SPAC23G3.12c Antibody

What is SPAC23G3.12c and why is it important in fission yeast research?

SPAC23G3.12c is a serine protease in Schizosaccharomyces pombe (strain 972 / ATCC 24843) identified through comparative proteomic and transcriptomic profiling . The protein has been detected in fission yeast proteome analyses with a relative abundance value of 2.6886 (±0.1181) . Its importance in research lies in understanding protease functions in cellular processes of fission yeast, which serves as a model organism for studying eukaryotic biology.

What types of SPAC23G3.12c antibodies are available for research?

Currently, polyclonal antibodies raised in rabbit against recombinant Schizosaccharomyces pombe SPAC23G3.12c protein are commercially available . These antibodies are typically supplied in liquid form, preserved with 0.03% Proclin 300 in a buffer consisting of 50% Glycerol and 0.01M PBS at pH 7.4 . They are purified using antigen affinity methods.

Which applications are validated for SPAC23G3.12c antibodies?

SPAC23G3.12c antibodies have been validated for several standard laboratory techniques:

These applications are primarily used for detecting the native protein in fission yeast samples .

How is gene expression of SPAC23G3.12c affected by experimental conditions?

Gene expression of SPAC23G3.12c shows downregulation under nitrogen starvation conditions. The experimental data demonstrates:

Note: -N+P indicates nitrogen starvation in the presence of P-factor, while -N-P indicates nitrogen starvation in the absence of P-factor .

How can researchers optimize Western blot protocols specifically for SPAC23G3.12c detection?

For optimal Western blot detection of SPAC23G3.12c:

• Sample preparation: Extract total protein from S. pombe cells using glass bead disruption in lysis buffer containing protease inhibitors to prevent degradation of the serine protease.

• Gel separation: Use 10-12% SDS-PAGE gels for optimal resolution of SPAC23G3.12c.

• Transfer conditions: Transfer to PVDF membranes (preferred over nitrocellulose for this protein) at 100V for 60 minutes or 30V overnight at 4°C.

• Blocking: Block with 5% non-fat dry milk in TBST for 1 hour at room temperature.

• Primary antibody: Dilute antibody 1:500 to 1:1000 in blocking solution and incubate overnight at 4°C.

• Washing: Wash 4× with TBST for 5 minutes each.

• Secondary antibody: Use anti-rabbit HRP-conjugated antibody at 1:5000 dilution for 1 hour at room temperature.

• Detection: Use enhanced chemiluminescence detection with exposure times of 30 seconds to 5 minutes depending on expression levels .

What are the considerations for using SPAC23G3.12c antibodies in immunoprecipitation experiments?

When using SPAC23G3.12c antibodies for immunoprecipitation:

• Lysis conditions: Use gentle lysis buffers (e.g., 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 1% NP-40, 0.5% sodium deoxycholate) that preserve protein-protein interactions.

• Antibody amounts: Use 2-5 μg of antibody per 500 μg of total protein lysate.

• Pre-clearing: Pre-clear lysates with protein A agarose or magnetic beads for 1 hour at 4°C to reduce non-specific binding.

• Incubation time: Incubate lysates with antibody overnight at 4°C under gentle rotation.

• Bead selection: Use protein A or protein A/G mix for rabbit polyclonal antibodies.

• Washes: Perform at least 4 washes with lysis buffer followed by 2 washes with PBS to reduce background.

• Controls: Always include a negative control using non-immune rabbit IgG to distinguish specific from non-specific binding.

• Elution: Use either acidic conditions (0.1 M glycine, pH 2.5) or SDS sample buffer, depending on downstream applications .

How can researchers validate the specificity of SPAC23G3.12c antibodies?

To validate antibody specificity:

• Knockout/knockdown controls: Test the antibody on samples from SPAC23G3.12c deletion strains, which should show no signal. Deletion libraries containing SPAC23G3.12c mutants have been created for fission yeast .

• Overexpression testing: Compare signals between wild-type and SPAC23G3.12c-overexpressing strains.

• Peptide competition assay: Pre-incubate the antibody with excess purified antigen before application to the sample. This should eliminate specific binding.

• Cross-reactivity assessment: Test the antibody against lysates from other related yeast species to evaluate cross-reactivity.

• Mass spectrometry validation: Perform immunoprecipitation followed by mass spectrometry analysis to confirm that the captured protein is indeed SPAC23G3.12c.

