title: Characterisation and expression of the paired box protein 7 (Pax7) gene in polymorphic Arctic charr (Salvelinus alpinus).
abstract: Arctic charr (Salvelinus alpinus L.) from Lake Thingvallavatn, Iceland occur as four distinct morphs: large benthivorous (LB), dwarf benthivorous (DB), piscivorous (PI) and planktonivorous (PL). The morphs differ with respect to body size, head morphology, growth rate, and life history. The aim of this study was to investigate the paired box protein 7 (Pax7) gene as a candidate for such polymorphisms due to its importance in cranio-facial, skeletal muscle, and central nervous system development. No variation in coding and intronic sequences was found between morphs. We identified 10 alternate Pax7 isoforms with insertions/deletions: a four-residue (GNRT) deletion, a GEASS insertion truncated by the first serine residue (GEAS), and a thirteen-residue insertion (GQYA/TGPEYVYCGT). The latter insertion with a threonine (T) contains a putative casein kinase II (CK-2) phosphorylation site. Pax7 spatial expression patterns were identical in embryos of DB-, LB-, and PL-morphs, and were similar to those described for zebrafish Pax7c, but a difference in temporal expression for segmentation was observed between DB and LB morphs. At the end of segmentation, novel expression was observed in the mandibular region as two bilateral domains. The potential role of multiple alternative splicing of the Pax7 gene for the generation of different Arctic charr morphs is briefly discussed.
authors.affiliation: Gatty Marine Laboratory, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, Scotland, UK.
authors.forename: Dean
authors.initials: D
authors.lastname: Sibthorpe
authors.forename: Rán
authors.initials: R
authors.lastname: Sturlaugsdóttir
authors.forename: Bjarni K
authors.initials: BK
authors.lastname: Kristjansson
authors.forename: Helgi
authors.initials: H
authors.lastname: Thorarensen
authors.forename: Skúli
authors.initials: S
authors.lastname: Skúlason
authors.forename: Ian A
authors.initials: IA
authors.lastname: Johnston
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D047108:Embryonic Development; D005618:Fresh Water; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D014644:Genetic Variation; D016678:Genome; D007055:Iceland; D007438:Introns; D008969:Molecular Sequence Data; D051763:PAX7 Transcription Factor / Q000737:chemistry* / Q000235:genetics*; D010641:Phenotype; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D019170:Somites / Q000502:physiology; D014337:Trout / Q000033:anatomy & histology / Q000196:embryology / Q000235:genetics*
chemical_list: D051763:PAX7 Transcription Factor; D020033:Protein Isoforms