Title

Mutational analysis of the latency-associated nuclear antigen DNA-binding domain of Kaposi's sarcoma-associated herpesvirus reveals structural conservation among gammaherpesvirus origin-binding proteins

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology; Program in Bioinformatics and Integrative Biology

Date

9-2010

Document Type

Article

Medical Subject Headings

Amino Acid Sequence; Amino Acid Substitution; Animals; Antigens, Viral; Binding Sites; Cell Line; Cercopithecus aethiops; Conserved Sequence; DNA Replication; DNA, Viral; Electrophoretic Mobility Shift Assay; Epstein-Barr Virus Nuclear Antigens; Evolution, Molecular; Gammaherpesvirinae; Herpesvirus 8, Human; Humans; Models, Molecular; Molecular Sequence Data; Mutant Proteins; Mutation; Nuclear Proteins; Protein Multimerization; Protein Structure, Quaternary; Protein Structure, Tertiary; Sequence Homology, Amino Acid; Structural Homology, Protein

Disciplines

Bioinformatics | Computational Biology | Systems Biology | Virology

Abstract

The latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus functions as an origin-binding protein (OBP) and transcriptional regulator. LANA binds the terminal repeats via the C-terminal DNA-binding domain (DBD) to support latent DNA replication. To date, the structure of LANA has not been solved. Sequence alignments among OBPs of gammaherpesviruses have revealed that the C terminus of LANA is structurally related to EBNA1, the OBP of Epstein-Barr virus. Based on secondary structure predictions for LANA(DBD) and published structures of EBNA1(DBD), this study used bioinformatics tools to model a putative structure for LANA(DBD) bound to DNA. To validate the predicted model, 38 mutants targeting the most conserved motifs, namely three alpha-helices and a conserved proline loop, were constructed and functionally tested. In agreement with data for EBNA1, residues in helices 1 and 2 mainly contributed to sequence-specific DNA binding and replication activity, whilst mutations in helix 3 affected replication activity and multimer formation. Additionally, several mutants were isolated with discordant phenotypes, which may aid further studies into LANA function. In summary, these data suggest that the secondary and tertiary structures of LANA and EBNA1 DBDs are conserved and are critical for (i) sequence-specific DNA binding, (ii) multimer formation, (iii) LANA-dependent transcriptional repression, and (iv) DNA replication.

Rights and Permissions

Citation: J Gen Virol. 2010 Sep;91(Pt 9):2203-15. doi: 10.1099/vir.0.020958-0. Link to article on publisher's site

Related Resources

Link to Article in PubMed