• Multiple antibody comparison: If available, compare results using different antibodies targeting different epitopes of SPAC23G3.12c .

What are the considerations for studying SPAC23G3.12c expression during cell cycle progression?

When investigating SPAC23G3.12c expression across the cell cycle:

• Synchronization methods:

  • Nitrogen starvation and release works well for S. pombe but affects SPAC23G3.12c expression levels directly

  • Temperature-sensitive cdc25 mutants allow for G2 synchronization without affecting nutrient status

  • Lactose gradient centrifugation provides physical separation of cells at different stages

• Sampling frequency: Collect samples every 20-30 minutes for 4-5 hours to cover the complete S. pombe cell cycle.

• Expression analysis:

  • Compare SPAC23G3.12c protein levels with known cell cycle markers

  • Use flow cytometry for DNA content analysis to confirm cell cycle stages

  • Consider dual protein/mRNA analysis as mRNA-protein correlation may vary during cell cycle

• Data normalization: Normalize to housekeeping genes with stable expression across the cell cycle, such as act1+ (actin) or cdc2+ .

How can SPAC23G3.12c antibodies be used in immunofluorescence microscopy?

For immunofluorescence microscopy with SPAC23G3.12c antibodies:

• Cell fixation:

  • For preserving cell wall and membrane: Fix cells with 3.7% formaldehyde for 30 minutes at room temperature

  • For better antibody penetration: Create spheroplasts using zymolyase (1mg/ml) in 1.2M sorbitol buffer

• Permeabilization: Use 0.1% Triton X-100 for 5 minutes after fixation to allow antibody access.

• Blocking: Block with 5% BSA or 5% normal goat serum in PBS for 1 hour.

• Primary antibody incubation: Dilute SPAC23G3.12c antibody 1:100 to 1:250 in blocking buffer and incubate overnight at 4°C or 2 hours at room temperature.

• Secondary antibody: Use fluorophore-conjugated anti-rabbit antibodies (Alexa Fluor 488 or 594) at 1:500 dilution.

• Counterstaining: DAPI (1 μg/ml) for nuclei and Bodipy for lipid droplets if studying cytoplasmic distribution .

• Mounting: Mount in anti-fade medium containing 50% glycerol and 50mM n-propyl gallate.

• Controls: Include peptide competition controls and secondary-only controls .

What approaches can be used to study the interaction of SPAC23G3.12c with other proteins?

To study protein interactions of SPAC23G3.12c:

• Co-immunoprecipitation: Using SPAC23G3.12c antibodies to pull down the protein complex followed by Western blot or mass spectrometry to identify interacting partners.

• Yeast two-hybrid assays: Create fusion constructs of SPAC23G3.12c with DNA binding domains and test against activation domain fusion libraries.

• Proximity labeling: BioID or APEX2 fusion to SPAC23G3.12c to identify proximal proteins in living cells.

• FRET/BRET analysis: Generate fluorescent protein fusions to study direct interactions in live cells.

• Crosslinking approaches: Chemical crosslinking followed by immunoprecipitation and mass spectrometry (CLIP-MS) can identify transient interactors.

• Analysis validation: Confirm interactions by reciprocal co-IPs and by demonstrating functional relationships between interacting proteins in genetic studies .

How can researchers investigate the functional role of SPAC23G3.12c under stress conditions?

To study SPAC23G3.12c function under stress:

• Stress induction protocols:

  • Nitrogen starvation: Transfer cells to EMM lacking nitrogen source

  • Temperature stress: Shift from 30°C to 37°C (heat) or 16°C (cold)

  • Oxidative stress: Add H₂O₂ (0.5-2mM) or menadione (0.1-0.5mM)

  • Osmotic stress: Add sorbitol (1-2M) or KCl (0.6-1.2M)

• Time-course analysis: Monitor changes in:

  • Protein levels using Western blot with SPAC23G3.12c antibody

  • Subcellular localization using immunofluorescence

  • Protease activity using specific substrates

• Genetic approaches:

  • Compare wild-type with SPAC23G3.12c deletion strains

  • Use temperature-sensitive mutants if deletion is lethal

  • Create catalytically inactive mutants to distinguish structural from enzymatic roles

• Transcriptional response:

  • Monitor SPAC23G3.12c mRNA levels in parallel with protein levels

  • Note that under nitrogen starvation, SPAC23G3.12c shows significant downregulation

• Phenotypic assays:

  • Cell survival quantification

  • Growth rate measurements

  • Microscopic analysis of cellular morphology and cytoplasmic state

What considerations are important when developing quantitative assays for SPAC23G3.12c protein levels?

