title: Selenoprotein N: an endoplasmic reticulum glycoprotein with an early developmental expression pattern.
abstract: Rigid spine muscular dystrophy and the classical form of multiminicore disease are caused by mutations in SEPN1 gene, leading to a new clinical entity referred to as SEPN1-related myopathy. SEPN1 codes for selenoprotein N, a new member of the selenoprotein family, the function of which is still unknown. In a previous study, two isoforms were deduced from SEPN1 transcript analyses. Using polyclonal antibodies directed against SEPN1 and cDNA constructs encoding for the two isoforms, we show that the main SEPN1 gene product corresponds to a 70 kDa protein, containing a single selenocysteine residue. Subcellular fractionation experiments and endoglycosidase H sensitivity indicate that SEPN1 is a glycoprotein-localized within the endoplasmic reticulum. Immunofluorescence analyses confirm this subcellular localization and green fluorescent protein fusion experiments demonstrate the presence of an endoplasmic reticulum-addressing and -retention signal within the N-terminus. SEPN1 is present at a high level in several human fetal tissues and at a lower level in adult ones, including skeletal muscle. Its high expression in cultured myoblasts is also down-regulated in differentiating myotubes, suggesting a role for SEPN1 in early development and in cell proliferation or regeneration.
authors.affiliation: INSERM U582, Institut de Myologie, GH Pitié-Salpêtrière, Paris, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Petit
authors.forename: Alain
authors.initials: A
authors.lastname: Lescure
authors.forename: Mathieu
authors.initials: M
authors.lastname: Rederstorff
authors.forename: Alain
authors.initials: A
authors.lastname: Krol
authors.forename: Behzad
authors.initials: B
authors.lastname: Moghadaszadeh
authors.forename: Ulla M
authors.initials: UM
authors.lastname: Wewer
authors.forename: Pascale
authors.initials: P
authors.lastname: Guicheney
mesh_terms: D002455:Cell Division / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005333:Fetus / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D009124:Muscle Proteins / Q000378:metabolism*; D021382:Protein Sorting Signals; D051140:Selenoproteins
chemical_list: D009124:Muscle Proteins; D021382:Protein Sorting Signals; C435489:SELENON protein, human; D051140:Selenoproteins