Role of Notch signal transduction in Kaposi's sarcoma-associated herpesvirus gene expression.
Kaposi's sarcoma-associated herpesvirus (KSHV) RTA transcription factor is recruited to its responsive elements through interaction with a Notch-mediated transcription factor, RBP-Jkappa, indicating that RTA mimics cellular Notch signal transduction to activate viral lytic gene expression. To test whether cellular Notch signal transduction and RTA are functionally exchangeable for viral gene expression, human Notch intracellular (hNIC) domain that constitutively activates RBP-Jkappa transcription factor activity was expressed in KSHV-infected primary effusion lymphoma BCBL1 cells (TRExBCBL1-hNIC) in a tetracycline-inducible manner. Gene expression profiling showed that like RTA, hNIC robustly induced expression of a number of viral genes, including viral interleukin 6 (vIL-6), K3, and K5. Unlike RTA, however, hNIC was not capable of evoking the full repertoire of lytic viral gene expression and thereby lytic replication. To further understand the role of Notch signal transduction in KSHV gene expression, vIL-6 growth factor and K5 immune modulator genes were selected for detailed analysis. Despite the presence of multiple RBP-Jkappa binding sites, hNIC targeted the specific RBP-Jkappa binding sites of vIL-6 and K5 promoter regions to regulate their gene expression. These results indicate that cellular Notch signal transduction not only is partially exchangeable with RTA in regard to activation of viral lytic gene expression but also provides a novel expression profile of KSHV growth and immune deregulatory genes that is likely different from that of RTA-independent standard latency program as well as RTA-dependent lytic reproduction program.
Chang
Heesoon
H
Department of Microbiology and Molecular Genetics and Tumor Virology Division, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts 01772, USA.
Dittmer
Dirk P
DP
Shin
Young C
YC
Chul
Shin-Young
SY
Hong
Youngkwon
Y
Jung
Jae U
JU
D002460:Cell Line; D002843:Chromatin / Q000235:genetics; D017931:DNA Primers; D015967:Gene Expression Regulation, Viral; D017930:Genes, Reporter; D016679:Genome, Viral; D006564:Herpesviridae / Q000235:genetics*; D019288:Herpesvirus 8, Human / Q000235:genetics; D006801:Humans; D007700:Kinetics; D011956:Receptors, Cell Surface / Q000502:physiology; D045522:Recombinases / Q000502:physiology; D012514:Sarcoma, Kaposi / Q000821:virology*; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection
D002843:Chromatin; D017931:DNA Primers; D011956:Receptors, Cell Surface; D045522:Recombinases