Binding of RBP-Jkappa (CSL) protein to the promoter of the Kaposi's sarcoma-associated herpesvirus ORF47 (gL) gene is a critical but not sufficient determinant of transactivation by ORF50 protein.
ORF50 protein activates the KSHV lytic cycle. The promoter of an early lytic-cycle gene ORF47, encoding envelope protein gL, is activated by an interaction between ORF50 protein and RBP-Jkappa. In ORF47p only one of two sequences fitting the consensus RBP-Jkappa recognition site strongly binds RBP-Jkappa and confers a response to ORF50 protein. Flanking sequences 5' to the RBP-Jkappa binding site are required to confer a maximal response to ORF50 protein. Not all mutant ORF50 response elements in the ORF47p that are bound by RBP-Jkappa are sufficient to confer maximal ORF50 responsiveness. Four sequences containing an RBP-Jkappa site and flanking sequences characteristic of the ORF50 response element in ORF47p were identified in human DNA. All bound RBP-Jkappa, but only one responded robustly to ORF50 protein. We propose models for the possible function of ancillary sequences flanking the RBP-Jkappa-binding element which are crucial for mediating ORF50 transactivation.
Chang
Pey-Jium
PJ
Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan, Taiwan.
Boonsiri
Joseph
J
Wang
Shih-Shan
SS
Chen
Li-Yu
LY
Miller
George
G
D045744:Cell Line, Tumor; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D019288:Herpesvirus 8, Human / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014779:Virus Replication / Q000502:physiology
D017874:Immediate-Early Proteins; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; C497570:RBPJ protein, human; C417604:Rta protein, Human herpesvirus 8; D015534:Trans-Activators