Heterochromatin protein 1 (HP1) is a family of heterochromatic adaptor molecules involved in both gene silencing and higher order chromatin structure (1).
All three HP1 family members (alpha, beta and gamma) are primarily associated with centromeric heterochromatin; however, HP1beta and gamma also localize to euchromatic sites in the genome (2,3).
HP1 proteins are approximately 25kD in size and each contains a conserved amino-terminal chromodomain, followed by a variable hinge region and a conserved carboxy-terminal chromoshadow domain.
The chromodomain facilitates binding to histone H3 tri-methylated on Lys9, a histone "mark" closely associated with centromeric heterochromatin (4,5).
The variable hinge region binds both RNA and DNA in a sequence-independent manner (6).
The chromoshadow domain mediates the dimerization of HP1 proteins, in addition to binding multiple proteins implicated in gene silencing and heterochromatin formation, including the SUV39H histone methyltransferase, the DNMT1 and DNMT3a DNA methyltransferases and the p150 subunit of chromatin-assembly factor-1 (CAF1) (7-9).
In addition to contributing to heterochromatin formation and propagation, HP1 and SUV39H are also found complexed with retinoblastoma (Rb) and E2F6 proteins, both of which function to repress euchromatic gene transcription in quiescent cells (10,11).
HP1 proteins are subject to multiple types of post-translational modifications, including phosphorylation, acetylation, methylation, ubiquitination and sumoylation, suggesting multiple means of regulation (12-14).
HP1gamma is phosphorylated on Ser83 by protein kinase A (PKA) in vitro, and activation of PKA by forskolin and IBMX treatment leads to increased phosphorylation in vivo (14).
Phosphorylation of HP1gamma on Ser83 also increases in mitosis as demonstrated by our Phospho-HP1gamma (Ser83) Antibody, which shows increased immunofluorescent staining in untreated mitotic cells and increased Western blot signal in lysates from cells arrested in mitosis by treatment with paclitaxel.
Phosphorylation of Ser83 only occurs on a subpopulation of HP1gamma found associated with euchromatin, specifically HP1gamma bound to coding regions of active genes (14).
This phosphorylation impairs the ability of HP1gamma to silence transcription and may be a marker for transcription elongation (14).
Applications:Suitable for use in Immunofluorescence, Western Blot and Immunoprecipitation.
Other applications not tested.
Recommended Dilution:Immunofluorescence: 1:200Western Blot: 1:1000, incubate membrane with diluted antibody in 5% BSA, 1X TBS, 0.1% Tween-20 at 4°C with gentle shaking, overnight
Immunoprecipitation: 1:25Optimal dilutions to be determined by the researcher.
Storage and Stability:May be stored at 4°C for short-term only.
Aliquot to avoid repeated freezing and thawing.
Store at -20°C.
Aliquots are stable for 12 months.
For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
仕様
Size：100ul
Host：rabbit
Source Antibody：human
Grade：Affinity Purified
Purity：Purified by affinity chromatography.
Form：Supplied as a liquid in 10mM HEPES, pH 7.5, 150mM sodium chloride, 0.1mg/ml BSA, 50% glycerol.
Specificity：Recognizes endogenous levels of human HP1gamma protein only when phosphorylated on Ser83 (also referred to as Ser93 of the unprocessed form of HP1gamma). Does not cross-react with HP1alpha or HP1beta proteins. Species Crossreactivity: mouse, monkey and rat
Isotype：IgG
Calc Applications Abbrev：IF IP WB
Calc Crossreactivity：Hu Mk Mo Rt
Immunogen：Synthetic phosphopeptide corresponding to amino acids surrounding Ser83 of human HP1gamma. Species sequence homology: D. melanogaster, bovine and equine (100%)
