Hepatitis B Protein X (HBx) (E. coli)

Description

Total 154 AA. MW: 17 kDa (calculated). 153 AA of recombinant HBx protein and one extra AA, N-terminal methionin (highlighted).

Amino Acid Sequence

Source

E. coli

Purity

>95%

SDS-PAGE gel

12% SDS-PAGE separation of HBx 1. M.W. marker – 14, 21, 31, 45, 66, 97 kDa 2. reduced and heated sample, 5μg/lane 3. non-reduced and non-heated sample, 5μg/lane

Formulation

Filtered (0,4 μm) and lyophilized in 0.5 mg/mL in 0.05 M Acetate buffer pH4

Reconstitution

Add 0.1M Acetate buffer pH4 to prepare a working stock solution of approximately 0.5 mg/mL and let the lyophilized pellet dissolve completely. For conversion into higher pH value, we recommend intensive dilution by relevant buffer to a concentration of 10μg/mL. In higher concentrations the solubility of this antigen is limited. Product is not sterile! Please filter the product by an appropriate sterile filter before using it in the cell culture.

Storage, Stability/Shelf Life

Store lyophilized protein at –20°C. Lyophilized protein remains stable until the expiry date when stored at –20°C. Aliquot reconstituted protein to avoid repeated freezing/thawing cycles and store at –80°C for long term storage. Reconstituted protein can be stored at 4°C for a limited period of time; it does not show any change after two weeks at 4°C.

Quality Control Test

BCA to determine quantity of the protein.

SDS PAGE to determine purity of the protein.

Applications

ELISA, Western blotting

Note

This product is intended for research use only.

Introduction to the Molecule

Hepatitis B virus X protein (HBx) is a 17 kD transcriptional coactivator that plays a significant role in the regulation of genes involved in inflammation and cell survival. It regulates many transcription factors including nuclear factor kappa B (NF-kappaB) and plays a key role in hepatocarcino­genesis. HBx facilitates the binding of cAMP response element binding protein (CREB) to its responsive element. HBx stabilizes the cellular coactivator ASC-2 through direct protein-protein interaction, affecting the regulation of genes actively transcribed in liver cancer cells.

HBx transactivates both JNK and MAPK signal transduction pathways in association with the mobilization of cytosolic Ca²⁺. The communication between HBx and general transcription factor TFIIB is also one of the mechanisms which account for its transcriptional transactivation.

HBx decreased the expression of PTEN a known tumor suppressor and a negative regulator of phosphatidyli­nositol 3'-kinase/AKT and HBx decreased the expression of PTEN in HBx-transfected cells.

The etiology of hepatocellular carcinoma (HCC) is involved with hepatitis B virus (HBV) infection and HBx in particular plays a role in the development of HBV-related HCC. The persistence of HBx is important to the pathogenesis of early HCC and HBx expression in the liver during chronic HBV infection may be an important prognostic marker for the development of HCC.

References

• Song CZ, Bai ZL, Song CC, Wang QW. Aggregate formation of hepatitis B virus X protein affects cell cycle and apoptosis. World J Gastroenterol. 2003 Jul; 9(7): 1521-4.
• Hwang GY, Lin CY, Huang LM, Wang YH, Wang JC, Hsu CT, Yang SS, Wu CC. Detection of the hepatitis B virus X protein (HBx) antigen and anti-HBx antibodies in cases of human hepatocellular carcinoma. J Clin Microbiol. 2003 Dec; 41(12): 5598-603.
• Arbuthnot P, Kew M. Hepatitis B virus and hepatocellular carcinoma. Int J Exp Pathol. 2001 Apr; 82(2): 77-100. Review.
• Tralhao JG, Roudier J, Morosan S, Giannini C, Tu H, Goulenok C, Carnot F, Zavala F, Joulin V, Kremsdorf D, Brechot C. Paracrine in vivo inhibitory effects of hepatitis B virus X protein (HBx) on liver cell proliferation: an alternative mechanism of HBx-related pathogenesis. Proc Natl Acad Sci U S A. 2002 May 14; 99(10): 6991-6.
• Madden CR, Slagle BL. Stimulation of cellular proliferation by hepatitis B virus X protein. Dis Markers. 2001; 17(3): 153-7. Review.