EXOSC8 Antibody

What is EXOSC8 and what is its function in cellular RNA metabolism?

EXOSC8 is a non-catalytic component of the RNA exosome complex that possesses 3'→5' exoribonuclease activity. This protein participates in numerous cellular RNA processing and degradation events across different cellular compartments:

• Nuclear functions: EXOSC8 contributes to proper maturation of stable RNA species (rRNA, snRNA, snoRNA), elimination of RNA processing by-products, non-coding "pervasive" transcripts, and mRNAs with processing defects .

• Cytoplasmic functions: EXOSC8 participates in general mRNA turnover, specifically targeting inherently unstable mRNAs containing AU-rich elements (AREs) within 3' untranslated regions. It also functions in RNA surveillance pathways that prevent translation of aberrant mRNAs and appears involved in histone mRNA degradation .

The catalytically inactive RNA exosome core complex (Exo-9), which includes EXOSC8, plays a pivotal role in binding and presenting RNA for ribonucleolysis, serving as a scaffold for association with catalytic subunits and accessory proteins or complexes .

What applications can EXOSC8 antibodies be reliably used for?

Based on validated commercial antibodies, EXOSC8 antibodies can be successfully employed in multiple experimental applications:

When selecting an antibody, researchers should consider the specific host species (rabbit polyclonal vs. mouse monoclonal) and reactivity with human, mouse, or other species of interest .

What are the properties and alternative designations for EXOSC8?

EXOSC8 is identified by multiple aliases in scientific literature and databases:

• Alternative names: CIP3, EAP2, OIP2, PCH1C, RRP43, Rrp43p, bA421P11.3, p9, OIP-2

• Molecular weight: 30 kDa (calculated from 276 amino acids), observed at 30-35 kDa in Western blots

• Gene ID (NCBI): 11340

• UniProt ID: Q96B26

• GenBank Accession Number: BC020773

The protein sequence for human EXOSC8 begins with: MAAGFKTVEPLEYYRRFLKENCRPDGRELGEF...

How does EXOSC8 specifically regulate ARE-containing mRNAs in the context of myelin development?

Research has shown that EXOSC8 plays a critical role in regulating mRNAs containing AU-rich elements (AREs), particularly those involved in myelin development. Experimental evidence demonstrates:

• Downregulation of EXOSC8 in human oligodendroglia cells (MO3.13) leads to a dramatic increase (>100-fold, P=0.013) in myelin basic protein (MBP) mRNA expression .

• This increase in MBP mRNA translates to elevated MBP protein levels in differentiated oligodendroglia cells, as confirmed by both immunostaining and immunoblotting .

• EXOSC8 knockdown in myoblasts significantly increases expression of multiple ARE-containing myelin-related genes, including MBP (>6.5-fold, P=0.0167) and myelin-associated oligodendrocyte basic protein (MOBP) (>8.5-fold, P=0.0158) .

• Patient fibroblasts with EXOSC8 mutations show significantly increased expression of SMN1 (~4-fold, P=0.01984), a gene associated with spinal muscular atrophy .

These findings suggest EXOSC8 normally functions to regulate the turnover of specific ARE-containing transcripts critical for myelin formation and motor neuron function, explaining why EXOSC8 mutations lead to hypomyelination and neurological disorders .

What is the relationship between EXOSC8 function and erythroid development?

EXOSC8 appears to play a regulatory role in erythroid development through transcriptional regulation:

• GATA-1, a master regulator of erythropoiesis, represses EXOSC8 expression approximately 25-fold during erythroid maturation .

• Foxo3 occupies the EXOSC8 promoter, and knocking down Foxo3 de-represses EXOSC8 expression three-fold, suggesting direct transcriptional regulation .

• In primary human erythroblasts, both GATA-1 and Foxo3 occupy the EXOSC8 promoter .

• Knockdown of EXOSC8 enhances expression of several GATA-1-activated erythroid genes (Hbb-b1, Alas2, and Slc4a1) by three- to 12-fold, while other GATA-1-activated genes (Epb4.9 and Fog-1) remain largely unaffected .

• This regulation appears to involve transcriptional mechanisms beyond simple mRNA degradation, as primary unprocessed transcripts for EXOSC8-responsive genes also increase two- to seven-fold upon EXOSC8 knockdown .

These findings suggest EXOSC8 functions as part of a regulatory circuit that fine-tunes gene expression during erythroid differentiation.

