The zinc finger DNA-binding domain of K-RBP plays an important role in regulating Kaposi's sarcoma-associated herpesvirus RTA-mediated gene expression.
K-RBP is a KRAB-containing zinc finger protein with multiple zinc finger motifs and represses Kaposi's sarcoma-associated herpesvirus (KSHV) transactivator RTA-mediated transactivation of several viral lytic gene promoters, including the ORF57 promoter. Whether K-RBP binds DNA through its zinc fingers and the role of zinc finger domain in repressing gene expression are unclear. Here we report that K-RBP binds DNA through its zinc finger domain and the target DNA sequences contain high GC content. Furthermore, K-RBP binds to KSHV ORF57 promoter, which contains a GC-rich motif. K-RBP suppresses the basal ORF57 promoter activity as well as RTA-mediated activation. The zinc finger domain of K-RBP is sufficient for the suppression of ORF57 promoter activation mediated by the viral transactivator RTA. Finally, we show that K-RBP inhibits RTA binding to ORF57 promoter. These findings suggest that the DNA-binding activity of K-RBP plays an important role in repressing viral promoter activity.
Yang
Zhilong
Z
Nebraska Center for Virology and School of Biological Sciences, University of Nebraska-Lincoln, Lincoln NE 68583, USA.
Wen
Hui-Ju
HJ
Minhas
Veenu
V
Wood
Charles
C
D004279:DNA, Viral / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D019288:Herpesvirus 8, Human / Q000502:physiology*; D017874:Immediate-Early Proteins / Q000037:antagonists & inhibitors*; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000378:metabolism*; D015534:Trans-Activators / Q000037:antagonists & inhibitors*; D016335:Zinc Fingers
D004279:DNA, Viral; D017874:Immediate-Early Proteins; D012097:Repressor Proteins; C417604:Rta protein, Human herpesvirus 8; D015534:Trans-Activators; C520977:ZNF426 protein, human