A carboxy-terminal region of the hepatitis B virus X protein promotes DNA interaction of CREB and mimics the native protein for transactivation function. Virus Genes 2003 May;26(3):227-38
Date
07/24/2003Pubmed ID
12876451DOI
10.1023/a:1024491028647Scopus ID
2-s2.0-0042315410 (requires institutional sign-in at Scopus site) 15 CitationsAbstract
Earlier we had shown that the conserved region E (residues 120-140) of HBV X protein (HBx) is crucial for transactivation. To investigate this region further, its oligomerisation was considered necessary to augment intracellular biochemical stability. Two to ten unit long tandem repeats of the E region (X16-n) were generated and their expression vectors constructed. Transient transfection of the E expression vectors along with different CAT constructs showed increase in the reporter activity. Interestingly a direct correlation was observed between the number of E repeat units in an expression vector and the level of transactivation. The transactivation levels with decameric X16 on different reporter constructs were comparable to those of the wild type HBx. Co-expression of X16 in a stable CHO-K1 cell line expressing the native HBx, showed co-operativity for transactivation. Further, X16 facilitated the binding of cAMP response element binding protein (CREB) to its responsive element just like the native HBx. The present study suggests that the C-terminal 'E' region of HBx represents its transactivation domain that acts by promoting the interaction of transcription factors to their cognate response elements.
Author List
Reddi H, Kumar R, Jain SK, Kumar VMESH terms used to index this publication - Major topics in bold
AnimalsCHO Cells
Cricetinae
Cyclic AMP Response Element-Binding Protein
DNA, Viral
Gene Expression Regulation, Viral
Hepatitis B virus
Promoter Regions, Genetic
Tandem Repeat Sequences
Trans-Activators
Transcriptional Activation
Transfection
Viral Regulatory and Accessory Proteins