What are the optimal conditions for validating EXOSC8 antibody specificity?

Rigorous validation of EXOSC8 antibody specificity requires multiple complementary approaches:

• siRNA knockdown validation:

  • Transfect target-specific siRNA probes into appropriate cell lines (e.g., U-2 OS human bone osteosarcoma cells)

  • Include a control siRNA transfection

  • Perform Western blot with the EXOSC8 antibody to confirm decreased signal intensity in knockdown samples compared to control

• Cell/tissue type selection for positive controls:

  • Human cell lines: HEK-293, HeLa

  • Human tissues: Brain, colon

• Antibody dilution optimization:

  • Western Blot: 1:500-1:2000

  • Immunohistochemistry: 1:800-1:3200

  • Immunofluorescence: 1:20-1:200

• Antigen retrieval for IHC:

  • Primary method: TE buffer pH 9.0

  • Alternative method: Citrate buffer pH 6.0

• Negative controls:

  • Secondary antibody only

  • Isotype control antibody

  • Antibody pre-absorbed with immunizing peptide

What are the methodological considerations when studying EXOSC8 mutations in neurological disease models?

When investigating EXOSC8 mutations in neurological disease models, researchers should consider:

• Model system selection:

  • Patient-derived fibroblasts can reveal alterations in ARE-containing mRNA levels

  • Zebrafish has been used successfully to model EXOSC8 deficiency and study myelin disruption

  • Human oligodendroglia cell lines (e.g., MO3.13) are valuable for studying effects on myelin protein expression

• mRNA analysis approach:

  • Select both ARE-containing and non-ARE-containing transcripts for comparison

  • Use qRT-PCR to analyze expression changes in:

    • Myelin-related transcripts (MBP, MOBP)

    • Motor neuron-related transcripts (SMN1)

    • Control non-ARE transcripts

• Protein-level verification:

  • Confirm mRNA changes translate to protein-level alterations using immunoblotting and immunostaining

  • Analyze cellular localization of affected proteins

• Nonsense-mediated decay investigation:

  • For potential nonsense mutations, treat cells with puromycin (300 mM) to inhibit nonsense-mediated decay

  • Compare mutant transcript levels before and after treatment

• Functional consequences assessment:

  • Evaluate myelin formation in relevant models

  • Assess motor neuron function in animal models

  • Correlate molecular findings with clinical presentations of cerebellar hypoplasia, abnormal myelination, and motor neuron disease

How can flow cytometry be optimized for studying EXOSC8's role in cell differentiation?

When using flow cytometry to study EXOSC8's role in cellular differentiation processes:

• Sample preparation protocol:

  • Wash cells with PBS

  • Use 1 × 10^6 cells per sample

  • Stain with appropriate lineage markers (e.g., Ter119-APC and CD71-PE for erythroid cells)

  • Incubate at 4°C for 30 minutes in the dark

  • Wash 3 times with 2% bovine serum albumin in PBS

• Cell population discrimination:

  • Use DAPI staining to exclude dead cells

  • For shRNA knockdown studies, use GFP co-expression as a marker for transduced cells

• Cell cycle analysis:

  • Resuspend cells at 5 × 10^6 cells/ml

  • Further process according to standard cell cycle analysis protocols

• Gating strategy:

  • First gate on live cells (DAPI negative)

  • For erythroid differentiation studies, gate on Ter119 and CD71 expression profiles to identify developmental stages (R1, R2, R3, R4/5)

  • For shRNA-expressing cells, gate on GFP-positive population

• Controls:

  • Include unstained controls

  • Include single-color controls for compensation

  • Include both knockdown and control shRNA samples

What are the key considerations when planning EXOSC8 knockdown experiments?

When designing EXOSC8 knockdown experiments:

• Knockdown method selection:

  • siRNA for transient knockdown (easier but shorter term)

  • shRNA for stable knockdown (requires selection but provides long-term suppression)

• Cell type selection based on research question:

  • Myoblasts for muscle-related studies

  • Fibroblasts for general cellular functions or patient-derived studies

  • Oligodendroglia cells (MO3.13) for myelin-related investigations

  • Erythroid precursor cells for studying erythropoiesis

• Target gene selection for analysis:

  • ARE-containing mRNAs: Search the ARE Database (ARED) for relevant candidates

  • Include both ARE-containing and non-ARE-containing transcripts as controls

  • Focus on tissue-specific transcripts relevant to the biological process under study

• Downstream analysis:

  • qRT-PCR for mRNA level changes

  • Western blot for protein level changes

  • Cell differentiation assays for functional consequences

  • Specialized assays based on cell type (e.g., myelin formation assays)

• Controls and validation:

  • Include non-targeting control siRNA/shRNA

  • Verify knockdown efficiency by qRT-PCR and Western blot

  • Rescue experiments with wild-type EXOSC8 to confirm specificity of effects

How should researchers interpret conflicting results when studying EXOSC8 in different cell types?

