title: Phenotypic characterization of the Komeda miniature rat Ishikawa, an animal model of dwarfism caused by a mutation in Prkg2.
abstract: The Komeda miniature rat Ishikawa (KMI) is a spontaneous animal model of dwarfism caused by a mutation in Prkg2, which encodes cGMP-dependent protein kinase type II (cGKII). This strain has been maintained as a segregating inbred strain for the mutated allele mri. In this study, we characterized the phenotype of the KMI strain, particularly growth traits, craniofacial measurements, and organ weights. The homozygous mutant (mri/mri) animals were approximately 70% to 80% of the size of normal, heterozygous (mri/+) animals in regard to body length, weight, and naso-occipital length of the calvarium, and the retroperitoneal fat of mri/mri rats was reduced greatly. In addition, among progeny of the (BNxKMI-mri/mri)F1xKMI-mri/mri backcross, animals with the KMI phenotype (mri/mri) were easily distinguished from those showing the wild-type phenotype (mri/+) by using growth traits such as body length and weight. Genetic analysis revealed that all of the backcrossed progeny exhibiting the KMI phenotype were homozygous for the KMI allele in the 1.2-cM region between D14Rat5 and D14Rat80 on chromosome 14, suggesting strongly that mri acts in a completely recessive manner. The KMI strain is the first and only rat model with a confirmed mutation in Prkg2 and is a valuable model for studying dwarfism and longitudinal growth traits in humans and for functional studies of cGKII.
authors.affiliation: Division of Endocrinology and Diabetes, Saitama Medical Center, Saitama Medical University, Saitama, Japan. achi@saitama-med.ac.jp
authors.forename: Atsuko
authors.initials: A
authors.lastname: Tsuchida
authors.forename: Norihide
authors.initials: N
authors.lastname: Yokoi
authors.forename: Misako
authors.initials: M
authors.lastname: Namae
authors.forename: Masanori
authors.initials: M
authors.lastname: Fuse
authors.forename: Taku
authors.initials: T
authors.lastname: Masuyama
authors.forename: Masashi
authors.initials: M
authors.lastname: Sasaki
authors.forename: Shoji
authors.initials: S
authors.lastname: Kawazu
authors.forename: Kajuro
authors.initials: K
authors.lastname: Komeda
mesh_terms: D000818:Animals; D001835:Body Weight / Q000235:genetics; D002874:Chromosome Mapping; D062967:Cyclic GMP-Dependent Protein Kinase Type II; D017869:Cyclic GMP-Dependent Protein Kinases / Q000235:genetics*; D004392:Dwarfism / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D005260:Female; D008297:Male; D009154:Mutation; D009929:Organ Size / Q000235:genetics; D010641:Phenotype; D051381:Rats; D011914:Rats, Inbred BN; D011922:Rats, Mutant Strains
chemical_list: D062967:Cyclic GMP-Dependent Protein Kinase Type II; D017869:Cyclic GMP-Dependent Protein Kinases; C569729:PRKG2 protein, human; C569732:Prkg2 protein, rat