Biological Description

Specificity HNRNPF Antibody (Mouse mAb) [C13B21] detects endogenous levels of total HNRNPF protein.
Background HNRNPF is a ubiquitously expressed member of the hnRNP F/H family of nuclear RNA‑binding proteins that contribute to early pre‑mRNA processing, and it contains three RNA recognition motifs that bind G‑rich elements and G‑quadruplex‑forming sequences in introns and 3′UTRs to regulate alternative splicing and RNA maturation. The tandem RRMs provide high‑affinity, sequence‑specific recognition of G tracts, while flexible linkers and low‑complexity regions support multivalent interactions with RNA and other splicing factors, positioning HNRNPF within hnRNP complexes that assemble on nascent transcripts and shape splice‑site choice before export to the cytoplasm. Mechanistic studies show that HNRNPF enhances or represses exon inclusion depending on the density, length and proximity of intronic G tracts to the 5′ splice site: G‑quadruplex‑forming motifs bound by HNRNPF promote inclusion of cassette exons, whereas different configurations of G tracts can correlate with exon skipping, indicating that local RNA secondary structure and G‑tract architecture direct HNRNPF’s splicing outcome at individual exons. Genome‑wide profiling in oligodendrocyte lineage cells demonstrates that hnRNPF and its paralog HNRNPH regulate multiple classes of alternative splicing events and also modulate expression of about 6% of genes, including key regulators of the transition from oligodendrocyte progenitors to mature oligodendrocytes, with depletion of hnRNPF/H shifting the transcriptome toward differentiation‑inducing regulators and away from negative controls of maturation. In regulatory T cells, HNRNPF interacts directly with the transcription factor FOXP3, and this complex controls alternative splicing of FOXP3 target genes involved in immune regulation; perturbation of the FOXP3–hnRNPF interaction alters splicing patterns and impacts Treg function, placing HNRNPF at the interface between transcriptional and post‑transcriptional control in immune homeostasis. In embryonic stem cells, ERK signaling phosphorylates HNRNPF and promotes its nuclear activity, supporting self‑renewal and proliferation while suppressing differentiation by influencing splicing of genes in MEK/ERK pathways, which links extracellular growth signals to hnRNPF‑mediated control of developmental gene programs. Cancer‑focused analyses show that HNRNPF participates in MYC‑dependent splicing regulation: hnRNPF and hnRNPH activate inclusion of a MYC‑regulated HRAS cassette exon via binding to downstream G‑rich cis‑elements, and loss of hnRNPF/H alters cell‑cycle progression and induces apoptosis in prostate cancer cells, indicating that HNRNPF‑directed splicing of HRAS and other targets contributes to oncogenic signaling and tumor cell viability. Pan‑cancer transcriptomic work further implicates HNRNPF in pathways such as G2/M checkpoint, DNA repair, IL6/JAK/STAT3 signaling and mitotic spindle organization, and shows that HNRNPF expression correlates with immune cell infiltration and has tumor‑type‑specific prognostic associations, with higher hnRNP family expression linked to poor outcomes in some cancers and better survival in others, consistent with context‑dependent roles of hnRNPF‑regulated splicing in tumor biology and immune interactions.

Usage Information

Application WB, IF Dilution
WB IF
1:5000-1:50000 1:50-1:500
Reactivity Mouse, Rat, Human
Source Mouse Monoclonal Antibody MW 46 kDa
Storage Buffer PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3
Storage
(from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years
WB
Experimental Protocol:
 
Sample preparation
1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/Nuclear Lysis Buffer (containing Protease Inhibitor Cocktail),and homogenize the tissue at a low temperature or lyse it by sonication on ice, then incubate on ice for 30 minutes.
2. Adherent cell: Aspirate the culture medium and wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/Nuclear Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes.
3. Suspension cell: Transfer the culture medium to a pre-cooled centrifuge tube. Centrifuge and aspirate the supernatant. Wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/Nuclear Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes.
4. Place the lysate into a pre-cooled microcentrifuge tube. Centrifuge at 4°C for 15 min. Collect the supernatant;
5. Remove a small volume of lysate to determine the protein concentration;
6. Combine the lysate with protein loading buffer. Boil 20 µL sample under 95-100°C for 5 min. Centrifuge for 5 min after cool down on ice.
 
Electrophoretic separation
1. According to the concentration of extracted protein, load appropriate amount of protein sample and marker onto SDS-PAGE gels for electrophoresis. Recommended separating gel (lower gel) concentration: 10%. Reference Table for Selecting SDS-PAGE Separation Gel Concentrations
2. Power up 80V for 30 minutes. Then the power supply is adjusted (110 V~150 V), the Marker is observed, and the electrophoresis can be stopped when the indicator band of the predyed protein Marker where the protein is located is properly separated. (Note that the current should not be too large when electrophoresis, too large current (more than 150 mA) will cause the temperature to rise, affecting the result of running glue. If high currents cannot be avoided, an ice bath can be used to cool the bath.)
 