For quantitative measurement of SPAC23G3.12c:

• Sample preparation standardization:

  • Use consistent cell numbers (1×10⁷ cells per sample)

  • Standardize growth conditions and harvesting phase

  • Include complete protease inhibitor cocktails in lysis buffers

• Western blot quantification:

  • Use housekeeping proteins like Cdc2 or α-tubulin as loading controls

  • Employ secondary antibodies with linear detection range

  • Utilize chemiluminescence detection with multiple exposure times

  • Apply densitometry software with background correction

• ELISA development:

  • Optimize coating conditions (typically 100μl of 1-10μg/ml purified antigen)

  • Determine optimal antibody concentrations (typically 0.1-5μg/ml)

  • Establish standard curves using recombinant protein

  • Use TMB substrate with absorbance measurement at 450nm

• Data normalization approaches:

  • Normalize to cell number, total protein, or specific reference proteins

  • Apply statistical modeling to normalize spectral counts in mass spectrometry approaches

• Technical considerations:

  • Account for the mRNA-protein correlation which may vary under different conditions

  • Consider that the relative abundance of SPAC23G3.12c may change significantly under different physiological states

How can researchers use SPAC23G3.12c antibodies to study cytoplasmic freezing phenomena in fission yeast?

For studying cytoplasmic freezing (CF) with SPAC23G3.12c antibodies:

• CF induction protocol:

  • Follow standard protocols for CF induction in fission yeast cells

  • Use glucose starvation methods to induce quiescence and CF

• Immunofluorescence analysis:

  • Compare SPAC23G3.12c localization in normal versus CF states

  • Use dual labeling with lipid droplet markers (Bodipy) and SPAC23G3.12c antibodies

  • Analyze correlation coefficient for quantification of particle motion

• Cell wall considerations:

  • For CF cells, optimize cell wall digestion using modified protocols:

    • Prepare 1.2M sorbitol buffer (1.2M sorbitol, 0.1M sodium phosphate, pH 6.5)

    • Create 0.5M sorbitol buffer (0.5M sorbitol, 0.1M sodium phosphate, pH 6.5)

    • Treat with zymolyase (1mg/ml) in appropriate buffer

• Image analysis methods:

  • Apply single particle tracking of lipid droplets

  • Calculate mean squared displacement of mitochondria

  • Determine Bodipy correlation coefficient for quantification of lipid droplet motion

• Deletion strain analysis:

  • Compare CF induction in wild-type versus SPAC23G3.12c deletion strains

  • Screen for genetic interactions between SPAC23G3.12c and other genes required for CF

What controls should be included when using SPAC23G3.12c antibodies in chromatin immunoprecipitation (ChIP) experiments?

When performing ChIP with SPAC23G3.12c antibodies:

• Essential controls:

  • Input DNA (pre-immunoprecipitation sample): 5-10% of chromatin before IP

  • No-antibody control: Perform IP procedure without adding antibody

  • Non-specific IgG control: Use same amount of non-immune rabbit IgG

  • Positive control regions: Known targets of serine proteases

  • Negative control regions: Heterochromatic regions unlikely to be bound

• Cell preparation:

  • Optimal crosslinking: 1% formaldehyde for 15 minutes at room temperature

  • Crosslinking quenching: 125mM glycine for 5 minutes

  • Cell lysis: Glass bead disruption optimal for fission yeast

• Sonication parameters:

  • Target fragment size: 200-500bp

  • Verification of fragmentation by agarose gel electrophoresis

  • Typical conditions: 30 seconds on/30 seconds off, 12-15 cycles at medium power

• Quality control checks:

  • Verify protein immunoprecipitation by Western blot (10% of IP)

  • Check DNA recovery using fluorometric quantification

  • Assess fragment size distribution using Bioanalyzer

• Data validation approaches:

  • Repeat experiments with multiple biological replicates

  • Confirm selected targets by independent methods (e.g., reporter assays)

  • Compare with genomic binding patterns of related proteins

What methodological approaches can distinguish between the enzymatic and structural roles of SPAC23G3.12c?

