Fig 4.

Roles of host miR-7 in virus-host interactions. (a) Shrimp were injected simultaneously with WSSV and wsv477-siRNA or with WSSV and wsv477-mutation-siRNA, respectively. WSSV only was included in one of the injections. At 12 h postinfection, the shrimp were collected and subjected to Northern blot analysis to detect the wsv477 mRNA. Shrimp actin was used as a control. The probes are indicated on the right. (b) Western blots of shrimp gills with AP-conjugated goat anti-mouse IgGs. Shrimp actin was used as a control. The antibodies are indicated on the right. (c) The shrimp were injected simultaneously with WSSV and siRNA, miRNA, or LNA-modified anti-miRNA oligonucleotides. The solutions that were injected are shown at the top. At different times postinfection, the shrimp gill tissues were collected and subjected to real-time PCR to monitor the WSSV replication. The numbers indicate the time points postinfection. The statistically significant differences between treatments are represented with asterisks (*, P < 0.05; **, P < 0.01). (d) Proposed model for the role of miR-7 in virus-host interactions. Host miR-7 was generated in a Dicer1-dependent manner and decreased the transcript levels of viral early gene wsv477 by directly targeting the 3′UTR of wsv477 mRNA. The Dicer1-miR-7-wsv477 pathway was assumed to be involved in WSSV infection.