Expression Profiling of Cellular Genes Modulated by Kaposi’s Sarcoma Associated Herpesvirus (KSHV) RTA/ORF50 in HEK293 Cells

KSHV RTA (K-RTA) is a transcriptional activator that functions to disrupt KSHV latency and activates specific sets of viral promoters in the lytic cycle. Structure-function studies indicate that K-RTA possesses a very potent transactivation domain locating at the C-terminus. To further characterize the biological functions of K-RTA, we have established three doxycycline-inducible K-RTA 293 cell lines using RevTRE/Tet-On system (Clontech). Comparing to two control lines in which K-RTA was replaced with luciferase reporter, a total of 88 host genes were identified to be modulated by 24 h doxycycline-induced K-RTA synthesized in 293 cells. Designations for the three K-RTA inducible cell lines are KRta_92, KRta_116 and KRta_124; for the control line is RevTRE_Luc_1. All the four inducible cell lines were grown to log-phase before doxycycline induction. Same number of cells from the four cell lines were treated with doxycycline for 24 h . One duplicate of control RevTRE_Luc_1 was left untreated for inducer control. Total RNAs from the five samples were extracted and subjected to microarray analysis (Affymetrix HG-U133A, n=22,283). We sought to identify genes up- or down-regulated in the three doxycycline-treated K-RTA cells, but not in the treated or untreated RevTRE_Luc_1 cells.