title: Isolation and characterization of brain Y-box protein: developmentally regulated expression, polyribosomal association and dendritic localization.
abstract: Y-box proteins are DNA- and RNA-binding proteins and control specific gene expression at both transcriptional and translational levels. Particularly in germ cells, it has been reported that Y-box proteins bind to paternal or maternal mRNAs to form mRNPs, mask them from translation and control cell maturation. In this study, we cloned cDNA for a Y-box protein from rat brain. A deduced amino acid sequence of the protein was very similar to that of several other Y-box proteins, and we termed the protein rBYB1 (rat brain Y-box protein 1). rBYB1 was found to be considerably expressed in the cytoplasm of pre- and early postnatal brains, and then decreased to adult levels with brain development. Further, we found rBYB1 to be distributed in both polyribosomal and nonpolyribosomal (mRNP) fractions on a sucrose density gradient, and to be associated with polyribosomes via RNA in the higher-density fractions. Moreover, rBYB1 was localized in dendrites of the primary hippocampal neurons. We compared these sucrose gradient and intracellular rBYB1 localization results with those for fragile X mental retardation protein (FMRP), which is known to be an mRNA-binding and polyribosome-associating translational regulator distributed in neuronal dendrites. Our results suggest that in the brain of prenatal and newborn animals, rBYB1 may function in storage and/or translational regulation of mRNAs involved in the rapid progress of the postnatal brain, and in mature neurons, it may also participate in the control of protein synthesis in dendrites.
authors.affiliation: Department of Biochemistry, College of Pharmacy, Nihon University, Narashinodai, Funabashi, Chiba 274-8555, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Funakoshi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Ohashi
authors.forename: Taka Aki
authors.initials: TA
authors.lastname: Sato
authors.forename: Kaijiro
authors.initials: K
authors.lastname: Anzai
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence / Q000235:genetics; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D003712:Dendrites / Q000378:metabolism; D005333:Fetus; D051860:Fragile X Messenger Ribonucleoprotein 1; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D011132:Polyribosomes / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification*; D051381:Rats
chemical_list: D018076:DNA, Complementary; D051860:Fragile X Messenger Ribonucleoprotein 1; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C497684:Fmr1 protein, mouse; C497685:Fmr1 protein, rat; C481842:brain Y-box protein 1, rat