down protein complexes. This approach has revealed that mutations such as R162E/K163E or E180R/D203R in Cdc20 significantly impair checkpoint function by disrupting interactions with MCC (Mitotic Checkpoint Complex) .

• Mutational analysis with antibody detection: Researchers can introduce mutations in the CRY box of Cdc20 (e.g., CRY/3A, IPS/3A, or single mutations like R166A, Y167D, I168D) and use Cdc20 antibodies to detect the mutant proteins and correlate their expression with SAC defects .

• Phosphorylation state detection: Antibodies can be used to study Cdc20 phosphorylation, such as at Ser170 within the CRY box, which has been reported to be phosphorylated by Plk1 to facilitate Cdc20 degradation in G1 phase .

These approaches allow researchers to mechanistically dissect the roles of specific Cdc20 domains and residues in mitotic checkpoint function.

What methods can be used to validate CDC20 expression in cancer cells and its relationship to chromosomal instability?

Several complementary methods can be employed to quantify and validate CDC20 expression in cancer cell models, particularly when studying chromosomal instability:

• Immunofluorescence microscopy of single cells:

  • Synchronize cells to measure CDC20 at its peak expression during metaphase

  • Quantify CDC20 levels in individual cells to account for cell-to-cell variability

  • This method revealed significantly higher CDC20 levels in highly aneuploid cells compared to near-diploid counterparts

• Western blotting of synchronized cell populations:

  • Synchronize cells at prometaphase using Nocodazole

  • Harvest cells for protein extraction in RIPA buffer supplemented with protease inhibitors

  • Load 20-30 μg of protein on 7.5-10% polyacrylamide gels

  • Use CDC20 antibodies (recommended: Abcam ab26483 at 1:1000 dilution or Santa Cruz sc-13162 at 1:500 dilution)

  • Include loading controls such as β-Actin, GAPDH, or Vinculin

  • Detect using fluorescent secondary antibodies or chemiluminescence

  • Quantify band intensity using ImageJ or similar software

• Mitotic synchronization with MG-132 followed by release:

  • This approach allows tracking of CDC20 dynamics throughout mitotic progression

These methods consistently demonstrated that aneuploid cancer cells express significantly higher levels of CDC20 compared to their diploid counterparts, which correlates with increased sensitivity to SAC inhibition .

How can siRNA-mediated knockdown be used alongside CDC20 antibodies to study its function?

siRNA-mediated knockdown of CDC20 is a powerful approach for investigating its functional roles when combined with antibody-based detection methods:

Experimental protocol:

• Design or purchase custom siRNAs targeting CDC20 (e.g., 5′-CGGAAGACCUGCCGUUACAUU-3′)

• Include non-targeting control siRNA pools (e.g., Dharmacon D-001206-13)

• Optimize siRNA concentration based on cell type (e.g., 50 nM for HPT1/HPT2 cells, 25 nM for HCT116 cells)

• Transfect using Lipofectamine RNAiMAX (2.5 μl per ml of transfection medium)

• Verify knockdown efficiency by Western blot at 24h post-transfection using CDC20 antibodies

• Proceed with functional assays at appropriate timepoints:

  • Time-lapse microscopy: 20h post-transfection

  • EdU incorporation assays: 24h post-transfection

  • Western blot and qPCR analyses: 24h post-transfection

Key findings from CDC20 knockdown studies:

• CDC20 depletion decreases sensitivity to SAC inhibition in both mouse and human cells

• Cells with reduced CDC20 levels show prolonged metaphase duration

• Lower CDC20 expression correlates with decreased prevalence and severity of mitotic errors under SAC inhibition

• Prolonging mitosis duration through CDC20 depletion provides more time for cells to correct spindle abnormalities

These methodological approaches demonstrate how CDC20 antibodies can be integrated with knockdown strategies to elucidate functional aspects of CDC20 in mitotic regulation and chromosomal stability.

What are the critical considerations for optimizing Western blot protocols for CDC20 detection?

Western blotting for CDC20 requires specific optimization due to its cell cycle-regulated expression and multiple isoforms:

• Cell synchronization:

  • CDC20 levels fluctuate throughout the cell cycle, peaking during metaphase

  • For maximum and consistent detection, synchronize cells at prometaphase using Nocodazole before harvesting

  • Alternative synchronization methods include double thymidine block followed by release

• Protein extraction and loading:

  • Use RIPA buffer supplemented with protease inhibitor cocktail for consistent extraction

  • Maintain samples on ice during lysis (30 minutes) to prevent degradation

  • Load 20-30 μg of total protein for optimal signal-to-noise ratio

• Detection of CDC20 isoforms:

  • CDC20 exists in multiple protein isoforms that may affect mitotic duration

  • Use 7.5-10% polyacrylamide gels with sufficient resolution to separate closely migrating isoforms

  • When comparing isoform distribution between cell types, ensure equal loading and consistent exposure times

• Antibody selection and validation:

  • Different antibodies may preferentially detect specific CDC20 isoforms or epitopes

  • For comprehensive analysis, consider using antibodies targeting different regions (N-terminal vs. C-terminal)

  • Validate antibody specificity using siRNA knockdown controls

How can researchers effectively use CDC20 antibodies to study its role in cancer?

