PRP31 Antibody

What is PRPF31 and what cellular functions does it serve?

PRPF31 is a component of the spliceosome complex that plays a critical role in pre-mRNA processing. It is recruited to introns following the attachment of U4 and U6 RNAs and the 15.5K protein, making it crucial for the transition of the spliceosomal complex to the activated state . PRPF31 forms an essential connection between the U4/U6 and U5 snRNPs with PRPF6, and is required for tri-snRNP assembly in human cells . Beyond its role in splicing, research has demonstrated that PRPF31 also has direct roles in mitotic chromosome segregation, indicating its multifunctional nature in cellular processes .

What applications can PRPF31 antibodies be utilized for?

PRPF31 antibodies have been validated for multiple experimental applications with specific optimized protocols. Commercial antibodies like the 27750-1-AP can be used in Western Blot (WB), Immunohistochemistry (IHC), Immunofluorescence on paraffin-embedded sections (IF-P), and ELISA applications . These antibodies have been tested and confirmed to show reactivity with both human and mouse samples, making them versatile tools for comparative studies across species . Additionally, custom anti-PRPF31 polyclonal antibodies have been successfully prepared using synthetic peptides corresponding to specific amino acid residues (such as 416-432) for specialized research applications including immunoprecipitation coupled to microarray analysis .

What are the optimal dilutions for PRPF31 antibody across different applications?

The optimal dilution of PRPF31 antibody varies significantly depending on the specific application and sample type. The recommended dilution ranges are:

It is important to note that these are general guidelines, and researchers should titrate the antibody in each specific experimental system to obtain optimal results, as performance can be sample-dependent . Initial validation experiments using a dilution series are strongly recommended to determine the optimal concentration for your specific tissue or cell type.

How should samples be prepared for PRPF31 detection in retinal tissues?

For retinal tissues, specific sample preparation protocols have been optimized for PRPF31 detection. In immunohistochemistry applications with mouse eye tissue, antigen retrieval with TE buffer pH 9.0 is recommended for optimal results . Alternatively, antigen retrieval may be performed with citrate buffer pH 6.0 if TE buffer yields suboptimal staining. For immunofluorescence on paraffin-embedded sections, similar antigen retrieval methods should be employed, followed by blocking with appropriate serum to minimize background staining. These specific methods have been validated to produce consistent detection of PRPF31 in retinal tissues, which is crucial for studies investigating its role in retinitis pigmentosa pathogenesis .

How can PRPF31 antibody be used to investigate splicing defects?

PRPF31 antibodies can be employed to investigate splicing defects through several methodological approaches. One effective method involves using the antibody in co-transfection experiments with minigenes of retina-specific transcripts. Previous research has demonstrated that expression of mutant PRPF31 proteins inhibits pre-mRNA splicing of specific genes expressed in photoreceptor cells, such as RDS and FSCN2 .

To conduct such experiments, researchers can:

• Create expression vectors containing wild-type or mutant PRPF31 cDNA

• Co-transfect these with minigenes containing retina-specific exons and introns

• Extract RNA and analyze splicing patterns through RT-PCR

• Use Western blotting with PRPF31 antibody to confirm expression of the transfected constructs

This approach has revealed that mutations in PRPF31 significantly inhibit pre-mRNA splicing of intron 3 in the rhodopsin gene and lead to reduced total rhodopsin expression in primary retinal cell cultures .

What is the relationship between PRPF31 and retinitis pigmentosa?

PRPF31 mutations represent the second most common genetic cause of autosomal dominant retinitis pigmentosa (adRP) in most populations worldwide, accounting for approximately 5.5-8.9% of cases in the US, 7.6-8.1% in Spanish populations, and up to 14.1% in Japanese populations .

The disease mechanism involves haploinsufficiency, where reduced levels of PRPF31 expression from the mutated allele result in disease manifestation. Interestingly, PRPF31-related RP exhibits incomplete penetrance with an "all or none" pattern - some mutation carriers develop RP while others remain asymptomatic their entire lives . This incomplete penetrance appears to be related to varying expression levels of the wild-type PRPF31 allele, which can differ by approximately 5-fold between individuals following a continuous distribution .

Genetic modifiers like the MSR1 minisatellite repeat element located upstream of the PRPF31 promoter and the CNOT3 gene may influence expression levels and disease penetrance .

How can I verify PRPF31 antibody specificity in my experiments?

Verifying PRPF31 antibody specificity is crucial for obtaining reliable experimental results. A robust validation approach includes:

• RNAi validation: Perform RNAi-mediated depletion of PRPF31 using dsRNAs targeting the coding regions, then use Western blotting to confirm significant reduction of the PRPF31 band (expected molecular weight: 55-65 kDa) .

• Molecular weight confirmation: The expected molecular weight of PRPF31 is 55 kDa based on commercial antibody validation, which should be confirmed in your experimental system .

• Positive control samples: Include validated positive controls such as A549 cells, Caco-2 cells, HeLa cells, or Jurkat cells, which have been confirmed to express detectable levels of PRPF31 .

• Blocking peptide competition: Use the immunizing peptide (if available) in a competition assay to confirm binding specificity.

• Multiple antibody validation: When possible, confirm key findings using alternative antibodies targeting different epitopes of PRPF31.

For critical experiments, it is advised to only examine cytological consequences of PRPF31 depletion in cell populations where the protein has been reduced to at least 20% of control level, as verified by quantitative Western blotting .

