Early and sustained expression of latent and host modulating genes in coordinated transcriptional program of KSHV productive primary infection of human primary endothelial cells

Coordinated expression of viral genes in primary infection is essential for successful infection of host cells. We examined the expression profiles of Kaposi's sarcoma-associated herpesvirus (KSHV) transcripts in productive primary infection of primary human umbilical vein endothelial cells by whole-genome reverse-transcription real-time quantitative PCR. The latent transcripts were expressed early and sustained at high levels throughout the infection while the lytic transcripts were expressed in the order of immediate early, early, and lytic transcripts, all of which culminated before the production of infectious virions. Significantly, transcripts encoding genes with host modulating functions, including mitogenic and cell cycle-regulatory, immune-modulating, and anti-apoptotic genes, were expressed before those encoding viral structure and replication genes, and sustained at high levels throughout the infection, suggesting KSHV manipulation of host environment to facilitate infection. The KSHV transcriptional program in a primary infection defined in this study should provide a basis for further investigation of virus-cell interactions.