Different viral silencing suppressors interact with RRP6-like exoribonucleases which in turn bind components of RNA silencing machinery

FREIRE MA

Buenos Aires

Workshop; Workshop Biologia Molecular y Celular del ARN; 2018

Club del ARN (Argentina)

RNA decay and post-transcriptional gene silencing are functionally interlaced, down-regulate gene expression and play a pivotal role in antiviral responses. As a counter defensive strategy most viruses encode silencing suppressors to interfere with the host cell silencing mechanisms. On the other hand, recent studies have implicated the exosome components as viral targets. Nonetheless, a detailed knowledge of interactions between the components of these pathways is unknown.A previous study reported that potyviral silencing suppressor HC-Pro and VPg from different potyviruses interacted with the tobacco C-terminal regions of an RRP6-like protein that is an auxiliary factor of RNA exosome complex involved in RNA decay, and a small Heat shock protein (Hsp). Translation initiation factors eIF(iso)4E which are key components of recessive resistance and susceptibility mainly in plant-potyvirus interactions were also found to interact with the C-terminal regions of tobacco and Arabidopsis RRP6L1, and the Hsp (Freire 2014).Here, using a candidate search approach based on protein interaction assays it was shown that other unrelated viral suppressors also bind RRP6L proteins at its C-terminal regions and the other host factors. In addition, a physical link between RNA surveillance pathways and RNA silencing mechanisms was identified. The exosomal RRP6L proteins were found to bind components of RNA silencing machinery.These findings suggest a network of protein interactions involving different viral silencing suppressors, translation initiation factors eIF(iso)4E, exoribonuclease Rrp6, Hsp, and components of RNA silencing with possible implications on RNA decay and RNA silencing pathways.