Work

Quantitative Analysis of the Bidirectional Viral G-Protein-Coupled Receptor and Lytic Latency-Associated Nuclear Antigen Promoter of Kaposi's Sarcoma-Associated Herpesvirus

Year: 2012

Type: article

Abstract: Kaposi's sarcoma-associated herpesvirus (KSHV) establishes sustained latent persistence in susceptible cells. This is dependent on the latency-associated nuclear antigen (LANA). Understanding how LANA transcription is regulated thus aids our fundamental understanding of KSHV biology. Two hundred ninety-four base pairs are sufficient to regulate LANA transcription in response to the viral RTA protein and RBPjκ. The same region controls K14/viral G-protein-coupled receptor (vGPCR) transcription in the opposite direction. We used a quantitative analysis in conjunction with specific nucleotide substitutions and defined gain-of-function and loss-of-function RTA mutants to dissect this region. We used a bidirectional reporter driving red and green luciferase to study the LANApi and K14p promoters simultaneously. This established that LANApi/K14p functions as a canonical bidirectional promoter. Both were TATA dependent. K14p was favored by ∼50-fold in this context. Eliminating the distal LANApi TATA box increased maximal output and lowered the induction threshold (T) of K14p even further. Two RBPjκ binding sites were independently required; however, at high concentrations of RTA, direct interactions with an RTA-responsive element (RRE) could complement the loss of one RBPjκ binding site. Intracellular Notch (ICN) was no longer able to activate RBPjκ in the viral context. This suggests a model whereby KSHV alters ICN-RBPjκ gene regulation. When the architecture of this pair of head-to-head RBPjκ binding sites is changed, the sites now respond exclusively to the viral transactivator RTA and no longer to the host mediator ICN.

Source: Journal of Virology

DOI: 10.1128/jvi.00881-12

Authors: Isaac B. Hilton, Dirk P. Dittmer

Institutions: University of North Carolina at Chapel Hill, UNC Lineberger Comprehensive Cancer Center

Language: English

Topic: Viral-associated cancers and disorders

Subfield: Oncology

Field: Medicine

Domain: Health Sciences

Open Access status: green

Funders: National Cancer Institute, National Institute of General Medical Sciences, National Institute of Allergy and Infectious Diseases

Awards: G1465922187, G1815638046, NRSA in Genetics, Molecular Biology of Viral Diseases Predoctoral Training Grant, Viral Oncogenesis, Latency, and Replication