Transfer membrane
1. Take out the converter, soak the clip and consumables in the pre-cooled converter;
2. Activate PVDF membrane with methanol for 1 min and rinse with transfer buffer;
3. Install it in the order of "black edge of clip - sponge - filter paper - filter paper - glue -PVDF membrane - filter paper - filter paper - sponge - white edge of clip";
4. The protein was electrotransferred to PVDF membrane. ( 0.45 µm PVDF membrane is recommended ) Reference Table for Selecting PVDF Membrane Pore Size Specifications
Recommended conditions for wet transfer: 200 mA, 120 min.
( Note that the transfer conditions can be adjusted according to the protein size. For high-molecular-weight proteins, a higher current and longer transfer time are recommended. However, ensure that the transfer tank remains at a low temperature to prevent gel melting.)
 
Block
1. After electrotransfer, wash the film with TBST at room temperature for 5 minutes;
2. Incubate the film in the blocking solution for 1 hour at room temperature;
3. Wash the film with TBST for 3 times, 5 minutes each time.
 
Antibody incubation
1. Use primary antibody dilution buffer to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:5000), gently shake and incubate with the film at 4°C overnight;
2. Wash the film with TBST 3 times, 5 minutes each time;
3. Add the secondary antibody to the blocking solution and incubate with the film gently at room temperature for 1 hour;
4. After incubation, wash the film with TBST 3 times for 5 minutes each time.
 
Antibody staining
1. Add the prepared ECL luminescent substrate (or select other color developing substrate according to the second antibody) and mix evenly;
2. Incubate with the film for 1 minute, remove excess substrate (keep the film moist), wrap with plastic film, and expose in the imaging system.
IF
Experimental Protocol:
 
Sample Preparation
1. Adherent Cells: Place a clean, sterile coverslip in a culture dish. Once the cells grow to near confluence as a monolayer, remove the coverslip for further use.
2. Suspension Cells: Seed the cells onto a clean, sterile slide coated with poly-L-lysine.
3. Frozen Sections: Allow the slide to thaw at room temperature. Wash it with pure water or PBS for 2 times, 3 minutes each time.
4. Paraffin Sections: Deparaffinization and rehydration. Wash the slide with pure water or PBS for 3 times, 3 minutes each time. Then perform antigen retrieval.
 
Fixation
1. Fix the cell coverslips/spots or tissue sections at room temperature using a fixative such as 4% paraformaldehyde (4% PFA) for 10-15 minutes.
2. Wash the sample with PBS for 3 times, 3 minutes each time.
 
Permeabilization
1.Add a detergent such as 0.1–0.3% Triton X-100 to the sample and incubate at room temperature for 10–20 minutes.
(Note: This step is only required for intracellular antigens. For antigens expressed on the cell membrane, this step is unnecessary.)
Wash the sample with PBS for 3 times, 3 minutes each time.
 
Blocking
Add blocking solution and incubate at room temperature for at least 1 hour. (Common blocking solutions include: serum from the same source as the secondary antibody, BSA, or goat serum.)
Note: Ensure the sample remains moist during and after the blocking step to prevent drying, which can lead to high background.
 
Immunofluorescence Staining (Day 1)
1. Remove the blocking solution and add the diluted primary antibody.
2. Incubate the sample in a humidified chamber at 4°C overnight.
 
Immunofluorescence Staining (Day 2)
1. Remove the primary antibody and wash with PBST for 3 times, 5 minutes each time.
2. Add the diluted fluorescent secondary antibody and incubate in the dark at 4°C for 1–2 hours.
3. Remove the secondary antibody and wash with PBST for 3 times, 5 minutes each time.
4. Add diluted DAPI and incubate at room temperature in the dark for 5–10 minutes.
5. Wash with PBST for 3 times, 5 minutes each time.
 
Mounting
1. Mount the sample with an anti-fade mounting medium.
2. Allow the slide to dry at room temperature overnight in the dark.
3. Store the slide in a slide storage box at 4°C, protected from light.
 

References

  • https://pubmed.ncbi.nlm.nih.gov/29269483/
  • https://pubmed.ncbi.nlm.nih.gov/23284676/

Application Data

WB

Validated by Selleck

  • F5133-wb
    Lane 1: LNCaP, Lane 2: NIH/3T3, Lane 3: Hela, Lane 4: K562