Increased association between Epstein-Barr virus EBNA2 from type 2 strains and the transcriptional repressor BS69 restricts EBNA2 activity

Autor: Rajesh, Ponnusamy, Ritika, Khatri, Paulo B, Correia, C David, Wood, Erika J, Mancini, Paul J, Farrell, Michelle J, West
Rok vydání: 2018
Předmět:
Models
Molecular
Herpesvirus 4
Human
B Cells
Genes
Viral
Cell Cycle Proteins
Artificial Gene Amplification and Extension
Biochemistry
Polymerase Chain Reaction
Small-Angle Scattering
Scattering
Database and Informatics Methods
White Blood Cells
Binding Analysis
Animal Cells
hemic and lymphatic diseases
Medicine and Health Sciences
Materials
Pathology and laboratory medicine
B-Lymphocytes
Physics
Medical microbiology
DNA-Binding Proteins
Chemistry
Physical Sciences
Viruses
Cellular Types
Pathogens
Co-Repressor Proteins
Sequence Analysis
Research Article
Herpesviruses
Bioinformatics
Immune Cells
Immunology
Materials Science
Research and Analysis Methods
Microbiology
Cell Line
Viral Proteins
Sequence Motif Analysis
Humans
Epstein-Barr virus
Protein Interaction Domains and Motifs
Amino Acid Sequence
Protein Structure
Quaternary
Antibody-Producing Cells
Dimers
Molecular Biology Techniques
Molecular Biology
Chemical Characterization
Binding Sites
Blood Cells
Host Microbial Interactions
Organisms
Viral pathogens
Biology and Life Sciences
Polypeptides
Cell Biology
Cell Transformation
Viral
Polymer Chemistry
Microbial pathogens
Amino Acid Substitution
Epstein-Barr Virus Nuclear Antigens
Oligomers
Mutation
Trans-Activators
Carrier Proteins
Peptides
DNA viruses
Zdroj: PLoS Pathogens
ISSN: 1553-7374
Popis: Natural variation separates Epstein-Barr virus (EBV) into type 1 and type 2 strains. Type 2 EBV is less transforming in vitro due to sequence differences in the EBV transcription factor EBNA2. This correlates with reduced activation of the EBV oncogene LMP1 and some cell genes. Transcriptional activation by type 1 EBNA2 can be suppressed through the binding of two PXLXP motifs in its transactivation domain (TAD) to the dimeric coiled-coil MYND domain (CC-MYND) of the BS69 repressor protein (ZMYND11). We identified a third conserved PXLXP motif in type 2 EBNA2. We found that type 2 EBNA2 peptides containing this motif bound BS69CC-MYND efficiently and that the type 2 EBNA2TAD bound an additional BS69CC-MYND molecule. Full-length type 2 EBNA2 also bound BS69 more efficiently in pull-down assays. Molecular weight analysis and low-resolution structures obtained using small-angle X-ray scattering showed that three BS69CC-MYND dimers bound two molecules of type 2 EBNA2TAD, in line with the dimeric state of full-length EBNA2 in vivo. Importantly, mutation of the third BS69 binding motif in type 2 EBNA2 improved B-cell growth maintenance and the transcriptional activation of the LMP1 and CXCR7 genes. Our data indicate that increased association with BS69 restricts the function of type 2 EBNA2 as a transcriptional activator and driver of B cell growth and may contribute to reduced B-cell transformation by type 2 EBV.
Author summary Epstein-Barr virus (EBV) drives the development of many human cancers worldwide including specific types of lymphoma and carcinoma. EBV infects B lymphocytes and immortalises them, thus contributing to lymphoma development. The virus promotes B lymphocyte growth and survival by altering the level at which hundreds of genes are expressed. The EBV protein EBNA2 is known to activate many growth-promoting genes. Natural variation in the sequence of EBNA2 defines the two main EBV strains: type 1 and type 2. Type 2 strains immortalise B lymphocytes less efficiency and activate some growth genes poorly, although the mechanism of this difference is unclear. We now show that sequence variation in type 2 EBNA2 creates a third site of interaction for the repressor protein (BS69, ZMYND11). We have characterised the complex formed between type 2 EBNA2 and BS69 and show that three dimers of BS69 form a bridged complex with two molecules of type 2 EBNA2. We demonstrate that mutation of the additional BS69 interaction site in type 2 EBNA2 improves its growth-promoting and gene induction function. Our results therefore highlight a molecular mechanism that may contribute to the different B lymphocyte growth promoting activities of EBV strains. This aids our understanding of immortalisation by EBV.
Databáze: OpenAIRE
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