The identification of new transcription elements active in Epstein-Barr virus latent gene expression

The immortalization in vitro of human B cells by the Epstein-Barr virus (EBV) is associated with the expression of a restricted group of nuclear proteins (EBNA). EBNA transcription is driven from either of two mutually exclusive promoters whose modulation is likely to involve an important host/virus interaction. Our experiments on the EBNA transcriptional domain have led us to identify several new transcription elements which are located on the DNA sequence between the two promoters. These elements stimulate the activity of the upstream EBNA promoter by a factor of at least one hundred. One of these elements may also be involved in the in vivo reactivation of EBV in certain cases.