HBV X protein (HBX) interacts with general transcription factor TFIIB both in vitro and in vivo.
OBJECTIVE
In order to demonstrate the binding of HBV X protein (HBX) with the general transcription factor TFIIB.


METHODS
In vitro glutathion S-transferase (GST) resin Pull-Down assay and Far-Western Blotting assay, in vivo Co-immunoprecipition assay were used.


RESULTS
The X199 (51-99) domain of HBX is reponsible for HBX binding to TFIIB. While the d10 domain (125-295) of TFIIB is required for TFIIB binding to HBX. When the two basic amino acids (K) at position 178 and 189 of TFIIB were substituted by neutral amino acids (L), the binding of TFIIB K178L and K189L to HBX was siginificantly reduced. When the the basic amino acids were substituted by the acidic amino acids (E), the binding of TFIIB K178E and K189E to HBX were almost lost. In vitro results of HBX binding to TFIIB were further confirmed by in vivo co-immunoprecipitation assay. Our results also indicated that the Woodchuck hepatitis virus X protein (WHX) interacts with TFIIB.


CONCLUSIONS
These results suggested that the communication between HBX and general transcription factor TFIIB is one of the mechanisms which account for its transcriptional transactivation.
Yang
Y
Y
Department of Infectious Diseases, The First Affiliated Hospital of Zhejiang Medical University, Hangzhou 310003.
Ma
Y
Y
Zhen
L
L
Chen
Y
Y
Ma
W
W
Murakami
S
S
D001665:Binding Sites; D006515:Hepatitis B virus / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology; D011485:Protein Binding; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D035581:Transcription Factor TFIIB / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured; D014764:Viral Proteins / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins
D015534:Trans-Activators; D035581:Transcription Factor TFIIB; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; C090237:protein X, Woodchuck hepatitis B virus