title: Skeletal muscle plasticity induced by seasonal acclimatization involves IGF1 signaling: implications in ribosomal biogenesis and protein synthesis.
abstract: One of the most fundamental biological processes in living organisms that are affected by environmental fluctuations is growth. In fish, skeletal muscle accounts for the largest proportion of body mass, and the growth of this tissue is mainly controlled by the insulin-like growth factor (IGF) system. By using the carp (Cyprinus carpio), a fish that inhabits extreme conditions during winter and summer, we assessed the skeletal muscle plasticity induced by seasonal acclimatization and the relation of IGF signaling with protein synthesis and ribosomal biogenesis. The expression of igf1 in muscle decreased during winter in comparison with summer, whereas the expression for both paralogues of igf2 did not change significantly between seasons. The expression of igf1 receptor a (igf1ra), but not of igf1rb, was down-regulated in muscle during the winter as compared to the summer. A decrease in protein contents and protein phosphorylation for IGF signaling molecules in muscle was observed in winter-acclimatized carp. This was related with a decreased expression in muscle for markers of myogenesis (myoblast determination factor (myod), myogenic factor 5 (myf5), and myogenin (myog)); protein synthesis (myosin heavy chain (mhc) and myosin light chain (mlc3 and mlc1b)); and ribosomal biogenesis (pre-rRNA and ribosomal proteins). IGF signaling, and key markers of ribosomal biogenesis, protein synthesis, and myogenesis were affected by seasonal acclimatization, with differential regulation in gene expression and signaling pathway activation observed in muscle between both seasons. This suggests that these molecules are responsible for the muscle plasticity induced by seasonal acclimatization in carp.
authors.affiliation: Laboratorio de Biotecnología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Av. Republica 217, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción, Chile. Electronic address: edua.fuentes@uandresbello.edu.
authors.forename: Eduardo N
authors.initials: EN
authors.lastname: Fuentes
authors.affiliation: Laboratorio de Biotecnología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Av. Republica 217, Santiago, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Zuloaga
authors.affiliation: Laboratorio de Biotecnología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Av. Republica 217, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción, Chile.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Valdes
authors.affiliation: Laboratorio de Biotecnología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Av. Republica 217, Santiago, Chile; Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción, Chile.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Molina
authors.affiliation: Interdisciplinary Center for Aquaculture Research (INCAR), Víctor Lamas 1290, PO Box 160-C, Concepción, Chile; Laboratorio de Biología Celular y Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Quillota 980, Viña del Mar, Chile. Electronic address: marcoalvarez@unab.cl.
authors.forename: Marco
authors.initials: M
authors.lastname: Alvarez
mesh_terms: D000064:Acclimatization; D000818:Animals; D015415:Biomarkers; D002347:Carps / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008024:Ligands; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000254:growth & development / Q000378:metabolism*; D010766:Phosphorylation; D014176:Protein Biosynthesis; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism*; D012621:Seasons; D015398:Signal Transduction
chemical_list: D015415:Biomarkers; D008024:Ligands; D012269:Ribosomal Proteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1
keywords: Acclimatization; Fish; IGF signaling; Protein synthesis; Ribosomal biogenesis; Skeletal muscle