title: Rescue of retinal morphology and function in a humanized mouse at the mouse retinol-binding protein locus.
abstract: Retinol-binding protein RBP4 is the specific carrier for retinol in the blood. We previously produced a Rbp4-deficient (Rbp4-/-) mouse that showed electroretinogram (ERG) abnormalities, accompanied by histological and electron-microscopic changes such as fewer synapses in the inner plexiform layer in the central retina. To address whether human RBP4 gene expression can rescue the phenotypes observed in Rbp4-/-mice, we produced a humanized (Rbp4hRBP4orf/ hRBP4orf) mouse with a human RBP4 open reading frame in the mouse Rbp4 locus using a Cre-mutant lox recombination system. In Rbp4hRBP4orf/hRBP4orfmice, the tissue-specific expression pattern of hRBP4orf was roughly the same as that of mouse Rbp4. ERG and morphological abnormalities observed in Rbp4-/-mice were rescued in Rbp4hRBP4orf/hRBP4orfmice as early as 7 weeks of age. The temporal expression pattern of hRBP4orf in the liver of Rbp4hRBP4orf/hRBP4orfmice was similar to that of mouse Rbp4 in Rbp4+/+mice. In contrast, hRBP4orf expression levels in eyes were significantly lower at 6 and 12 weeks of age compared with mouse Rbp4 but were restored to the control levels at 24 weeks. The serum hRBP4 levels in Rbp4hRBP4orf/hRBP4orfmice were approximately 30% of those in Rbp4+/+at all ages examined. In accordance with this finding, the plasma retinol levels remained low in Rbp4hRBP4orf/hRBP4orfmice. Retinol accumulation in the liver occurred in control and Rbp4hRBP4orf/hRBP4orfmice but was higher in Rbp4hRBP4orf/hRBP4orfmice at 30 weeks of age. Mouse transthyretin expression was not altered in Rbp4-/-or Rbp4hRBP4orf/hRBP4orfmice. Taken together, 30% of the serum RBP4 level was sufficient to correct the abnormal phenotypes observed in Rbp4-/-mice.
authors.affiliation: Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang, China.|Yamamura Project Laboratory, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Kumamoto, Japan.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Technology and Development Team for Mouse Phenotype Analysis, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang, China.
authors.forename: Jingling
authors.initials: J
authors.lastname: Shen
authors.affiliation: Technology and Development Team for Mouse Phenotype Analysis, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan.
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Wakana
authors.affiliation: Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Kumamoto, Japan.
authors.forename: Kimi
authors.initials: K
authors.lastname: Araki
authors.affiliation: Yamamura Project Laboratory, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Kumamoto, Japan.
authors.forename: Ken-Ichi
authors.initials: KI
authors.lastname: Yamamura
authors.affiliation: Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.affiliation: Department of Histology and Embryology, Harbin Medical University, Harbin, Heilongjiang, China.|Yamamura Project Laboratory, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Kumamoto, Japan.
authors.forename: Zhenghua
authors.initials: Z
authors.lastname: Li
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D004596:Electroretinography; D005123:Eye / Q000378:metabolism / Q000648:ultrastructure; D020869:Gene Expression Profiling / Q000379:methods*; D006801:Humans; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D009928:Organ Specificity / Q000235:genetics*; D012160:Retina / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D054839:Retinol-Binding Proteins, Plasma / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000378:metabolism; D014801:Vitamin A / Q000097:blood
chemical_list: C101326:RBP4 protein, human; C502487:Rbp4 protein, mouse; D054839:Retinol-Binding Proteins, Plasma; D014801:Vitamin A