MicroRNAs derived from the insect virus HzNV-1 promote lytic infection by suppressing histone methylation

Abstract

Heliothis zea nudivirus-1 (HzNV-1) is an insect virus that can induce both lytic and latent infections in various insect cell lines. During latent infection, several microRNAs (miRNAs) are produced from persistency-associated gene 1 (pag1) as the only detectable HzNV-1 transcript. Previous studies have shown that the pag1 gene suppresses the immediate-early gene hhi1 and promotes host switching into a latent infection via miRNAs derived from pag1. Although other functions of the miRNAs derived from pag1 have not yet been elucidated, several studies have suggested that miRNAs encoded from latency-associated genes can regulate histone-associated enzymes. Because pag1 is a noncoding transcript, it potentially regulates host chromatin structure through miRNAs upon infection. Nevertheless, the exact mechanism by which pag1 alters viral infections remains unknown. In this study, we found that the pag1-encoded miRNA miR-420 suppresses expression of the histone modification-associated enzyme su(var)3–9. Therefore, this miRNA causes histone modification to promote HzNV-1 infection. These results suggest that HzNV-1 may directly influence epigenetic regulation in host cells through interactions with pag1 miRNAs to promote lytic infection. This study provides us with a better understanding of both the HzNV-1 infection pathway and the relationship between viral miRNAs and epigenetic regulation.

Carbohydrate metabolism is a determinant for the host specificity of baculovirus infections

“…For analyzing gene expression in cell lines, SL1A or BmN cells infected with one of the viruses at a multiplicity of infection (MOI) of 1 were collected. RNA was extracted from larval tissues or cells using TRIzol reagent (Invitrogen) according to a previously described procedure ( Hu et al, 2018 ; Wu et al., 2018 ). Specifically, the tissue sample from two larvae or the cell sample (2 × 10 5 ) was lysed in 1 mL of TRIzol reagent.…”

Adenosine Receptor Modulates Permissiveness of Baculovirus (Budded Virus) Infection via Regulation of Energy Metabolism in Bombyx mori

“…Two third-instar larvae were pooled together for homogenization. OD values and RNA concentrations were detected using a microvolume spectrophotometer (Nanodrop 2000; Thermo Scientific) (24,25). cDNA was synthesized using the PrimeScript TM RT reagent kit (Takara).…”

Enhancing the insecticidal potential of a baculovirus by overexpressing the mammalian β‐galactosyl binding protein galectin‐1

“…The cell lysate was mixed with an equal volume of Laemmli sample buffer (Bio‐Rad, Hercules, CA, USA), and the sample was resolved in a 10% sodium dodecyl sulfate (SDS)‐polyacrylamide gel using Wet/Tank Blotting Systems (Bio‐Rad). The resolved sample was then transferred onto a polyvinylidene fluoride (PVDF) membrane (Millipore, Bedford, MA, USA) 27 . The expression of galectin‐1 was detected using either a rabbit anti‐6 × His antibody (LTK) or anti‐galectin‐1 antibody as the primary antibody, followed by a secondary goat anti‐rabbit immunoglobulin G (IgG) antibody (Merck, Darmstadt, Germany) or anti‐mouse IgG antibody.…”

“…The resolved sample was then transferred onto a polyvinylidene fluoride (PVDF) membrane (Millipore, Bedford, MA, USA). 27 The expression of galectin-1 was detected using either a rabbit anti-6 × His antibody (LTK) or anti-galectin-1 antibody as the primary antibody, followed by a secondary goat anti-rabbit immunoglobulin G (IgG) antibody (Merck, Darmstadt, Germany) or antimouse IgG antibody. Signals were detected using Western horseradish peroxidase (HRP) Substrate (Millipore) and quantified using UVP ChemStudio (Analytik Jena).…”