title: Isx participates in the maintenance of vitamin A metabolism by regulation of beta-carotene 15,15'-monooxygenase (Bcmo1) expression.
abstract: Isx (intestine specific homeobox) is an intestine-specific transcription factor. To elucidate its physiological function, we generated Isx-deficient mice by knocking in the beta-galactosidase gene (LacZ) in the Isx locus (IsxLacZ/LacZ mice). LacZ staining of heterozygous (IsxLacZ/+) mice revealed that Isx was expressed abundantly in intestinal epithelial cells from duodenum to proximal colon. Quantitative mRNA expression profiling of duodenum and jejunum showed that beta-carotene 15,15'-monooxygenase (EC1.14.99.36 Bcmo1) and the class B type I scavenger receptor, which are involved in vitamin A synthesis and carotenoid uptake, respectively, were drastically increased in IsxLacZ/LacZ mice. Although mild vitamin A deficiency decreased Isx expression in duodenum of wild-type (Isx+/+) mice, severe vitamin A deficiency decreased Isx mRNA expression in both duodenum and jejunum of Isx+/+ mice. On the other hand, vitamin A deficiency increased Bcmo1 expression in both duodenum and jejunum of Isx+/+ mice. However, Bcmo1 expression was not increased in duodenum of IsxLacZ/LacZ mice by mild vitamin A deficiency. These data suggest that Isx participates in the maintenance of vitamin A metabolism by regulating Bcmo1 expression in the intestine.
authors: Division of Cellular and Molecular Medicine, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
authors: Yusuke
authors: Y
authors: Seino
authors: Takashi
authors: T
authors: Miki
authors: Hiroshi
authors: H
authors: Kiyonari
authors: Takaya
authors: T
authors: Abe
authors: Wakako
authors: W
authors: Fujimoto
authors: Keita
authors: K
authors: Kimura
authors: Ayako
authors: A
authors: Takeuchi
authors: Yoshihisa
authors: Y
authors: Takahashi
authors: Yutaka
authors: Y
authors: Oiso
authors: Toshihiko
authors: T
authors: Iwanaga
authors: Susumu
authors: S
authors: Seino
mesh_terms: D000818:Animals; D004386:Duodenum / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007583:Jejunum / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D051122:Scavenger Receptors, Class B / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014801:Vitamin A / Q000235:genetics / Q000378:metabolism*; D014802:Vitamin A Deficiency / Q000235:genetics / Q000378:metabolism; D019207:beta Carotene / Q000378:metabolism*; D050559:beta-Carotene 15,15'-Monooxygenase / Q000096:biosynthesis* / Q000235:genetics
chemical_list: C527930:Isx protein, mouse; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D014157:Transcription Factors; D019207:beta Carotene; D014801:Vitamin A; C493359:Bco1 protein, mouse; D050559:beta-Carotene 15,15'-Monooxygenase