title: iTRAQ-based quantitative proteomic analysis reveals acute hypo-osmotic responsive proteins in the gills of the Japanese eel (Anguilla japonica).
abstract: Osmoregulation in fish has been a classical research topic for several decades. Salmon and eels are the widely used model animals because of their wide distribution in different geographical locations and spawning migration between fresh- and salt-water habitats. Numerous fish osmoregulatory hormones and ion transporters were identified for their essential roles in acclimation and adaptation to waters of different salinities. Because of the lack of a genomic database, the scope of most studies, however, is very limited. Recently, our group reported the first high-throughput transcriptomic and proteomic studies to identify hyperosmotic-responsive genes/proteins in gills of Japanese eels. In this study, we aimed to decipher changes in hypo-osmotic-responsive proteins in fish acclimating from seawater (SW) to freshwater (FW) conditions. We collected gill samples from SW-adapted and SW-to-FW-acclimating fish. The respective gill proteins were extracted and labeled using isobaric tags for relative and absolute quantitation (iTRAQ) and analyzed using a high-resolution mass spectrometer. In the short-term transfer from SW to FW, 51 hypo-responsive proteins were detected, and 24 unique hypo-osmotic-responsive proteins were identified (15 up-regulated and nine down-regulated proteins). Our data support the use of an omics approach to facilitate the application of functional genomics in non-model organisms.
  
  
  CONCLUSIONS
  By combining transcriptomic and proteomic approaches, the study has provided the most comprehensive, targeted investigation of eel gill hypo-osmotic responsive proteins that provides molecular insights of osmoregulation mechanisms in a non-model organism, eel. This article is part of a Special Issue entitled: Proteomics of non-model organisms.
authors: Department of Biology, Hong Kong Baptist University, Hong Kong. Electronic address: kftse@hkbu.edu.hk.
authors: William Ka Fai
authors: WK
authors: Tse
authors: Department of Biology, Hong Kong Baptist University, Hong Kong.
authors: Jin
authors: J
authors: Sun
authors: Department of Biology, Hong Kong Baptist University, Hong Kong.
authors: Huoming
authors: H
authors: Zhang
authors: School of Biological Science, The University of Hong Kong, Hong Kong.
authors: Keng Po
authors: KP
authors: Lai
authors: Department of Biology, Hong Kong Baptist University, Hong Kong.
authors: Jie
authors: J
authors: Gu
authors: Department of Biology, Hong Kong Baptist University, Hong Kong.
authors: Jian-Wen
authors: JW
authors: Qiu
authors: Department of Biology, Hong Kong Baptist University, Hong Kong; Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Hong Kong. Electronic address: ckcwong@hkbu.edu.hk.
authors: Chris Kong Chu
authors: CK
authors: Wong
mesh_terms: D000818:Animals; D004524:Eels / Q000235:genetics / Q000378:metabolism*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D005618:Fresh Water; D005880:Gills / Q000378:metabolism*; D009997:Osmotic Pressure / Q000502:physiology*; D040901:Proteomics / Q000379:methods*; D012623:Seawater
chemical_list: D029941:Fish Proteins
keywords: Eel; Gill; Hypo-osmotic stress; Transcriptome; iTRAQ