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MCM3 Rabbit mAb

Catalog No.: F3650

Application: Reactivity: Human, Mouse, Rat

Usage Information

Dilution
WB1:1000 - 1:10000 IHC1:100 - 1:250 FCM1ug/ml

Application
WB, IHC, FCM

Reactivity
Human, Mouse, Rat

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
91 kDa

Positive Control	Normal colon tissue; Human colon tissue; Human tonsil tissue; Breast carcinoma tissue; Normal brain tissue; Lung carcinoma tissue; Cervical carcinoma tissue; L6 cell; C6 cell; RAW 264.7 cell; PC-12 cell; NIH/3T3 cell; HeLa cell; K562 cell; HepG2 cell; U937 cell; 293T cell
Negative Control

Exprimental Methods

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. 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) 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/Nuclear 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/Nuclear 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/Nuclear 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/Nuclear 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.

IHC
Experimental Protocol： Deparaffinization/Rehydration 1. Deparaffinize/hydrate sections: 2. Incubate sections in three washes of xylene for 5 min each. 3. Incubate sections in two washes of 100% ethanol for 10 min each. 4. Incubate sections in two washes of 95% ethanol for 10 min each. 5. Wash sections two times in dH2O for 5 min each. 6.Antigen retrieval: For Citrate: Heat slides in a microwave submersed in 1X citrate unmasking solution until boiling is initiated; continue with 10 min at a sub-boiling temperature (95°-98°C). Cool slides on bench top for 30 min. Staining 1. Wash sections in dH2O three times for 5 min each. 2. Incubate sections in 3% hydrogen peroxide for 10 min. 3. Wash sections in dH2O two times for 5 min each. 4. Wash sections in wash buffer for 5 min. 5. Block each section with 100–400 µl of blocking solution for 1 hr at room temperature. 6. Remove blocking solution and add 100–400 µl primary antibody diluent in to each section. Incubate overnight at 4°C. 7. Remove antibody solution and wash sections with wash buffer three times for 5 min each. 8. Cover section with 1–3 drops HRPas needed. Incubate in a humidified chamber for 30 min at room temperature. 9. Wash sections three times with wash buffer for 5 min each. 10. Add DAB Chromogen Concentrate to DAB Diluent and mix well before use. 11. Apply 100–400 µl DAB to each section and monitor closely. 1–10 min generally provides an acceptable staining intensity. 12. Immerse slides in dH2O. 13. If desired, counterstain sections with hematoxylin. 14. Wash sections in dH2O two times for 5 min each. 15. Dehydrate sections: Incubate sections in 95% ethanol two times for 10 sec each; Repeat in 100% ethanol, incubating sections two times for 10 sec each; Repeat in xylene, incubating sections two times for 10 sec each. 16. Mount sections with coverslips and mounting medium.

IHC

Experimental Protocol：

Deparaffinization/Rehydration

1. Deparaffinize/hydrate sections:

2. Incubate sections in three washes of xylene for 5 min each.

3. Incubate sections in two washes of 100% ethanol for 10 min each.

4. Incubate sections in two washes of 95% ethanol for 10 min each.

5. Wash sections two times in dH2O for 5 min each.

6.Antigen retrieval: For Citrate: Heat slides in a microwave submersed in 1X citrate unmasking solution until boiling is initiated; continue with 10 min at a sub-boiling temperature (95°-98°C). Cool slides on bench top for 30 min.

Staining

1. Wash sections in dH2O three times for 5 min each.

2. Incubate sections in 3% hydrogen peroxide for 10 min.

3. Wash sections in dH2O two times for 5 min each.

4. Wash sections in wash buffer for 5 min.

5. Block each section with 100–400 µl of blocking solution for 1 hr at room temperature.

6. Remove blocking solution and add 100–400 µl primary antibody diluent in to each section. Incubate overnight at 4°C.

7. Remove antibody solution and wash sections with wash buffer three times for 5 min each.

8. Cover section with 1–3 drops HRPas needed. Incubate in a humidified chamber for 30 min at room temperature.

9. Wash sections three times with wash buffer for 5 min each.

10. Add DAB Chromogen Concentrate to DAB Diluent and mix well before use.

11. Apply 100–400 µl DAB to each section and monitor closely. 1–10 min generally provides an acceptable staining intensity.

12. Immerse slides in dH2O.

13. If desired, counterstain sections with hematoxylin.

14. Wash sections in dH2O two times for 5 min each.

15. Dehydrate sections: Incubate sections in 95% ethanol two times for 10 sec each; Repeat in 100% ethanol, incubating sections two times for 10 sec each; Repeat in xylene, incubating sections two times for 10 sec each.