When faced with conflicting results across different cell types:

• Recognize cell type-specific functions:

  • EXOSC8 regulates different ARE-containing mRNAs in different cell types

  • In myoblasts and oligodendroglia cells, MBP and MOBP are strongly affected

  • In fibroblasts, SMN1 shows significant changes

  • Other tested ARE-containing mRNAs may show no significant changes in specific cell types

• Consider regulatory context:

  • The availability of cell type-specific transcription factors (e.g., GATA-1, Foxo3 in erythroid cells) affects EXOSC8 expression and function

  • Different cell types may have different exosome complex compositions or cofactors

• Examine expression levels:

  • Baseline expression of EXOSC8 varies across tissues

  • The impact of partial knockdown may vary depending on baseline expression levels

• Technical considerations:

  • Knockdown efficiency may vary between cell types

  • Antibody performance may differ in different cellular contexts

  • Cell culture conditions can influence results

• Integrated analysis approach:

  • Compare multiple parameters (mRNA levels, protein levels, functional outcomes)

  • Consider both direct and indirect effects of EXOSC8 disruption

  • Relate findings to known physiological functions of each cell type

What is the optimal protein extraction protocol for detecting EXOSC8 in Western blot applications?

For optimal EXOSC8 detection by Western blot:

• Lysis buffer composition:

  • Use RIPA buffer supplemented with protease inhibitors for general applications

  • For nuclear/cytoplasmic fractionation (as EXOSC8 functions in both compartments), use specialized fractionation buffers

• Sample processing:

  • Keep samples on ice during processing

  • Use sonication to ensure complete lysis and shearing of genomic DNA

  • Centrifuge at 14,000g for 15 minutes at 4°C to remove cellular debris

• Protein quantification:

  • Use BCA or Bradford assay to normalize protein loading

  • Typically load 20-40 μg of total protein per lane

• Gel electrophoresis conditions:

  • Use 10-12% SDS-PAGE gels (EXOSC8 is approximately 30 kDa)

  • Include positive control samples (HEK-293 or HeLa cell lysates)

• Antibody dilution and incubation:

  • Primary antibody: 1:500-1:2000 dilution

  • Incubate overnight at 4°C for optimal results

  • Secondary antibody: Follow manufacturer's recommendations, typically 1:2000-1:10000

  • Expected band size: 30-35 kDa

• Signal detection:

  • Enhanced chemiluminescence (ECL) is typically sufficient

  • For weak signals, consider more sensitive detection systems or longer exposure times

What are the most effective methods for analyzing EXOSC8's interaction with specific ARE-containing mRNAs?

To effectively analyze EXOSC8 interactions with specific ARE-containing mRNAs:

• RNA-Immunoprecipitation (RIP):

  • Cross-link RNA-protein complexes with formaldehyde

  • Immunoprecipitate with anti-EXOSC8 antibody

  • Extract RNA from immunoprecipitated complexes

  • Perform qRT-PCR for candidate ARE-containing mRNAs or RNA-seq for global analysis

• CLIP (Cross-linking and immunoprecipitation):

  • UV cross-linking provides more specific RNA-protein interactions

  • Immunoprecipitate with anti-EXOSC8 antibody

  • Sequence bound RNAs to identify binding sites and motifs

• Reporter assays:

  • Clone ARE-containing 3'UTRs downstream of a luciferase reporter

  • Compare reporter activity with and without EXOSC8 knockdown

  • Mutate ARE sequences to confirm specificity

• mRNA stability assays:

  • Treat cells with actinomycin D to block transcription

  • Harvest RNA at different time points

  • Measure decay rates of ARE-containing mRNAs in control versus EXOSC8-depleted cells

  • Calculate half-life of specific transcripts

• In silico analysis:

  • Use the ARE Database (ARED) to identify potential EXOSC8 targets

  • Search for enrichment of specific ARE motifs in affected transcripts

  • Compare with known EXOSC8-regulated mRNAs (MBP, MOBP, SMN1)

How can researchers effectively optimize immunohistochemistry protocols for EXOSC8 detection in different tissue types?

