title: Characterization of the carotenoid-binding protein of the Y-gene dominant mutants of Bombyx mori.
abstract: Carotenoids play important and diverse roles in insects. Recently, we purified and partially characterized a carotenoid-binding protein (CBP) from the wild type of Bombyx mori. In this report, we utilized immunoblotting, ELISA and immunocytochemistry to further characterize and localize the expression of CBP in the larval midgut and silk gland obtained from the wild type and four naturally occurring mutants linked to carotenoids transport. CBP was expressed throughout the 5th stadium, with highest expressions on days 4-5 in the silk gland and days 3-5 in the midgut. Immunoblotting analyses demonstrated the presence of CBP along the middle part of the midgut. Microscopic immunocytochemistry demonstrated that the 33 kDa CBP was uniformly expressed along the brush border of columnar cells in the epithelium of the midgut typifying its function in aiding absorption of dietary carotenoids. Similarly, CBP was highly expressed along the distal membrane of the middle part of the silk gland demonstrating its function in uptake of carotenoids from lipophorin. When the middle silk glands and midguts of the four mutants were incubated with rabbit anti-CBP antibody, only proteins of the Y-gene dominant mutants cross reacted with the antibody further accentuating the hypothesis that the CBP is a Y-gene dependent protein.
authors.affiliation: Radiological Protection, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Tsuchida
authors.forename: Zeina E
authors.initials: ZE
authors.lastname: Jouni
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gardetto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tabunoki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Azuma
authors.forename: Hiromu
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Naoko
authors.initials: N
authors.lastname: Takada
authors.forename: Hideaki
authors.initials: H
authors.lastname: Maekawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Banno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujii
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Iwano
authors.forename: Michael A
authors.initials: MA
authors.lastname: Wells
mesh_terms: D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D002338:Carotenoids / Q000378:metabolism*; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D005088:Exocrine Glands / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000648:ultrastructure; D015870:Gene Expression; D017344:Genes, Insect; D015151:Immunoblotting; D007150:Immunohistochemistry; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism / Q000648:ultrastructure; D009154:Mutation
chemical_list: D002352:Carrier Proteins; D019476:Insect Proteins; D002338:Carotenoids