The brome mosaic virus 3′ untranslated sequence regulates RNA replication, recombination, and virion assembly

• The 3′ tRNA-like structure (3′TLS) conserved among three genomic RNAs of brome mosaic virus is multifunctional.
• BMV TLS harbors recognition signals for minus-strand initiation by viral RdRp.
• BMV TLS functions in RNA recombination and as a nucleation motif for virion assembly.

The 3′ untranslated region in each of the three genomic RNAs of Brome mosaic virus (BMV) is highly homologous and contains a sequence that folds into a tRNA-like structure (TLS). Experiments performed over the past four decades revealed that the BMV 3′ TLS regulates many important steps in BMV infection. This review summarizes in vitro and in vivo studies of the roles of the BMV 3′ TLS functioning as a minus-strand promoter, in RNA recombination, and to nucleate virion assembly.