title: Transcriptomic and iTRAQ proteomic approaches reveal novel short-term hyperosmotic stress responsive proteins in the gill of the Japanese eel (Anguilla japonica).
abstract: Osmoregulation is critical for the survival of fishes that migrate between freshwater (FW) and seawater (SW). The eel, as a catadromous fish, has been studied for decades to reveal the mechanisms of osmoregulation. These studies, however, have been limited by the lack of a genomic database to decipher the mechanism of osmoregulation at a molecular level. In this study, using high-throughput transcriptomic and proteomic technologies, we have provided the first genome-wide study to identify hyperosmotic responsive proteins in the gills of the Japanese eel. Deep sequencing using the 454 platform produced over 660,000 reads with a mean length of 385 bp. For the proteomic study, we collected gill samples from three different treatment groups of fish that had fully adapted to FW/SW or were transferred from FW to SW for 6h. The respective group of gill proteins were extracted and labeled using an isobaric tag for relative and absolute quantitation (iTRAQ) using LTQ-Orbitrap, a high resolution mass spectrometer. Among the 1519 proteins identified from the gill samples, 96 proteins were differentially expressed between FW and SW adapted fish. Nineteen hyperosmotic responsive proteins were detected (10 up-regulated and 9 down-regulated proteins) after 6h post FW to SW transfer.
  
  
  CONCLUSIONS
  The study has provided the most comprehensive, targeted investigation of eel gill proteins to date, and shown the powerfulness of combining transcriptomic and proteomic approaches to provide molecular insights of osmoregulation mechanisms in a non-model organism, eel.
authors.affiliation: Department of Biology, Hong Kong Baptist University, Hong Kong. kftse@hkbu.edu.hk
authors.forename: William Ka Fai
authors.initials: WK
authors.lastname: Tse
authors.forename: Jin
authors.initials: J
authors.lastname: Sun
authors.forename: Huoming
authors.initials: H
authors.lastname: Zhang
authors.forename: Alice Yu Sheung
authors.initials: AY
authors.lastname: Law
authors.forename: Bonnie Ho Yee
authors.initials: BH
authors.lastname: Yeung
authors.forename: Sheung Ching
authors.initials: SC
authors.lastname: Chow
authors.forename: Jian-Wen
authors.initials: JW
authors.lastname: Qiu
authors.forename: Chris Kong Chu
authors.initials: CK
authors.lastname: Wong
mesh_terms: D000818:Animals; D004524:Eels / Q000378:metabolism*; D029941:Fish Proteins / Q000096:biosynthesis*; D005618:Fresh Water; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005880:Gills / Q000378:metabolism*; D009997:Osmotic Pressure / Q000502:physiology*; D040901:Proteomics; D012623:Seawater
chemical_list: D029941:Fish Proteins
keywords: 2DE; CID; Eel; FW; GO; Gene Ontology; Gill; HCD; Hyperosmotic stress; KEGG; Kyoto Encyclopedia of Genes And Genomes; MS; PPI; SRA; SW; Transcriptome; collision-induced dissociation; freshwater; high-energy collision-induced dissociation; iTRAQ; isobaric tag for relative and absolute quantitation; mass spectrometry; protein–protein interaction; seawater; short read archive; two-dimensional electrophoresis