Inhibition of expression of BmNPV cg30 by bmo-miRNA-390 is a host response to baculovirus invasion

Abstract

Bombyx mori larvae exhibit in vivo defensive reactions immediately after invasion by a virus. One of these defense systems is to express appropriate microRNAs (miRNAs) to respond to the infection. A novel Bombyx mori-encoded miRNA, bmo-miR-390, was identified previously by high-throughput sequencing. Based on bioinformatic predictions, the Bombyx mori nuclear polyhedrosis virus cg30 gene (BmNPV-cg30) is one of the target genes of bmo-miR-390. In this study, expression vectors with an enhanced green fluorescence protein (EGFP) or a luciferase (luc) reporter gene together with bm-miR-390 or the cg30 3' UTR were constructed and used to co-transfect BmN cells. Using a dual luciferase reporter (DLR) assay, we found that bmo-miR-390 significantly downregulates the expression of BmNPV-cg30 (P < 0.05) in vitro. Moreover, artificially synthesized bmo-miR-390 mimics enhanced the regulatory effect of bmo-miR-390, while an inhibitor eliminated the inhibitory effect. These results show for the first time that bmo-miR-390 can effectively downregulate the expression of BmNPV-cg30 in BmNPV-infected BmN cells.

Advances in the Arms Race Between Silkworm and Baculovirus

“…The silkworm-encoded miRNA bmo-miR-2819 is upregulated at the delayed early stage in infection, and its overexpression inhibits BmNPV proliferation by downregulating viral ie-1 ( 66 ). Similarly, bmo-miRNA-390 downregulates the expression of BmNPV- cg30 ( 67 ). The PIWI-associated RNA (piRNA) pathway is also involved in an antiviral response but little information is reported in silkworm ( 68 ).…”

MicroRNA-Mediated Host Immune Genes Manipulation Benefits AcMNPV Proliferation in Spodoptera frugiperda

“…In BmNPV-infected larvae, 38 DEmiRNAs were identified to be involved in several functions, including innate immune responses . Several viral genes, including odv-e18 , orf118 , me53 , orf98a p43, etc., were predicted to be potential targets of the B. mori miRNA, bmo-miR-390 . Bantam miRNA is crucial in anti-AcMNPV responses in S. litura and S. exigua , where the inhibition of bantam increases the viral load and upregulated viral genes. , Investigations conducted in AcMNPV-infected Sf9 cells revealed the differential expression of numerous conserved and novel miRNAs .…”

Transcriptome of miRNA during inhibition of Bombyx mori nuclear polyhedrosis virus by geldanamycin in BmN cells

“…More and more studies had shown that miRNAs play key roles in host‐pathogen interactions by regulating the expression of host immune genes or viral genes, affecting viral replication (Chawla & Sokol, 2011; Kang et al, 2018; Mead & Tu, 2008; Padmanabhan et al, 2009; Simón‐Mateo & García, 2006). Studies have also confirmed that cellular miRNAs and viral miRNAs contribute to host immunity and host–pathogen interaction by regulating the expression of host or pathogen‐related genes in various organisms (Y. Li, Qin, et al, 2019; Ryan & Williams, 2019; Wu et al, 2013, 2016).…”