The Dietary Restriction-Like Gene drl-1 , Which Encodes a Putative Serine/Threonine Kinase, Is Essential for Orsay Virus Infection in Caenorhabditis elegans

Abstract

Orsay virus is the only known natural virus pathogen of Caenorhabditis elegans, and its discovery has enabled virus-host interaction studies in this model organism. Host genes required for viral infection remain understudied. We previously established a forward genetic screen based on a virus-inducible green fluorescent protein transcriptional reporter to identify novel host factors essential for virus infection. Here, we report the essential role in Orsay virus infection of the dietary restriction-like (drl-1) gene, which encodes a serine/threonine kinase similar to the mammalian MEKK3 kinase. Ablation of drl-1 led to a >10,000-fold reduction in Orsay virus RNA levels, which could be rescued by ectopic expression of DRL-1. DRL-1 was dispensable for Orsay replication from an endogenous transgene replicon, suggesting that DRL-1 affects a prereplication stage of the Orsay life cycle. Thus, this study demonstrates the power of C. elegans as a model to identify novel virus-host interactions essential for virus infection. IMPORTANCE The recent discovery of Orsay virus, the only known natural virus of Caenorhabditis elegans, provides a unique opportunity to study virus-host interactions that mediate infection in a genetically tractable multicellular model organism. As viruses remain a global threat to human health, better insights into cellular components that enable virus infection and replication can ultimately lead to the development of new targets for antiviral therapeutics.

Huntingtin-interacting protein family members have a conserved pro-viral function from Caenorhabditis elegans to humans

“…The two hipr-1 mutant alleles identified in this study phenocopy the viral replication and GFP induction defects observed in the previously identified essential C. elegans host gene mutant alleles sid-3 , viro-2 , and nck-1 ( 2 ). As the human orthologs of sid-3 , viro-2 , and nck-1 have since been demonstrated to function in a pathway ( 3 ), it is intriguing to speculate that hipr-1 may also be part of this pathway. However, as all mutant alleles represent null function for Orsay virus infection in C. elegans , any genetic endeavor to reveal their relationship remains challenging in C. elegans .…”

“…The multicellular model organism Caenorhabditis elegans is naturally infected by Orsay virus, a positive-sense, nonenveloped RNA virus ( 1 ). This infection system has recently been utilized to identify several novel host factors that are essential for Orsay virus infection ( 2 , 3 ). Through an unbiased forward genetic screen, the genes sid-3 , viro-2 , and drl-1 were previously identified as host factors essential at an early stage of the Orsay virus life cycle ( 2 , 3 ).…”

“…This infection system has recently been utilized to identify several novel host factors that are essential for Orsay virus infection ( 2 , 3 ). Through an unbiased forward genetic screen, the genes sid-3 , viro-2 , and drl-1 were previously identified as host factors essential at an early stage of the Orsay virus life cycle ( 2 , 3 ). This genetic screen utilized the jyIs8;rde-1(ne219) reporter strain, which expresses green fluorescent protein (GFP) under control of the virus-inducible gene promoter pals-5 ( 2 ).…”

“…C. elegans nck-1 is an additional critical factor for Orsay virus infection identified through an RNA interference (RNAi)-based reverse genetic screen targeting host factors interacting with the mammalian orthologs of sid-3 and viro-2 ( 2 ). Moreover, the human orthologs of sid-3 , viro-2 , and nck-1 ( TNK2 , WASP , and NCK1 , respectively) form a pathway that is important for infection by multiple viruses in the family Picornaviridae ( 3 ). In total, these studies establish that key pro-viral genes discovered in C. elegans may have evolutionarily conserved functions in mammals.…”

Natural variation in viral susceptibility of Caenorhabditis elegans

“…Table S4 Genes involved during OrV infection -Overview of C. elegans genes involved in OrV infection described in literature. Data is obtained from Bakowski et al 2014;Chen et al 2017;Félix et al 2011;Frézal et al 2019;Jiang et al 2017;Le Pen et al 2018;Reddy et al 2017Reddy et al , 2019Sandoval et al 2019;Sarkies et al 2013;Sowa et al 2019;Sterken et al 2014;Tanguy et al 2017).…”