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DDX4 Rabbit mAb

Catalog No.: F1495

Application: Reactivity: Human, Mouse

Usage Information

Dilution
WB1:1000 IP1:100 IF1:200

Application
WB, IP, IF

Reactivity
Human, Mouse

Source
Rabbit

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

Predicted MW
80 kDa

Positive Control	Mouse testes
Negative Control	Mouse brain

Exprimental Methods

WB
Experimental Protocol: Sample preparation 1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail)，and homogenize the tissue at a low temperature. 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/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) and put the sample on ice for 5 min. 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/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) and put the sample on ice for 5 min. 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 5% skim milk powder to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:1000), 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.

Experimental Protocol:

Sample preparation

1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail)，and homogenize the tissue at a low temperature.

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/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) and put the sample on ice for 5 min.

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/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) and put the sample on ice for 5 min.

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 5% skim milk powder to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:1000), 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： Specimen Preparation 1. Aspirate liquid, then cover cells to a depth of 2–3 mm with 4% Paraformaldehyde diluted in 1X PBS. NOTE: Paraformaldehyde is toxic, use only in a fume hood. 2. Fix cells for 15 min at room temperature. 3. Aspirate fixative, rinse three times in 1X PBS for 5 min each. 4. Proceed with Immunostaining. Immunostaining 1. Add theblocking buffer and incubate for 60 min at RT. 2. Prepare primary antibody diluent in antibody dilution buffer as recommended . 3. Aspirate blocking solution, apply diluted primary antibody. 4. Incubate overnight at 4°C. 5. Rinse three times in 1X PBS for 5 min each. 6. Incubate specimens in fluorochrome-conjugated secondary antibody diluted in antibody dilution buffer for 1–2 hr at room temperature in the dark. 7. Rinse three times in 1X PBS for 5 min each. 8. Mount slides usingmounting medium with DAPI and cover with coverslips. 9. For best results, allow mountant to cure overnight at room temperature. For long-term storage, store slides flat at 23°C protected from light.

Experimental Protocol：

Specimen Preparation

1. Aspirate liquid, then cover cells to a depth of 2–3 mm with 4% Paraformaldehyde diluted in 1X PBS.

NOTE: Paraformaldehyde is toxic, use only in a fume hood.

2. Fix cells for 15 min at room temperature.

3. Aspirate fixative, rinse three times in 1X PBS for 5 min each.

4. Proceed with Immunostaining.

Immunostaining

1. Add theblocking buffer and incubate for 60 min at RT.

2. Prepare primary antibody diluent in antibody dilution buffer as recommended .

3. Aspirate blocking solution, apply diluted primary antibody.

4. Incubate overnight at 4°C.

5. Rinse three times in 1X PBS for 5 min each.

6. Incubate specimens in fluorochrome-conjugated secondary antibody diluted in antibody dilution buffer for 1–2 hr at room temperature in the dark.

7. Rinse three times in 1X PBS for 5 min each.

8. Mount slides usingmounting medium with DAPI and cover with coverslips.

9. For best results, allow mountant to cure overnight at room temperature. For long-term storage, store slides flat at 23°C protected from light.

Datasheet & SDS

Biological Description

Specificity
DDX4 Rabbit mAb recognizes endogenous levels of total DDX4 protein.

Subcellular Location
Cytoplasm

Uniprot ID
Q9NQI0

Clone
L3J16

Synonym(s)
DEAD box protein 4, Vasa homolog , Probable ATP-dependent RNA helicase DDX4, VASA

Background
DDX4 (DEAD-box helicase 4), also known as the Drosophila Vasa homolog, is a highly conserved, germline-specific RNA helicase belonging to the DEAD-box protein family, characterized by the conserved Asp-Glu-Ala-Asp (DEAD) motif within motif II and an upstream Q motif. Structurally, DDX4 consists of two RecA-like globular domains connected by a flexible linker, each composed of five β-strands surrounded by five α-helices, forming a helicase core that facilitates ATP binding, hydrolysis, and RNA binding/unwinding. These domains exhibit nine conserved motifs essential for catalytic activity and interaction with RNA and cofactors. The flexible architecture allows conformational changes critical for helicase function, while variable N- and C-terminal extensions mediate interactions with other RNAs or proteins. In germ cells, DDX4 is essential for mRNA translation regulation, piRNA biogenesis, and transposon silencing. Aberrantly, DDX4 is re-expressed in several cancers—including small cell lung cancer (SCLC)—where it enhances cell survival, motility, and chemoresistance by activating DNA repair and immune response pathways, making it a potential therapeutic target.

Background

DDX4 (DEAD-box helicase 4), also known as the Drosophila Vasa homolog, is a highly conserved, germline-specific RNA helicase belonging to the DEAD-box protein family, characterized by the conserved Asp-Glu-Ala-Asp (DEAD) motif within motif II and an upstream Q motif. Structurally, DDX4 consists of two RecA-like globular domains connected by a flexible linker, each composed of five β-strands surrounded by five α-helices, forming a helicase core that facilitates ATP binding, hydrolysis, and RNA binding/unwinding. These domains exhibit nine conserved motifs essential for catalytic activity and interaction with RNA and cofactors. The flexible architecture allows conformational changes critical for helicase function, while variable N- and C-terminal extensions mediate interactions with other RNAs or proteins. In germ cells, DDX4 is essential for mRNA translation regulation, piRNA biogenesis, and transposon silencing. Aberrantly, DDX4 is re-expressed in several cancers—including small cell lung cancer (SCLC)—where it enhances cell survival, motility, and chemoresistance by activating DNA repair and immune response pathways, making it a potential therapeutic target.

References
https://pubmed.ncbi.nlm.nih.gov/36653474/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.

Handling Instructions

Tel: +1-832-582-8158 Ext:3
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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%