Non-canonical translation in plant RNA viruses


Publication Type:

Journal Article


Front. Plant Sci., Volume 8 (2017)


<p>Viral protein synthesis is completely dependent upon the host cell’s translational<br />
machinery. Canonical translation of host mRNAs depends on structural elements such<br />
as the 5′ cap structure and/or the 3′ poly(A) tail of the mRNAs. Although many viral<br />
mRNAs are devoid of one or both of these structures, they can still translate efficiently<br />
using non-canonical mechanisms. Here, we review the tools utilized by positive-sense<br />
single-stranded (+ss) RNA plant viruses to initiate non-canonical translation, focusing<br />
on cis-acting sequences present in viral mRNAs. We highlight how these elements may<br />
interact with host translation factors and speculate on their contribution for achieving<br />
translational control. We also describe other translation strategies used by plant viruses<br />
to optimize the usage of the coding capacity of their very compact genomes, including<br />
leaky scanning initiation, ribosomal frameshifting and stop-codon readthrough. Finally,<br />
future research perspectives on the unusual translational strategies of +ssRNA viruses<br />
are discussed, including parallelisms between viral and host mRNAs mechanisms of<br />
translation, particularly for host mRNAs which are translated under stress conditions.</p>