Portal de Periódicos da CAPES

Characterization of an R-binding site mediating the R-induced activation of the Epstein-Barr virus BMLF1 promoter

1992; American Society for Microbiology; Volume: 66; Issue: 1 Linguagem: Inglês

10.1128/jvi.66.1.46-52.1992

1098-5514

Henri Gruffat, Nathalie Duran, Monique Buisson, Fabian Wild, Robin Buckland, Alain Sergeant,

Eosinophilic Disorders and Syndromes

In cells latently infected with Epstein-Barr virus, the switch from latency to productive infection is linked to the expression of two Epstein-Barr virus transcription factors called EB1 and R. R is an enhancer factor, and an R-responsive element (RRE) has been identified in the BMLF1 promoter. In this study, we have used bidirectional deletion mutagenesis to delineate the BMLF1 RRE (RRE-M) to a 44-bp sequence. We also show that R expressed from a recombinant vaccinia virus protects RRE-M against digestion by DNase I. Using mobility shift assays and dimethyl sulfate interferences, we have characterized the contact points between in vitro-translated R and the DNA. R binds in vitro to one site by simultaneously contacting two sequences within the site, which are separated by 8 bp: 5'-catGTCCCtctatcatGGCGCagac-3'. Site-directed mutagenesis of this sequence completely impaired the binding of R in vitro and rendered the BMLF1 promoter nonresponsive to R. The results suggest that the R-inducible BMLF1 enhancer is composed of a single R-binding site, called RRE-M.