16. Mount sections with coverslips and mounting medium.

Datasheet & SDS

Biological Description

Specificity
MCM3 Rabbit mAb recognizes endogenous levels of total MCM3 protein.

Subcellular Location
Chromosome, Nucleus

Uniprot ID
P25205

Clone
B16A9

Synonym(s)
DNA replication licensing factor MCM3, DNA polymerase alpha holoenzyme-associated protein P1, P1-MCM3, RLF subunit beta, p102, MCM3

Background
MCM3 is a core subunit of the minichromosome maintenance (MCM) 2–7 complex, which acts as the essential replicative helicase for the initiation and elongation of DNA replication in eukaryotic cells. This large protein, about 971 amino acids, shares significant homology with MCM2, especially in three conserved regions critical for helicase activity and DNA binding. Structurally, MCM3 contains multiple phosphorylation sites and interfaces that mediate interactions with other MCM subunits, particularly MCM5, and is incorporated into the hexameric MCM2-7 ring that loads onto replication origins as part of the pre-replicative complex (pre-RC) during late M and G1 phases. Recruitment of MCM3 to origins depends on the origin recognition complex (ORC), CDC6, and CDT1, ensuring that replication licensing occurs only once per cell cycle. MCM3’s activity is tightly regulated by phosphorylation, notably by cyclin-dependent kinases such as cyclin E/Cdk2, which phosphorylates threonine 722 to promote chromatin loading but can inhibit replication if dysregulated. It is also a substrate for checkpoint kinases ATM and ATR, linking MCM3 to DNA damage responses and replication checkpoint pathways. Acetylation by MCM3AP inhibits DNA replication initiation and cell cycle progression, adding another layer of control. The prolyl isomerase Pin1 modulates MCM3 chromatin binding in a cell cycle-dependent manner, further integrating post-translational regulation. Overexpression of wild-type MCM3 can cause G1 arrest and S phase delay, while specific mutants such as T722A can rescue these effects. Although MCM3 is essential for replication fork progression and genome stability, only a fraction of loaded complexes are actively engaged in replication, with excess complexes serving as backup origins and participating in checkpoint signaling. MCM3 also interacts with other replication and chromatin-associated proteins, regulating origin specificity and coordinating replication with cell cycle progression. Mutations or imbalances in MCM3 expression can lead to defects in replication licensing, genomic instability, and cell cycle arrest.

Background

MCM3 is a core subunit of the minichromosome maintenance (MCM) 2–7 complex, which acts as the essential replicative helicase for the initiation and elongation of DNA replication in eukaryotic cells. This large protein, about 971 amino acids, shares significant homology with MCM2, especially in three conserved regions critical for helicase activity and DNA binding. Structurally, MCM3 contains multiple phosphorylation sites and interfaces that mediate interactions with other MCM subunits, particularly MCM5, and is incorporated into the hexameric MCM2-7 ring that loads onto replication origins as part of the pre-replicative complex (pre-RC) during late M and G1 phases. Recruitment of MCM3 to origins depends on the origin recognition complex (ORC), CDC6, and CDT1, ensuring that replication licensing occurs only once per cell cycle. MCM3’s activity is tightly regulated by phosphorylation, notably by cyclin-dependent kinases such as cyclin E/Cdk2, which phosphorylates threonine 722 to promote chromatin loading but can inhibit replication if dysregulated. It is also a substrate for checkpoint kinases ATM and ATR, linking MCM3 to DNA damage responses and replication checkpoint pathways. Acetylation by MCM3AP inhibits DNA replication initiation and cell cycle progression, adding another layer of control. The prolyl isomerase Pin1 modulates MCM3 chromatin binding in a cell cycle-dependent manner, further integrating post-translational regulation. Overexpression of wild-type MCM3 can cause G1 arrest and S phase delay, while specific mutants such as T722A can rescue these effects. Although MCM3 is essential for replication fork progression and genome stability, only a fraction of loaded complexes are actively engaged in replication, with excess complexes serving as backup origins and participating in checkpoint signaling. MCM3 also interacts with other replication and chromatin-associated proteins, regulating origin specificity and coordinating replication with cell cycle progression. Mutations or imbalances in MCM3 expression can lead to defects in replication licensing, genomic instability, and cell cycle arrest.

References
https://pubmed.ncbi.nlm.nih.gov/21965652/ https://pubmed.ncbi.nlm.nih.gov/2044961/

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%