title: The Invalidation of HspB1 Gene in Mouse Alters the Ultrastructural Phenotype of Muscles.
abstract: Even though abundance of Hsp27 is the highest in skeletal muscle, the relationships between the expression of HspB1 (encoding Hsp27) and muscle characteristics are not fully understood. In this study, we have analysed the effect of Hsp27 inactivation on mouse development and phenotype. We generated a mouse strain devoid of Hsp27 protein by homologous recombination of the HspB1 gene. The HspB1-/- mouse was viable and fertile, showing neither apparent morphological nor anatomical alterations. We detected a gender dimorphism with marked effects in males, a lower body weight (P < 0.05) with no obvious changes in the growth rate, and a lower plasma lipids profile (cholesterol, HDL and triglycerides, 0.001 < P< 0.05). The muscle structure of the animals was examined by optical microscopy and transmission electron microscopy. Not any differences in the characteristics of muscle fibres (contractile and metabolic type, shape, perimeter, cross-sectional area) were detected except a trend for a higher proportion of small fibres. Different myosin heavy chains electrophoretic profiles were observed in the HspB1-/- mouse especially the presence of an additional isoform. Electron microscopy revealed ultrastructural abnormalities in the myofibrillar structure of the HspB1-/- mouse mutant mice (e.g. destructured myofibrils and higher gaps between myofibrils) especially in the m. Soleus. Combined with our previous data, these findings suggest that Hsp27 could directly impact the organization of muscle cytoskeleton at the molecular and ultrastructural levels.
authors: INRA, UMR1213 Herbivores, F-63122, Saint-Genès-Champanelle, France.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France.
authors: Malek
authors: M
authors: Kammoun
authors: INRA, UMR1213 Herbivores, F-63122, Saint-Genès-Champanelle, France.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France.
authors: Brigitte
authors: B
authors: Picard
authors: INRA, UR0370 Qualité des Produits Animaux, F-63122, Saint-Genès-Champanelle, France.
authors: Thierry
authors: T
authors: Astruc
authors: INRA, UMR1213 Herbivores, F-63122, Saint-Genès-Champanelle, France.|Equipe Maquav, INATAA, Université Frères Mentouri Constantine, Constantine, Algeria.
authors: Mohammed
authors: M
authors: Gagaoua
authors: Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS, INRA, École Normale Supérieure de Lyon, F-69364, Lyon, France.
authors: Denise
authors: D
authors: Aubert
authors: INRA, UMR1213 Herbivores, F-63122, Saint-Genès-Champanelle, France.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France.
authors: Muriel
authors: M
authors: Bonnet
authors: INRA, UMR1061 Génétique Moléculaire animale, F-87060, Limoges, France.
authors: Véronique
authors: V
authors: Blanquet
authors: INRA, UMR1213 Herbivores, F-63122, Saint-Genès-Champanelle, France.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France.
authors: Isabelle
authors: I
authors: Cassar-Malek
mesh_terms: D000818:Animals; D005260:Female; D006360:Heat-Shock Proteins / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018613:Microscopy, Confocal / Q000379:methods*; D018832:Molecular Chaperones; D018482:Muscle, Skeletal / Q000473:pathology* / Q000648:ultrastructure*; D009363:Neoplasm Proteins / Q000502:physiology*; D010641:Phenotype
chemical_list: D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins