Identification of a Cellular Protein That Interacts and Synergizes with the RTA (ORF50) Protein of Kaposiâ•Žs Sarcoma-Associated Herpesvirus in Transcriptional Activation

Identification of a cellular protein that interacts and synergizes with the RTA (ORF50) protein of Kaposi's sarcoma-associated herpesvirus in transcriptional activation.

Lytic reactivation of Kaposi's sarcoma-associated herpesvirus (KSHV), or human herpesvirus 8, from latency requires transcriptional transactivation by the viral protein RTA encoded by the ORF50 gene. Very little is known about how RTA functions and the cellular factors that may be involved in its transactivation function. Using the yeast two-hybrid system, we have identified a human cellular pr...

The Transcriptional Repressor K-RBP Modulates RTA-Mediated Transactivation and Lytic Replication of Kaposiâ•Žs Sarcoma-Associated Herpesvirus

Kaposi's Sarcoma-associated herpesvirus open reading frame 50 stimulates the transcriptional activity of STAT3.

Kaposi's sarcoma-associated herpesvirus (KSHV) is an important pathogen in Kaposi's sarcoma and abnormal lymphoproliferation. KSHV open reading frame 50 (ORF50), a homolog of the Epstein-Barr virus immediate-early gene product RTA, activates early and late gene transcription in the KSHV lytic cycle, and its expression is closely correlated with KSHV-related diseases. ORF50 interacts with the ce...

Comparison of the Rta/Orf50 transactivator proteins of gamma-2-herpesviruses.

The viral immediate-early transactivator Rta/Orf50 is necessary and sufficient to initiate Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8) reactivation from latently infected cells. Since Rta/Orf50 is conserved among all known gamma-2-herpesviruses, we investigated whether the murine gamma-68-herpesvirus (MHV-68) and rhesus monkey rhadinovirus (RRV) homologs can functio...

Acetylation of the latency-associated nuclear antigen regulates repression of Kaposi's sarcoma-associated herpesvirus lytic transcription.

Reactivation of the Kaposi's sarcoma-associated herpesvirus (KSHV) lytic cycle can be initiated by transcription activation of the ORF50 immediate early gene (Rta). We show that ORF50 transcription is actively repressed by the KSHV latency-associated nuclear antigen (LANA) during latency. Depletion of LANA by small interfering RNA derepressed ORF50 transcription in the latently infected BCBL1 p...