Latency of Epstein-Barr virus is stabilized by antisense-mediated control of the viral immediate-early gene BZLF-1

• Published in: Journal of medical virology 1999-12, Vol.59 (4), p.512-519
• Main Authors: Prang, Nadja, Wolf, Hans, Schwarzmann, Fritz
• Format: Article
• Language: English
• Subjects: Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiviral agents; B-lymphocyte; B-Lymphocytes; Biological and medical sciences; BZLF-1 gene; BZLF-1 protein; BZLF1 gene; BZLF1 protein; Cell Line; DNA-Binding Proteins - genetics; EBV; Epstein-Barr virus; Epstein-Barr Virus Nuclear Antigens - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Viral; Genetics; herpesvirus; Herpesvirus 4, Human - genetics; Herpesvirus 4, Human - physiology; lytic; Medical sciences; Microbiology; Pharmacology. Drug treatments; Plasmids - genetics; replication; Reverse Transcriptase Polymerase Chain Reaction; RNA Splicing; RNA, Antisense - physiology; RNA, Viral - physiology; Trans-Activators - genetics; Transcription, Genetic; Viral Proteins - genetics; Virology; Virus Latency - genetics; Virus Replication
• ISSN: 0146-6615; 1096-9071
• DOI: 10.1002/(SICI)1096-9071(199912)59:4<512::AID-JMV15>3.0.CO;2-B

The ability of the Epstein‐Barr virus (EBV) to avoid lytic replication and to establish a latent infection in B‐lymphocytes is fundamental for its lifelong persistence and the pathogenesis of various EBV‐associated diseases. The viral immediate‐early gene BZLF‐1 plays a key role for the induction of lytic replication and its activity is strictly regulated on different levels of gene expression. Recently, it was demonstrated that BZLF‐1 is also controlled by a posttranscriptional mechanism. Transient synthesis of a mutated competitor RNA saturated this mechanism and caused both expression of the BZLF‐1 protein and the induction of lytic viral replication. Using short overlapping fragments of the competitor, it is shown that this control acts on the unspliced primary transcript. RT‐PCR demonstrated unspliced BZLF‐1 RNA in latently infected B‐lymphocytes in the absence of BZLF‐1 protein. Due to the complementarity of the gene BZLF‐1 and the latency‐associated gene EBNA‐1 on the opposite strand of the genome, we propose an antisense‐mediated mechanism. RNase protection assays demonstrated transcripts in antisense orientation to the BZLF‐1 transcript during latency, which comprise a comparable constellation to other herpesviruses. A combined RNAse protection/RT‐PCR assay detected the double‐stranded hybrid RNA, consisting of the unspliced BZLF‐1 transcript and a noncoding intron of the EBNA‐1 gene. Binding of BZLF‐1 transcripts is suggested to be an important backup control mechanism in addition to transcriptional regulation, stabilizing latency and preventing inappropriate lytic viral replication in vivo. J. Med. Virol. 59:512–519, 1999. © 1999 Wiley‐Liss, Inc.