Activation of T-cell-factor-dependent transcription by Kaposi's sarcoma-associated herpesvirus replication transactivation activator.
OBJECTIVE
To elucidate the cellular function of Kaposi's sarcoma-associated herpesvirus (KSHV) replication transactivation activator (RTA) at the transcriptional level.


METHODS
Transcriptional activation of T-cell-factor (TCF)-dependent genes by RTA was determined using the luciferase reporter assay. The specific regions of RTA required for the activation of TCF-dependent transcription and association with β-catenin were established.


RESULTS
RTA specifically activated TCF-dependent transcription in a dose-dependent manner, to an extent comparable to the activation achieved by latency-associated nuclear antigen. In contrast, other KSHV viral proteins investigated, such as basic leucine zipper and viral interferon regulatory factor 1, did not affect TCF-dependent transcription. The C-terminal region of RTA appeared to be necessary for transcription. However, RTA did not affect the β-catenin level or the subcellular localization thereof.


CONCLUSIONS
Our results collectively demonstrate that KSHV RTA activates TCF-dependent transcription without involving the β-catenin pathway.
Cha
Seho
S
Department of Life Science, Dongguk University-Seoul, Seoul, South Korea.
Yoon
Hee Jung
HJ
Kim
Su-Jung
SJ
Seo
Taegun
T
D002460:Cell Line; D017930:Genes, Reporter; D019288:Herpesvirus 8, Human / Q000502:physiology*; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D025941:Protein Interaction Mapping; D013601:T-Lymphocytes / Q000821:virology*; D051820:TCF Transcription Factors / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic; D014779:Virus Replication; D051176:beta Catenin / Q000378:metabolism
D017874:Immediate-Early Proteins; C417604:Rta protein, Human herpesvirus 8; D051820:TCF Transcription Factors; D015534:Trans-Activators; D051176:beta Catenin; D008156:Luciferases