RNase SFB textbausteine

intro viruses and rna decay machinery

pmid: 17375004 - RNA viruses perhaps associate more intimately with the cellular RNA decay machinery given the nature of their genomes. Like their DNA virus counterparts, several strategies have been identified by which the viruses evade detection of the RNA monitoring activities of the host. These strategies can generally be separated into two groups, those that rely on physical exclusion of the decay machinery, and those that modulate the function of the host decay machinery.Viral mRNP structure and subcellular localization may play important roles in the evasion of the cellular RNA decay machinery. RNA viruses package their genome in nucleocapsid protein structures capable of physically obscuring the RNAs from cellular detection. The reoviruses are an excellent example as they shield their dsRNA genome from cellular detection by incorporation into RNP structures formed from the capsid subunits, thereby preventing the activation of the host dsRNA response.6 Evidence has also suggested that in some cases replication is associated with the formation of membranous subcellular structures or compartments.7 It is reasonable to suggest that this alternative localization may serve not only to increase the local concentration of viral effectors, but also to obscure the viral RNA from the cytoplasmic decay machinery. These novel RNPs and cellular compartments may on their own be sufficient to thwart the mRNA decay machinery and reduce its overall influence on virus growth. However it should be stressed that in order to express their genetic information, viral RNAs must eventually be uncoated and localized in conventional cellular compartments in order to utilize the cellular translation machinery. Therefore while RNP structure and localization may contribute to viral RNA stability, they cannot be the whole story.

modulation of decay enzymes by vProteins and vRNA sequences/structures