How can PRPF31 antibody be used for immunoprecipitation-coupled microarray analysis?

The immunoprecipitation-coupled microarray approach has been successfully employed to identify RNA transcripts associated with PRPF31-containing splicing complexes. The detailed methodology involves:

• Sample preparation: Prepare cell lysates from mouse retinae in appropriate buffer conditions that preserve RNA-protein interactions.

• Immunoprecipitation: Use affinity-purified polyclonal anti-PRPF31 antibody for immunoprecipitation, with pre-immune Ig preparations as negative controls.

• RNA extraction: Following immunoprecipitation, extract RNAs from the immunoprecipitated RNA-protein complexes using optimized protocols that minimize RNA degradation.

• Microarray analysis: Perform microarray analysis to identify RNA species associated with the PRPF31-containing splicing complexes.

This approach has successfully identified 146 genes detected in samples immunoprecipitated using PRPF31 antibody but not in those prepared using control pre-immune antibodies . Among the identified potential target genes were several retina-specific genes involved in phototransduction (rhodopsin, β-subunit of cGMP phosphodiesterases), the visual cycle (photoreceptor ATP-binding cassette transporter, cellular retinaldehyde binding protein), photoreceptor structure, transcription factors, and other genes important for photoreceptor survival and function .

What methodological approaches can be used to study the dual role of PRPF31 in splicing and mitotic chromosome segregation?

PRPF31's dual role in splicing and mitotic chromosome segregation requires sophisticated experimental approaches to distinguish between direct mitotic effects and indirect consequences of splicing defects. Methodological approaches include:

• RNAi-mediated depletion with rescue experiments: Deplete endogenous PRPF31 using RNAi and then express RNAi-resistant wild-type or mutant PRPF31 to assess rescue of specific phenotypes.

• Protein domain analysis: Express specific domains of PRPF31 to determine which regions are responsible for splicing functions versus mitotic functions.

• Cell cycle synchronization: Synchronize cells at specific cell cycle phases to examine PRPF31 localization and function specifically during mitosis versus interphase.

• Immunofluorescence microscopy: Use dual-labeling approaches with PRPF31 antibody and markers of mitotic structures to analyze PRPF31 localization during different mitotic stages.

• Live cell imaging: Combine PRPF31 antibody staining with live cell imaging to track dynamic changes in PRPF31 localization throughout the cell cycle.

These approaches have helped demonstrate that PRPF31 has direct roles in mitotic chromosome segregation independent of its splicing functions, revealing its multifunctional nature in cellular processes .

How can PRPF31 antibodies contribute to therapy development for PRPF31-related retinitis pigmentosa?

PRPF31 antibodies play vital roles in the development of therapies for PRPF31-related retinitis pigmentosa (PRPF31-RP) through several methodological applications:

• Model system validation: PRPF31 antibodies are essential for validating disease models of PRPF31-RP, including those in yeast, zebrafish, drosophila, rodents, human cells, induced pluripotent stem cells (iPSCs), and retinal organoids .

• Therapeutic target identification: Using immunoprecipitation with PRPF31 antibodies followed by downstream analysis has identified 146 RNA transcripts associated with PRPF31-containing complexes, including several known adRP genes like peripherin/RDS . These represent potential therapeutic targets.

• Gene therapy development: In AAV-mediated gene augmentation approaches, PRPF31 antibodies are crucial for confirming expression of the delivered wild-type PRPF31 gene and assessing restoration of normal splicing activity.

• Therapeutic efficacy assessment: Following experimental therapies, PRPF31 antibodies can be used to evaluate restoration of normal PRPF31 levels and localization, particularly in retinal cells.

• Biomarker development: PRPF31 antibodies may help identify biomarkers for disease progression and treatment response by detecting changes in PRPF31-associated splicing complexes or downstream targets.

These applications highlight how PRPF31 antibodies serve as essential tools in addressing the unmet clinical need for PRPF31-RP treatments .

What are optimal protocols for detecting PRPF31 in patient-derived iPSCs and retinal organoids?

Detecting PRPF31 in patient-derived iPSCs and retinal organoids requires specialized protocols optimized for these complex 3D culture systems:

• Sample preparation for iPSCs:

  • For Western blot: Lyse cells in RIPA buffer supplemented with protease inhibitors

  • For immunofluorescence: Fix cells with 4% paraformaldehyde for 15 minutes at room temperature

• Sample preparation for retinal organoids:

  • For sections: Fix organoids in 4% paraformaldehyde, embed in OCT, and cryosection at 10-12μm

  • For whole-mount: Fix organoids and perform extended permeabilization (0.5% Triton X-100 for 30-60 minutes)

• Antigen retrieval for retinal organoids: Use TE buffer pH 9.0 with heat-mediated antigen retrieval

• Antibody application:

  • For immunofluorescence: Use PRPF31 antibody at 1:50-1:200 dilution with extended incubation (overnight at 4°C)

  • For Western blot: Use 1:2000-1:5000 dilution

• Detection systems:

  • For immunofluorescence: Use fluorophore-conjugated secondary antibodies with nuclear counterstain

  • For chromogenic detection: Use HRP-conjugated secondary antibodies with DAB or similar substrate

These optimized protocols have been successfully used to detect changes in PRPF31 expression and localization in patient-derived retinal cells, revealing that RPE and retinal organoids from PRPF31 patients show significant mis-splicing of genes involved in pre-mRNA and alternative mRNA splicing via the spliceosome .