Bovine Leukemia virus antisense transcription is required for efficient replication in vivo

Abstract

The Bovine leukemia virus (BLV) is an oncogenic deltaretrovirus that induces enzootic bovine leukosis. Most of the infected bovines are asymptomatic, but after a long latency period, approximately 5% of them end up developing a leukemia/lymphoma. How the virus promotes the evolution of the disease is still not fully understood. Nevertheless, recently discovered antisense RNAs (AS1-S/L and AS2) are likely to have an important role in viral propagation and malignancy. The aim of work is to assess the involvement of antisense transcription in viral infectivity, replication and B cell homeostasis. Based on a reverse genetics approach, results show that a two base pair mutation in the promoter sequence affects negatively viral antisense transcripts levels in vitro, and that viral replication, in contrast to infectivity, requires expression of antisense RNAs in vivo.