title: Disruption of the gaa Gene in Zebrafish Fails to Generate the Phenotype of Classical Pompe Disease.
abstract: The underlying pathogenic lesions of glycogen storage disease type II (GSD II) and the diversity of this disease among different species are still under exploration. Thus, we created an acid alpha-glucosidase (gaa) gene-mutated zebrafish model of GSD II and examined the sequential pathogenic changes. gaa mRNA and protein expression, enzymatic activity, and lysosomal glycogen accumulation were assessed, and the phenotypic changes were compared between wild-type (WT) and gaa-mutated zebrafish. The presence of a Δ13 frameshift mutation in the gaa gene was confirmed at both the DNA and transcribed mRNA levels by Sanger sequencing. The relative amount of gaa mRNA was decreased before 2 days postfertilization (dpf), after which it unexpectedly increased in the mutant compared with the WT zebrafish. Consistent with the mRNA expression, the Gaa enzymatic activity in the mutant was downregulated before 3 dpf, while the Gaa protein level was slightly decreased at 4 dpf and was maintained at a consistent level in the adult gaa mutant muscle tissue. However, more than half of the adult mutant zebrafish exhibited excessive glycogen accumulation in the liver and muscles, along with the presence of autophagosomes, as determined by transmission electron microscopy. Thus, we have successfully generated a frameshift mutation in the gaa gene in zebrafish. The unique gaa gene expression changes and mild GSD II features during the adult stage strongly indicate the existence of species-specific differences, as well as an underlying compensatory network, which may warrant further examination.
authors.affiliation: 1 Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.affiliation: 2 Institute of Pediatrics, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: 1 Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Chengjun
authors.initials: C
authors.lastname: Sun
authors.affiliation: 3 Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University , Shanghai, China .
authors.forename: Shaoyang
authors.initials: S
authors.lastname: Sun
authors.affiliation: 4 Translational Medical Center for Development and Disease, Shanghai Key Laboratory of Birth Defect, Institute of Pediatrics, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.affiliation: 2 Institute of Pediatrics, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Yuxiao
authors.initials: Y
authors.lastname: Yao
authors.affiliation: 2 Institute of Pediatrics, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Fei
authors.initials: F
authors.lastname: Fei
authors.affiliation: 5 Department of Chronic Disease Epidemiology, Yale School of Public Health, School of Medicine, Yale Cancer Center, Yale University , New Haven, Connecticut.
authors.forename: Lingeng
authors.initials: L
authors.lastname: Lu
authors.affiliation: 1 Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Chang
authors.affiliation: 1 Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Wenting
authors.initials: W
authors.lastname: Zhang
authors.affiliation: 3 Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University , Shanghai, China .
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.affiliation: 1 Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University , Shanghai, China .
authors.forename: Feihong
authors.initials: F
authors.lastname: Luo
mesh_terms: D000818:Animals; D001483:Base Sequence; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006003:Glycogen / Q000378:metabolism; D006009:Glycogen Storage Disease Type II / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D000520:alpha-Glucosidases / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D006003:Glycogen; D000520:alpha-Glucosidases
keywords: Pompe disease; enzymatic activity; gaa; mutant; phenotype; zebrafish