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The adenovirus-2 E1B-55K protein interacts with a mSin3A/histone deacetylase 1 complex
1Department of Medical Biochemistry and Microbiology, Uppsala University, BMC, Box 582, 751 23, Uppsala, Sweden.
Abstract:
The adenovirus E1B-55K protein is a multifunctional phosphoprotein that regulates nuclear to cytoplasmic export of host cell and viral mRNAs during lytic viral growth. E1B-55K also blocks apoptosis by binding and functionally inactivating the human tumor suppressor protein p53. Here, we show that E1B-55K interacts with histone deacetylase 1 (HDAC1) and the transcriptional corepressor protein mSin3A, both in the adenovirus-transformed 293 cell line and during a lytic adenovirus infection. Furthermore, we show that the central amino acids 156-261 in E1B-55K are necessary for efficient HDAC1 interaction. Importantly, the E1B-55K/mSin3A/HDAC1 complex is also enzymatically active, catalyzing deacetylation of a histone substrate peptide. Collectively, our results suggest that E1B-55K interaction with mSin3A/HDAC1 containing complexes may be significant for one or several of the multiple activities ascribed to this protein.
Insights
Adenovirus E1B-55K protein binds histone deacetylase 1 (HDAC1) and mSin3A. This interaction, involving specific amino acids in E1B-55K, forms an active complex suggesting a role in viral activities.
Area of Science:
- Molecular Biology
- Virology
- Biochemistry
Background:
- Adenovirus E1B-55K protein is crucial for viral replication and host cell manipulation.
- E1B-55K regulates mRNA export and inhibits apoptosis by interacting with p53.
- The precise molecular mechanisms underlying E1B-55K's diverse functions are not fully understood.
Purpose of the Study:
- To investigate the interaction of adenovirus E1B-55K protein with cellular proteins involved in transcriptional regulation.
- To identify the specific regions of E1B-55K critical for these interactions.
- To determine the functional significance of the E1B-55K complex with its interacting partners.
Main Methods:
- Co-immunoprecipitation assays to detect protein-protein interactions.
- Analysis of adenovirus-transformed cell lines and cells undergoing lytic infection.
- Site-directed mutagenesis to map interaction domains within E1B-55K.
- In vitro enzymatic assays to assess the activity of the formed protein complex.
Main Results:
- Adenovirus E1B-55K protein was found to interact with histone deacetylase 1 (HDAC1) and mSin3A.
- The central amino acid region (156-261) of E1B-55K is essential for efficient binding to HDAC1.
- The E1B-55K/mSin3A/HDAC1 complex demonstrated enzymatic activity, specifically histone deacetylation.
Conclusions:
- Adenovirus E1B-55K protein interacts with the mSin3A/HDAC1 transcriptional corepressor complex.
- This interaction is mediated by a specific region within E1B-55K and results in an enzymatically active complex.
- The findings suggest a significant role for the E1B-55K interaction with mSin3A/HDAC1 in mediating adenovirus functions.