KSHV RTA induces a transcriptional repressor, HEY1 that represses rta promoter.
Kaposi's sarcoma-associated herpesvirus (KSHV) is a gamma-herpesvirus that is frequently associated with the formation of tumors like Kaposi's sarcoma and primary effusion lymphomas. KSHV RTA is required for lytic replication/reactivation in KSHV-infected cells. We developed an inducible RTA expression cell line to search for RTA-inducible genes. Using DNA chip technology, we showed that hey1, a basic helix-loop-helix-containing transcription factor, increased three- to fourfold in this line. In a luciferase reporter system, RTA activated the hey1 promoter in several cell lines; conversely, HEY1 repressed the rta promoter. Chromatin immunoprecipitation assays indicated that HEY did not bind the rta promoter directly, although it may repress rta expression as part of a complex. Thus, hey1 may help to downregulate RTA after its burst of expression during lytic replication/reactivation. Similar repression mechanisms may downregulate immediate-early gene expression in other herpesviruses, although different transcription factors are probably involved.
Yada
Kaori
K
Department of Microbiology, Osaka University Medical School, Suita, Osaka 565-0871, Japan.
Do
Eunju
E
Sakakibara
Shuhei
S
Ohsaki
Eriko
E
Ito
Emi
E
Watanabe
Shinya
S
Ueda
Keiji
K