CDC20 expression has emerged as a significant factor in cancer cell sensitivity to SAC inhibition, which can be investigated using these methodological approaches:

• Correlation of CDC20 expression with sensitivity to SAC inhibitors:

  • Quantify CDC20 expression levels using Western blot or immunofluorescence

  • Treat cells with SAC inhibitors (e.g., MPS1 inhibitors MPI-0479605 and AZ3146)

  • Measure cell survival or mitotic outcomes using appropriate assays

  • Analysis of over 1700 human cancer cell lines revealed increased CDC20 expression correlates with increased sensitivity to SAC inhibitor drugs

• Comparison between diploid and aneuploid cancer models:

  • Use isogenic cell line pairs such as HCT116 (diploid) and HPT1/HPT2 (aneuploid derivatives)

  • Quantify CDC20 levels in synchronized populations

  • Highly aneuploid cells consistently express significantly higher CDC20 levels compared to their near-diploid counterparts

• CDC20 knockdown to alter sensitivity to SAC inhibition:

  • Perform partial CDC20 knockdown in cancer cells using optimized siRNA concentrations

  • Challenge with SAC inhibitors and measure mitotic outcomes

  • CDC20 depletion significantly reduces the sensitivity to SAC inhibition, resulting in:

    • Prolonged metaphases

    • Decreased prevalence of mitotic errors

    • Improved cell survival under SAC inhibition

These approaches demonstrate how CDC20 antibodies can be integrated into comprehensive research strategies to understand its role in cancer progression and response to targeted therapies.

How can CDC20 antibodies be used to study chromosomal instability (CIN) in cancer models?

Chromosomal instability is a hallmark of many cancers, and CDC20 plays a critical role in this process. Researchers can employ the following methods using CDC20 antibodies:

• Experimental induction of CIN:

  • Treat cells with 125 nM Reversine (an MPS1 inhibitor) for 24h

  • Allow cells to recover for an additional 36h following Reversine wash-off

  • Collect cells for analysis using CDC20 antibodies to correlate CDC20 levels with CIN phenotypes

• Live cell imaging with CDC20 knockdown during CIN induction:

  • Transfect cells with CDC20 siRNA

  • 20h post-transfection, add Reversine or DMSO (control)

  • Perform time-lapse microscopy to observe mitotic progression and errors

  • This approach has revealed that CDC20 depletion can partially rescue the mitotic defects induced by SAC inhibition

• Cell cycle analysis with CDC20 immunostaining:

  • Combine CDC20 antibody staining with EdU incorporation

  • Harvest cells 2h after EdU pulse

  • This enables correlation between CDC20 expression, cell cycle phase, and chromosomal instability

These methodological approaches using CDC20 antibodies have revealed that increased expression of CDC20 is significantly associated with an increase in mitotic errors, while CDC20 depletion results in prolonged metaphases and decreased prevalence and severity of mitotic errors under SAC inhibition .

What are the methodological considerations when studying CDC20 protein dynamics during mitosis?

CDC20 protein levels and localization change dynamically during mitosis, requiring specialized techniques for comprehensive analysis:

• Live cell imaging approaches:

  • While fixed cell immunofluorescence provides valuable snapshots, it cannot capture dynamic changes

  • Future studies would benefit from genetically labeling endogenous CDC20 for live cell imaging

  • This would allow researchers to follow CDC20 levels in real-time during normal and abnormal mitosis

• Single-cell analysis vs. population-based approaches:

  • Population-based methods like Western blotting after synchronization provide average CDC20 levels

  • Single-cell immunofluorescence reveals cell-to-cell variability in CDC20 expression

  • Both approaches have confirmed higher CDC20 expression in aneuploid vs. diploid cells

• Analysis of CDC20 post-translational modifications:

  • CDC20 function is regulated by phosphorylation, such as Plk1-mediated phosphorylation at Ser170

  • Researchers can use phospho-specific antibodies or general CDC20 antibodies after phosphatase treatment

  • These modifications may influence CDC20's role in SAC function and APC/C activation

• Functional rescue experiments:

  • After CDC20 knockdown, researchers can reintroduce RNAi-resistant CDC20 variants

  • This approach has been used to demonstrate that metaphase arrest caused by RNAi in knockout cells was fully rescued by reintroducing RNAi-resistant YFP-CDC20

  • Similar strategies can test the functional significance of specific CDC20 domains and residues

Understanding these methodological considerations is essential for researchers seeking to analyze CDC20's complex roles in mitotic regulation and cancer progression.