Shrimp miR-10a Is Co-opted by White Spot Syndrome Virus to Increase Viral Gene Expression and Viral Replication.

Jiun-Yan Huang,Shih-Shun Lin,Li-Kwan Chang,Guang-Hsiung Kou,I-Tung Chen,Shih-Ting Kang,Chia-Ying Chu,Chu-Fang Lo

doi:10.3389/fimmu.2017.01084

Jiun-Yan Huang, Shih-Shun Lin + Show 6 more

Open Access

https://doi.org/10.3389/fimmu.2017.01084

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Abstract

Members of the microRNA miR-10 family are highly conserved and play many important roles in diverse biological mechanisms, including immune-related responses and cancer-related processes in certain types of cancer. In this study, we found the most highly upregulated shrimp microRNA from Penaeus vannamei during white spot syndrome virus (WSSV) infection was miR-10a. After confirming the expression level of miR-10a by northern blot and quantitative RT-PCR, an in vivo experiment showed that the viral copy number was decreased in miR-10a-inhibited shrimp. We found that miR-10a targeted the 5′ untranslated region (UTR) of at least three viral genes (vp26, vp28, and wssv102), and plasmids that were controlled by the 5′ UTR of these genes produced enhanced luciferase signals in transfected SF9 cells. These results suggest a previously unreported role for shrimp miR-10a and even a new type of host–virus interaction, whereby a co-opts the key cellular regulator miR-10a to globally enhance the translation of viral proteins.

Highlights

MicroRNAs are short, non-coding, endogenous RNAs with a length of 17–25 nucleotides. They are involved in posttranscriptional regulation, which they usually achieve by targeting the untranslated regions (UTR) of an mRNA [1,2,3]. miRNAs are key regulators and play an important role in diverse biological systems, including cell proliferation, cell differentiation, metabolism, development, apoptosis, and host–pathogen interactions [4, 5]
After using next-generation sequencing (NGS) technology to identify differentially expressed shrimp miRNAs in the stomachs of white spot syndrome virus (WSSV)-infected Penaeus vannamei, we focus on miR-10a, which was the most highly expressed host miRNA after WSSV infection. miR-10a is a member of the highly conserved miR-10 family [26], and unexpectedly, instead of inhibiting viral replication by targeting the 3′ UTR of viral genes, this host miRNA promotes viral replication by directly targeting the 5′ UTR of at least three viral genes to enhance their translation
We show that the shrimp microRNA miR-10a enhances the expression of WSSV structural and nonstructural proteins by targeting the 5′ UTR of the viral mRNAs

Summary

Introduction

MicroRNAs (miRNAs) are short, non-coding, endogenous RNAs with a length of 17–25 nucleotides (nt). They are involved in posttranscriptional regulation, which they usually achieve by targeting the untranslated regions (UTR) of an mRNA [1,2,3]. Recent studies have demonstrated that viral infection can alter the expression of cellular miRNA species in the cells of the host, and large changes in the expression of cellular miRNAs can impact virus replication either directly by targeting viral nucleic acid sequences [6,7,8,9,10] or else indirectly by targeting cellular mRNAs [11, 12]. Shrimp white spot syndrome virus (WSSV) encodes more than a 100 viral miRNAs, and most of these are expressed from the early stage of viral infection [13].

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