Molecular cloning and characterization of Mj-mov-10, a putative RNA helicase involved in RNAi of kuruma shrimp

• The full-length Mj-mov-10 gene contained 3536 bp encoding 964 amino acids.
• An ORF of Mj-mov-10 consists of a single helicase core domain.
• Expression of Mj-mov-10 gene was significantly up-regulated upon dsRNA and WSSV challenge.
• Knockdown of Mj-mov-10 resulted in an increase of a susceptibility of shrimp to WSSV infection.

Identification and characterization of the RNAi-related genes is the key to understanding RNAi mechanism in shrimp. In this study, we have identified and characterized a novel putative RNA helicase gene, Mj-mov-10 from the kuruma shrimp, Marsupenaeus japonicus and its implication in shrimp RNAi was demonstrated. The full-length Mj-mov-10 gene contained 3536 bp, including 239 bp of 5′UTR, 2895 bp of the open reading frame (ORF) and 402 bp of 3′UTR, respectively. An ORF of Mj-mov-10 could be translated to a 109-kDa protein which consists of a single helicase core domain containing seven signature motifs of the RNA helicase superfamily-1. Mj-MOV-10 protein shared 47% and 40% identity with mammalian MOV-10 and plant SDE3, respectively. Expression of Mj-mov-10 gene was significantly up-regulated upon dsRNA and white spot syndrome virus (WSSV) challenge. In vivo gene knockdown of Mj-mov-10 resulted in an increase of a susceptibility of shrimp to WSSV infection. Our results implied the functional significance of Mj-MOV-10 in dsRNA-mediated gene silencing and antiviral defense mechanism in shrimp.