For optimal EXOSC8 detection by immunohistochemistry across tissue types:

• Fixation method:

  • Formalin fixation and paraffin embedding is standard

  • Fixation time should be optimized (typically 24-48 hours)

  • Over-fixation can mask epitopes

• Antigen retrieval optimization:

  • Primary recommendation: Heat-mediated antigen retrieval with citrate buffer pH 6.0

  • Alternative method: TE buffer pH 9.0

  • Optimization of retrieval time (typically 10-20 minutes)

• Antibody dilution titration:

  • Start with manufacturer's recommended range (typically 1:800-1:3200)

  • Perform dilution series to determine optimal signal-to-noise ratio

  • Include positive control tissue (human colon or Fallopian tube)

• Signal detection system selection:

  • DAB (3,3'-diaminobenzidine) for brightfield microscopy

  • Fluorescent secondary antibodies for co-localization studies

  • Consider amplification systems for weak signals

• Counterstaining considerations:

  • Hematoxylin for nuclear counterstaining in brightfield

  • DAPI for nuclear counterstaining in fluorescence

  • Adjust counterstaining intensity based on EXOSC8 signal strength

• Tissue-specific considerations:

  • Human Fallopian tube tissue shows EXOSC8 in cytoplasm and membrane of glandular cells

  • Different tissues may require adjusted antibody concentrations or detection methods

How can EXOSC8 antibodies be utilized to study its role in neurodegenerative disease mechanisms?

EXOSC8 antibodies can be strategically employed to investigate neurodegenerative disease mechanisms:

• Patient tissue analysis:

  • Compare EXOSC8 expression and localization in post-mortem brain tissues from patients with neurodegenerative disorders versus controls

  • Focus on regions showing hypomyelination, cerebellar hypoplasia, or motor neuron pathology

• Cell type-specific expression analysis:

  • Use dual immunofluorescence with cell type-specific markers to determine EXOSC8 expression in:

    • Oligodendrocytes (myelin-producing cells)

    • Motor neurons

    • Cerebellar neurons

    • Support cells (astrocytes, microglia)

• Patient-derived cell studies:

  • Generate induced pluripotent stem cells (iPSCs) from patients with EXOSC8 mutations

  • Differentiate into neurons, oligodendrocytes, or motor neurons

  • Analyze EXOSC8 expression, localization, and associated mRNA metabolism defects

• Animal model validation:

  • Use EXOSC8 antibodies to confirm knockdown/knockout efficiency in zebrafish or mouse models

  • Correlate EXOSC8 levels with pathological features

  • Track developmental and disease progression in relation to EXOSC8 expression

• Therapeutic approach assessment:

  • Monitor EXOSC8 expression and function in response to potential therapeutic interventions

  • Use EXOSC8 antibodies to assess restoration of normal protein levels or localization

What approaches are recommended for investigating EXOSC8's function in the exosome complex versus its potential independent roles?

To distinguish between EXOSC8's functions within the exosome complex and potential independent roles:

• Co-immunoprecipitation studies:

  • Use anti-EXOSC8 antibodies to pull down the protein and associated factors

  • Identify interaction partners by mass spectrometry

  • Compare interactome between different cell types or disease states

  • Look for non-exosomal protein interactions

• Proximity labeling approaches:

  • Express EXOSC8 fused to a proximity labeling enzyme (BioID, APEX)

  • Identify proteins in close proximity to EXOSC8 in living cells

  • Compare with known exosome complex components

• Sub-cellular fractionation:

  • Separate nuclear, cytoplasmic, and membrane fractions

  • Analyze EXOSC8 distribution across fractions

  • Compare with distribution of other exosome components

  • Look for fractions where EXOSC8 is present but other exosome components are absent

• Differential knockdown experiments:

  • Compare phenotypes between EXOSC8 knockdown and knockdown of other exosome components

  • Identify EXOSC8-specific effects versus general exosome disruption effects

  • Perform rescue experiments with mutant EXOSC8 that cannot incorporate into the exosome complex

• Structural studies:

  • Use antibodies for epitope mapping

  • Identify domains required for exosome complex incorporation versus potential independent functions

  • Develop domain-specific antibodies to distinguish different functional pools of EXOSC8