Mapping of two varicella-zoster virus-encoded genes that activate the expression of viral early and late genes.
A transient assay system was used to identify varicella-zoster virus (VZV)-encoded genes whose products are able to activate the expression of an early gene promoter, the thymidine kinase (tk) promoter, and a late gene promoter, and the glycoprotein I (gpI) promoter. Vero cells were cotransfected with individual cloned DNA fragments spanning the entire VZV genome and with the recombinant construct p1tkCAT which contained the chloramphenicol acetyl transferase (CAT) gene under the control of putative regulatory sequences. Five- to 20-fold increases in the expression p1tkCAT was observed in cotransfections with plasmids containing VZV open reading frame (ORF)4 (map location 0.02-0.03) or ORF62 (0.82-0.86). Expression of p68CAT (contains -682 to +222 bp relative to the AUG of gpI) was also enhanced by the products of ORF4 and ORF62. Synergy between ORF4 and ORF62 products was observed in the activation of p68CAT, resulting in a 22-fold increase in CAT activity. RNA analysis indicated that activation of these promoters was at the transcriptional level. A VZV-encoded "repressor" sequence, containing ORF60 and ORF61, was also identified which repressed expression of p1tkCAT and modulated its activation by ORF4 and ORF62.
Inchauspe
G
G
Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Nagpal
S
S
Ostrove
J M
JM
D000818:Animals; D003001:Cloning, Molecular; D015967:Gene Expression Regulation, Viral; D006023:Glycoproteins / Q000235:genetics*; D014645:Herpesvirus 3, Human / Q000201:enzymology / Q000235:genetics*; D006801:Humans; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000032:analysis; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013937:Thymidine Kinase / Q000235:genetics*; D015533:Transcriptional Activation; D014162:Transfection; D014709:Vero Cells
D006023:Glycoproteins; D012367:RNA, Viral; D013937:Thymidine Kinase