Flow cytometric analysis of Jurkat cells, untreated (blue) or treated with JQ1 (500nM, 72 hours; green), using HEXIM1 (D5Y5K) Rabbit mAb (PE Conjugate).
Flow cytometric analysis of HeLa cells using HEXIM1 (D5Y5K) Rabbit mAb (PE Conjugate) (blue) compared to concentration-matched Rabbit (DA1E) mAb IgG XP® Isotype Control (PE Conjugate) #5742 (red).
This Cell Signaling Technology antibody is conjugated to phycoerythrin (PE) and tested in-house for direct flow cytometry analysis in human cells. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated HEXIM1 (D5Y5K) Rabbit mAb #12604.
Supplied in PBS (pH 7.2), less than 0.1% sodium azide and 2 mg/ml BSA. Store at 4°C. Do not aliquot the antibody. Protect from light. Do not freeze.
All reagents required for this protocol may be efficiently purchased together in our Intracellular Flow Cytometry Kit (Methanol) #13593, or individually using the catalog numbers listed below.
NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.
NOTE: When including fluorescent cellular dyes in your experiment (including viability dyes, DNA dyes, etc.), please refer to the dye product page for the recommended protocol. Visit www.cellsignal.com for a full listing of cellular dyes validated for use in flow cytometry.
NOTE: Adherent cells or tissue should be dissociated and in single-cell suspension prior to fixation.
NOTE: Optimal centrifugation conditions will vary depending upon cell type and reagent volume. Generally, 150-300g for 1-5 minutes will be sufficient to pellet the cells.
NOTE: If using whole blood, lyse red blood cells and wash by centrifugation prior to fixation.
NOTE: Antibodies targeting CD markers or other extracellular proteins may be added prior to fixation if the epitope is disrupted by formaldehyde and/or methanol. The antibodies will remain bound to the target of interest during the fixation and permeabilization process. However, note that some fluorophores (including PE and APC) are damaged by methanol and thus should not be added prior to permeabilization. Conduct a small-scale experiment if you are unsure.
NOTE: Count cells using a hemocytometer or alternative method.
posted July 2009
revised June 2020
Protocol Id: 407
HEXIM1 (D5Y5K) Rabbit mAb (PE Conjugate) recognizes endogenous levels of total HEXIM1 protein.
Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Gly63 of human HEXIM1 protein.
Hexamethylene bis-acetamide-inducible protein 1 (HEXIM1) was originally identified in vascular smooth muscle cells as a protein that is upregulated upon treatment with the differentiating agent hexamethylene bisacetamide (1). HEXIM1 binds 7SK RNA, a highly abundant non-coding RNA, and together they act as a potent inhibitor of positive transcription elongation factor b (P-TEFb) (2,3). P-TEFb phosphorylates the C-terminal domain of the largest subunit of RNA polymerase II and is an important regulator of transcription elongation (4-8). 7SK RNA-bound HEXIM1 interacts with the cyclin T1 subunit of P-TEFb, sequestering P-TEFb in an inactive form leading to transcription inhibition (2,3). The regulation of the relative ratio of inactive to active P-TEFb in the cell by HEXIM1/7SK RNA is thought to play a critical role in regulation of a wide range of cellular gene expression programs such as estrogen and glucocorticoid receptor regulated genes (9-12).
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