title: Characterization of host microRNAs that respond to DNA virus infection in a crustacean.
abstract: BACKGROUND
  MicroRNAs (miRNAs) are key posttranscriptional regulators of gene expression that are implicated in many processes of eukaryotic cells. It is known that the expression profiles of host miRNAs can be reshaped by viruses. However, a systematic investigation of marine invertebrate miRNAs that respond to virus infection has not yet been performed.
  
  
  RESULTS
  In this study, the shrimp Marsupenaeus japonicus was challenged by white spot syndrome virus (WSSV). Small RNA sequencing of WSSV-infected shrimp at different time post-infection (0, 6, 24 and 48 h) identified 63 host miRNAs, 48 of which were conserved in other animals, representing 43 distinct families. Of the identified host miRNAs, 31 were differentially expressed in response to virus infection, of which 25 were up-regulated and six down-regulated. The results were confirmed by northern blots. The TargetScan and miRanda algorithms showed that most target genes of the differentially expressed miRNAs were related to immune responses. Gene ontology analysis revealed that immune signaling pathways were mediated by these miRNAs. Evolutionary analysis showed that three of them, miR-1, miR-7 and miR-34, are highly conserved in shrimp, fruit fly and humans and function in the similar pathways.
  
  
  CONCLUSIONS
  Our study provides the first large-scale characterization of marine invertebrate miRNAs that respond to virus infection. This will help to reveal the molecular events involved in virus-host interactions mediated by miRNAs and their evolution in animals.
authors.affiliation: Key Laboratory of Conservation Biology for Endangered Wildlife of Ministry of Education, Key Laboratory of Animal Virology of Ministry of Agriculture and College of Life Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China.
authors.forename: Tianzhi
authors.initials: T
authors.lastname: Huang
authors.forename: Dandan
authors.initials: D
authors.lastname: Xu
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000465:Algorithms; D000818:Animals; D015536:Down-Regulation; D020224:Expressed Sequence Tags; D054884:Host-Pathogen Interactions; D035683:MicroRNAs / Q000378:metabolism*; D033561:Penaeidae / Q000235:genetics* / Q000821:virology*; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation; D046848:White spot syndrome virus 1 / Q000502:physiology*
chemical_list: D035683:MicroRNAs