Host MicroRNA-217 Promotes White Spot Syndrome Virus Infection by Targeting Tube in the Chinese Mitten Crab (Eriocheir sinensis)

Abstract

MicroRNAs (miRNAs), a group of small molecule non-encoding RNAs, are key post-transcriptional regulators of gene expression that are implicated in many biological processes. In the current study, miR-217 from <i>Eriocheir sinensis</i> was selected for studying its roles during host-virus interaction. Overexpression or silencing of miR-217 led to considerable effects on white spot syndrome virus (WSSV) replication, implying that miR-217 played a positive role in WSSV infection. In insect High Five cells, miR-217 significantly inhibited <i>Tube</i> gene expression by binding to the 3'-untranslated region of the <i>Tube</i>. Overexpression of miR-217 in crab led to downregulation of <i>tube</i> expression. Knockdown of <i>Tube in vivo</i> led to significant enhancement of WSSV infection and inhibited the expression of five <i>antimicrobial peptide</i> (<i>AMP</i>) genes (<i>Anti-lipopolysaccharide factor ALF1, ALF2, ALF3</i>; <i>Crustin Crus1, Crus2</i>) in WSSV-challenged crabs. Overexpression of miR-217 also led to downregulation of these <i>AMP</i> genes in WSSV-challenged crabs. Our results showed that host miRNA played positive roles in virus infection by regulation of host <i>tube</i> gene, which is the key component of Toll signaling pathway.