To differentiate enzymatic versus structural functions:

• Point mutation strategy:

  • Create catalytic triad mutants (e.g., serine to alanine in the active site)

  • Express mutants in SPAC23G3.12c deletion background

  • Compare phenotypes between wild-type, deletion, and catalytic mutants

• Activity-based protein profiling:

  • Use serine protease-specific activity probes

  • Compare labeling in wild-type versus mutant strains

  • Validate with immunoprecipitation using SPAC23G3.12c antibodies

• Protein interaction landscape:

  • Compare protein-protein interactions of wild-type versus catalytically inactive mutants

  • Identify interactions that persist in catalytic mutants (likely structural roles)

  • Detect interactions lost in catalytic mutants (likely dependent on enzymatic activity)

• Protease activity assays:

  • Develop specific fluorogenic substrates for SPAC23G3.12c

  • Measure activity in cellular extracts immunoprecipitated with SPAC23G3.12c antibodies

  • Compare with recombinant protein activity

• Structural biology approaches:

  • Express and purify domains of SPAC23G3.12c for structural studies

  • Use antibodies to verify fold integrity

  • Compare structures with other serine proteases to identify unique features

How can SPAC23G3.12c antibodies be used in studying telomere entanglement resolution?

For telomere entanglement studies:

• Experimental setup:

  • Use taz1Δ mutant cells which develop telomere entanglements

  • Study SPAC23G3.12c localization at different temperatures (19°C vs. 32°C)

  • Compare with known factors involved in entanglement resolution (e.g., Rif1)

• Microscopy approach:

  • Co-immunostaining for RPA (ssDNA marker) and SPAC23G3.12c

  • Focus on cells in anaphase to detect telomere bridges

  • Quantify co-localization of SPAC23G3.12c with RPA-positive structures

• Genetic analysis:

  • Generate taz1Δ SPAC23G3.12cΔ double mutants

  • Compare cold sensitivity phenotypes

  • Assess rescue with catalytic mutants versus wild-type SPAC23G3.12c

• Imaging parameters:

  • Use deconvolution or super-resolution microscopy for detailed localization

  • Apply time-lapse imaging to track dynamics during anaphase progression

  • Quantify aberrant bridge formation and resolution rates

• Biochemical characterization:

  • Perform chromatin fractionation to detect SPAC23G3.12c association with DNA

  • Use nuclear envelope markers to study potential interactions with nuclear pores

  • Investigate association with known telomere entanglement factors

What are the common causes of non-specific binding when using SPAC23G3.12c antibodies and how can they be addressed?

Common non-specific binding issues and solutions:

Additional solutions:

• Pre-absorb antibody with wild-type yeast lysate from related species

• Include 0.1% Tween-20 in antibody dilution buffers to reduce non-specific hydrophobic interactions

• For membrane proteins, optimize detergent types and concentrations in extraction buffers

• Use peptide competition assays to distinguish specific from non-specific signals

How should researchers interpret and address discrepancies between mRNA and protein levels of SPAC23G3.12c?

When facing mRNA-protein level discrepancies:

• Methodological validation:

  • Confirm antibody specificity with knockout controls

  • Verify primer specificity for RT-qPCR

  • Use multiple methodologies to quantify protein (Western blot, mass spectrometry)

• Biological explanations to consider:

  • Post-transcriptional regulation: miRNAs or RNA-binding proteins affecting translation

  • Protein stability differences: Regulated proteolysis or condition-dependent half-life

  • Time-lag effect: Transcription precedes translation by hours

  • Feedback mechanisms: Protein may regulate its own mRNA

• Analysis approaches:

  • Calculate mRNA-protein correlation coefficients under different conditions

  • Compare with known highly correlated genes as positive controls

  • Group by functional pathways (proteins in complexes often show similar behavior)

• Specific patterns observed:

  • Under nitrogen starvation: SPAC23G3.12c mRNA shows significant downregulation (up to -1.11 log values)

  • Protein levels may show different kinetics due to stability or post-translational modifications

  • Functional pathway analysis indicates that mRNA-protein correlation is strong for proteins involved in metabolic processes but more discordant for proteins in complexes

• Experimental designs to address discrepancies:

  • Perform time-course studies to capture dynamics of both mRNA and protein

  • Use translation inhibitors (cycloheximide) or proteasome inhibitors (MG132) to test post-transcriptional regulation

  • Employ ribosome profiling to measure translation efficiency directly