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p21 Waf1/Cip1 (12D1) Rabbit mAb (PE Conjugate) #8865
Gallery: p21 Waf1/Cip1 (12D1) Rabbit mAb (PE Conjugate) #8865
Flow Cytometry, Methanol Permeabilization Protocol for Direct Conjugates
A. Solutions and Reagents
NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.
- 20X Phosphate Buffered Saline (PBS): (#9808) To prepare 1 L 1X PBS: add 50 ml 20X PBS to 950 ml dH2O, mix.
- 16% Formaldehyde (methanol free).
- 100% methanol.
- Incubation Buffer: Dissolve 0.5 g Bovine Serum Albumin (BSA) (#9998) in 100 ml 1X PBS. Store at 4°C.
NOTE: If using whole blood, lyse red blood cells and wash by centrifugation prior to fixation.
- Collect cells by centrifugation and aspirate supernatant.
- Resuspend cells in 0.5-1 ml 1X PBS. Add formaldehyde to obtain a final concentration of 4%.
- Fix for 15 min at room temperature.
- Wash by centrifugation with excess 1X PBS. Discard supernatant in appropriate waste container. Resuspend cells in 0.5-1 ml 1X PBS.
- Permeabilize cells by adding ice-cold 100% methanol slowly to pre-chilled cells, while gently vortexing, to a final concentration of 90% methanol.
- Incubate 30 min on ice.
- Proceed with immunostaining (Section D) or store cells at -20°C in 90% methanol.
- Aliquot desired number of cells into tubes or wells.
- Wash cells by centrifugation in excess 1X PBS to remove methanol. Discard supernatant in appropriate waste container. Repeat if necessary.
- Resuspend cells in 100 µl of diluted antibody conjugate (prepared in incubation buffer at the recommended dilution).
- Incubate for 1 hr at room temperature. Protect from light.
- Wash by centrifugation in incubation buffer. Discard supernatant. Repeat.
- Resuspend cells in 1X PBS and analyze on flow cytometer; alternatively, for DNA staining, proceed to optional DNA stain (Section E).
E. Optional DNA Dye
- Resuspend cells in 0.5 ml of DNA dye (e.g. Propidium Iodide (PI)/RNase Staining Solution #4087).
- Incubate for at least 5 min at room temperature.
- Analyze cells in DNA staining solution on flow cytometer.
posted July 2009
revised June 2017
p21 Waf1/Cip1 (12D1) Rabbit mAb (PE Conjugate) detects endogenous levels of total p21 protein. The antibody does not cross-react with other CDK inhibitors.Species Reactivity: Human, Monkey Species predicted to react based on 100% sequence homology: Dog
Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues near the carboxy terminus of human p21 protein.
This Cell Signaling Technology antibody is conjugated to phycoerythrin (PE) and tested in-house for direct flow cytometry analysis in human cells. The antibody is expected to exhibit the same species cross-reactivity as the unconjugated p21 Waf1/Cip1 (12D1) Rabbit mAb #2947.
The tumor suppressor protein p21 Waf1/Cip1 acts as an inhibitor of cell cycle progression. It functions in stoichiometric relationships forming heterotrimeric complexes with cyclins and cyclin-dependent kinases. In association with CDK2 complexes, it serves to inhibit kinase activity and block progression through G1/S (1). However, p21 may also enhance assembly and activity in complexes of CDK4 or CDK6 and cyclin D (2). The carboxy-terminal region of p21 is sufficient to bind and inhibit PCNA, a subunit of DNA polymerase, and may coordinate DNA replication with cell cycle progression (3). Upon UV damage or during cell cycle stages when cdc2/cyclin B or CDK2/cyclin A are active, p53 is phosphorylated and upregulates p21 transcription via a p53-responsive element (4). Protein levels of p21 are downregulated through ubiquitination and proteasomal degradation (5).
For Research Use Only. Not For Use In Diagnostic Procedures. Cell Signaling Technology is a trademark of Cell Signaling Technology, Inc.