Product Pathways - Cell Cycle / Checkpoint
SignalSilence® p21 Waf1/Cip1 siRNA II #6558
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.
Western blot analysis of extracts from HeLa cells, transfected with 100 nM SignalSilence® Control siRNA (Fluorescein Conjugate) #6201 (-) or SignalSilence® p21 Waf1/Cip1 siRNA II (+), using p21 Waf1/Cip1 (12D1) Rabbit mAb #2947 and α-Tubulin (11H10) Rabbit mAb #2125. The p21 Waf1/Cip1 (12D1) Rabbit mAb confirms silencing of p21 Waf1/Cip1 expression and α-Tubulin (11H10) Rabbit mAb is used to control for loading and specificity of p21 Waf1/Cip1 siRNA.
SignalSilence® p21 Waf1/Cip1 siRNA II from Cell Signaling Technology (CST) allows the researcher to specifically inhibit p21 Waf1/Cip1 expression using RNA interference, a method whereby gene expression can be selectively silenced through the delivery of double stranded RNA molecules into the cell. All SignalSilence® siRNA products are rigorously tested in-house and have been shown to reduce target protein expression by western analysis.
Directions for Use
CST recommends transfection with 100 nM p21 Waf1/Cip1 siRNA II 48 to 72 hours prior to cell lysis. For transfection procedure, follow protocol provided by the transfection reagent manufacturer. Please feel free to contact CST with any questions on use.
Each vial contains the equivalent of 100 transfections, which corresponds to a final siRNA concentration of 100 nM per transfection in a 24-well plate with a total volume of 300 μl per well.
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).
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- Cheng, J. et al. (1999) EMBO J. 18, 1571-1583.
- Flores-Rozas, H. et al. (1994) Proc. Natl. Acad. Sci. USA 91, 8655-8659.
- Wang, Y. and Prives, C. (1995) Nature 376, 88-91.
- Sheaff, R.J. et al. (2000) Cell 5, 403-410.
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- 6201 SignalSilence® Control siRNA (Fluorescein Conjugate)
- 6568 SignalSilence® Control siRNA (Unconjugated)
- 6456 SignalSilence® p21 Waf1/Cip1 siRNA I
- 2947 p21 Waf1/Cip1 (12D1) Rabbit mAb
Limited Use Label License, RNA interference: This product is licensed under European Patent 1144623 and foreign equivalents from Ribopharma AG, Kulmbach, Germany and is provided only for use in non-commercial research specifically excluding use (a) in drug discovery or drug development, including target identification or target validation, by or on behalf of a commercial entity, (b) for contract research or commercial screening services, (c) for the production or manufacture of siRNA-related products for sale, or (d) for the generation of commercial databases for sale to Third Parties. Information about licenses for these and other commercial uses is available from Ribopharma AG, Fritz-Hornschuch-Str. 9, D-95326 Kulmbach, Germany.
For Research Use Only. Not For Use In Diagnostic Procedures.