Virus Replication
Plant RNA Viruses
Replication of Plant RNA Viruses
from Peter D. Nagy and Judit Pogany writing in Recent Advances in Plant Virology
Among plant viruses, the positive-stranded RNA [(+)RNA] viruses are the largest group, and the most widespread. The central step in the infection cycle of (+)RNA viruses is RNA replication, which is carried out by virus-specific replicase complexes consisting of viral RNA-dependent RNA polymerase, one or more auxiliary viral replication proteins, and a number of co-opted host factors. Viral replicase complexes assemble in specialized membranous compartments in infected cells. Sequestering the replicase complexes is not only helpful for rapid production of a large number of viral (+)RNA progeny, but it also facilitates avoiding recognition by the host¹s anti-viral surveillance system, and it provides protection from degradation of the viral RNA. Successful viral replication is followed by cell-to-cell and long-distance movement throughout the plant, as well as encapsidation of the (+)RNA progeny to facilitate transmission to new plants. A recent review provides an overview of our current understanding of the molecular mechanisms in plant (+)RNA virus replication. Recent significant progress in this research area is based on development of powerful in vivo and in vitro methods, including replicase assays, reverse genetic approaches, intracellular localization studies, genome-wide screens for co-opted host factors and the use of plant or yeast model hosts.
Further reading: Recent Advances in Plant Virology | Virology Publications | RNA and the Regulation of Gene Expression
from Peter D. Nagy and Judit Pogany writing in Recent Advances in Plant Virology
Among plant viruses, the positive-stranded RNA [(+)RNA] viruses are the largest group, and the most widespread. The central step in the infection cycle of (+)RNA viruses is RNA replication, which is carried out by virus-specific replicase complexes consisting of viral RNA-dependent RNA polymerase, one or more auxiliary viral replication proteins, and a number of co-opted host factors. Viral replicase complexes assemble in specialized membranous compartments in infected cells. Sequestering the replicase complexes is not only helpful for rapid production of a large number of viral (+)RNA progeny, but it also facilitates avoiding recognition by the host¹s anti-viral surveillance system, and it provides protection from degradation of the viral RNA. Successful viral replication is followed by cell-to-cell and long-distance movement throughout the plant, as well as encapsidation of the (+)RNA progeny to facilitate transmission to new plants. A recent review provides an overview of our current understanding of the molecular mechanisms in plant (+)RNA virus replication. Recent significant progress in this research area is based on development of powerful in vivo and in vitro methods, including replicase assays, reverse genetic approaches, intracellular localization studies, genome-wide screens for co-opted host factors and the use of plant or yeast model hosts.
Further reading: Recent Advances in Plant Virology | Virology Publications | RNA and the Regulation of Gene Expression
Translation of Viral RNAs
Roles of Cis-acting Elements in Translation of Viral RNAs
from W. Allen Miller, Jelena Kraft, Zhaohui Wang and Qiuling Fan writing in Recent Advances in Plant Virology
Cis-acting signals regulate translation of viral RNAs to produce viral proteins at the appropriate levels and timing to maximize virus replication. A recent review describes the cis-acting sequences that achieve this translational control via processes such as cap-dependent translation, leaky scanning to initiate translation at more than one start codon, ribosomal shunting, cap-independent translation initiation controlled from the 5' and/or 3' untranslated region, poly(A) tail-independent translation initiation, stop codon readthrough, and ribosomal frameshifting. Secondary structures and, in some cases, tertiary structures of the RNA sequences control these events and translation events facilitated by the cis-acting signals mesh with the overall replication strategies of the diverse viruses that employ these mechanisms.
Further reading: Recent Advances in Plant Virology | Virology Publications
from W. Allen Miller, Jelena Kraft, Zhaohui Wang and Qiuling Fan writing in Recent Advances in Plant Virology
Cis-acting signals regulate translation of viral RNAs to produce viral proteins at the appropriate levels and timing to maximize virus replication. A recent review describes the cis-acting sequences that achieve this translational control via processes such as cap-dependent translation, leaky scanning to initiate translation at more than one start codon, ribosomal shunting, cap-independent translation initiation controlled from the 5' and/or 3' untranslated region, poly(A) tail-independent translation initiation, stop codon readthrough, and ribosomal frameshifting. Secondary structures and, in some cases, tertiary structures of the RNA sequences control these events and translation events facilitated by the cis-acting signals mesh with the overall replication strategies of the diverse viruses that employ these mechanisms.
Further reading: Recent Advances in Plant Virology | Virology Publications