Chromobox Homolog 4 (CBX4) antibody

Antigen: Chromobox Homolog 4 (CBX4)

Synonyms: PC2, hPC2, NBP16, MPc2, MGC143697, MGC143698, MGC198077, MGC198079, im:6911625, zgc:158588, CBX4

Clonality: Polyclonal

Host: Rabbit

Reactivity: Human, Cow (Bovine), Mouse (Murine), Rat (Rattus)

Application: ELISA, Western Blotting (WB), Immunoprecipitation (IP)

Catalog no.: ABIN129594

Additional Information

Alternative name: PC2

Immunogen: This affinity purified antibody was prepared from whole rabbit serum produced by repeated immunizations with a synthetic peptide corresponding to aa 95-107 of Human PC2 protein.

Format: Liquid (sterile filtered)

Description: PC2 is the human homolog of the Drosophila 'Polycomb' (Pc) protein which has been identified as a gene family member associated with a cellular memory system that is responsible for the inheritance of gene activity by progeny cells. The human Pc homolog gene is more closely related to a Xenopus Pc homolog, XPc, than to a previously described human Pc homolog, CBX2 (hPc1). However, the hPc2 and CBX2/hPc1 proteins are shown to colocalize in interphase nuclei of human U-2 OS osteosarcoma cells, suggesting that the proteins are part of a common protein complex. The human protein is believed to function as a repressor of proto-oncogene activity and that interference with hPc2 function can lead to derepression of proto-oncogene transcription and subsequently to cellular transformation. Other reports describe PC2 as a protein that has SUMO E3 activity for the corepressors CtBP and CtBP2.

Specificity: This is an affinity purified antibody produced by immunoaffinity chromatography using the immunizing peptide after immobilization to a solid phase. Reactivity occurs against human PC2 protein. Cross reactivity with PC2 protein from mouse may occur as a 92% homology (BLAST) is noted for the immunized sequence. Cross reactivity with PC2 protein from other sources is not known.

Application Details

Application Notes: This affinity purified antibody has been tested for use in immunofluorescence staining of cultured cells and western blotting using transfected cell lysates. The antibody is also functional by ELISA. Reactivity in other immunoassays is unknown. Dilutions for western blotting represent a starting point dilution and further optimization may be required. The antibody detects a band of approximately 82 kDa (predicted molecular weight: 61.4 kDa). In immunofluoresence, this antibody detects the expected discrete nuclear structure that is termed the PcG body, corresponding to the known localization of PC2. The antibody has been successfully used to detect FLAG-tagged transfected hPC2 (see figure below). It detects a weak band that probably corresponds to endogenous PC2, however, a strong secondary band is also seen at 50kD in all cell lines thus far tested. This suggests that the antibody may also react with another highly expressed ubiquitous protein. Dilutions: ELISA 1:10,000 - 1:40,000 WESTERN BLOT 1:1,000 - 1:4,000 IF MICROSCOPY 1:100 - 1:400 OTHER APPLICATIONS User Optimized

Concentration: 1.36 mg/ml (by UV absorbance at 280 nm)

Buffer: Stabilizer: None. Preservative: 0.01% (w/v) Sodium Azide. Buffer: 0.02 M Potassium Phosphate, 0.15 M Sodium Chloride, pH 7.2.

Storage: Store vial at -20° C prior to opening. Dilute only prior to immediate use. For extended storage aliquot contents and freeze at -20° C or below. Avoid cycles of freezing and thawing. Expiration date is one (1) year from date of opening.

Research Area: Chromatin and Nuclear Signaling, Chromatin Binding Proteins

Restrictions: For Research Use only

Images

Immunofluorescence Microscopy. antibodies-online's anti-hPC2 antibody was used for immunofluorescent imaging of human cells (U2OS). The image reveals the expected discrete nuclear structure that is termed the PcG body corresponding to the known localization of PC2 (see Satijn et al. below). IF was performed after fixation in PBS with 4% PF for 5 min, permeabilization with 0.5% Triton X100-PBS for 5 min, and blocking with 5% milk / 0.2% Tween for 1 h. Primary antibody used at 1:200 in 5% milk / 0.2% Tween for 1 h, secondary antibody for 30 min. All blocking and incubation steps carried out at 37

Western blotting. Analysis shows the detection of human PC2 in probed lysates using antibodies-online's Affinity Purified anti-hPC2 antibody. The panel on the left shows the blot probed with anti-hPC2. The panel on the right is the same blot reprobed with anti-FLAG antibody to confirm the presence of FLAG tagged recombinant PC2 in the lysate. In the left panel the band labeled as hPC2 is FLAG-tagged transfected hPC2 in 293T cells. The bands labeled with stars are likely endogenous hPC2. In the right panel the band labeled hPC2 is FLAG-tagged transfected hPC2 in 293T cells. Data contributed by Dr Ari Melnick, Albert Einstein College of Medicine.