title: De novo assembly and transcriptome characterization: novel insights into the natural resistance mechanisms of Microtus fortis against Schistosoma japonicum.
abstract: BACKGROUND
  Microtus fortis is a non-permissive host of Schistosoma japonicum. It has natural resistance against schistosomes, although the precise resistance mechanisms remain unclear. The paucity of genetic information for M. fortis limits the use of available immunological methods. Thus, studies based on high-throughput sequencing technologies are required to obtain information about resistance mechanisms against S. japonicum.
  
  
  RESULTS
  Using Illumina single-end technology, a de novo assembly of the M. fortis transcriptome produced 67,751 unigenes with an average length of 868 nucleotides. Comparisons were made between M. fortis before and after infection with S. japonicum using RNA-seq quantification analysis. The highest number of differentially expressed genes (DEGs) occurred two weeks after infection, and the highest number of down-regulated DEGs occurred three weeks after infection. Simultaneously, the strongest pathological changes in the liver were observed at week two. Gene ontology terms and pathways related to the DEGs revealed that up-regulated transcripts were involved in metabolism, immunity and inflammatory responses. Quantitative real-time PCR analysis showed that patterns of gene expression were consistent with RNA-seq results.
  
  
  CONCLUSIONS
  After infection with S. japonicum, a defensive reaction in M. fortis commenced rapidly, increasing dramatically in the second week, and gradually decreasing three weeks after infection. The obtained M. fortis transcriptome and DEGs profile data demonstrated that natural and adaptive immune responses, play an important role in M. fortis immunity to S. japonicum. These findings provide a better understanding of the natural resistance mechanisms of M. fortis against schistosomes.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Hu
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Xu
authors.forename: Weiyuan
authors.initials: W
authors.lastname: Lu
authors.forename: Zhongying
authors.initials: Z
authors.lastname: Yuan
authors.forename: Hong
authors.initials: H
authors.lastname: Quan
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Shen
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Key Laboratory of Parasite and Vector Biology, MOH, Shanghai 200025, China. caojp@yahoo.com.
authors.forename: Jianping
authors.initials: J
authors.lastname: Cao
mesh_terms: D000820:Animal Diseases / Q000235:genetics* / Q000276:immunology / Q000469:parasitology; D000818:Animals; D003411:Arvicolinae / Q000235:genetics* / Q000276:immunology / Q000469:parasitology; D016000:Cluster Analysis; D019295:Computational Biology; D060467:Disease Resistance / Q000235:genetics* / Q000276:immunology; D020869:Gene Expression Profiling; D007113:Immunity, Innate / Q000235:genetics*; D008099:Liver / Q000378:metabolism / Q000469:parasitology / Q000473:pathology; D058977:Molecular Sequence Annotation; D015203:Reproducibility of Results; D012549:Schistosoma japonicum / Q000276:immunology*; D015398:Signal Transduction; D059467:Transcriptome