title: Role of PTB-like protein, a neuronal RNA-binding protein, during the differentiation of PC12 cells.
abstract: PTB-like protein (PTBLP) is a new homologue of pyrimidine tract binding protein (PTB), and has been cloned as a possible autoantigen in cancer-associated retinopathy. PTBLP has two functional domains, the nuclear localization signal and the RNA recognition motifs (RRMs). Full-length PTBLP (PTBLP-L) has four RRMs, and its alternative splicing product (PTBLP-S) lacks the third and fourth RRMs. Although PTBLPs are expressed in neuronal tissues, the function of PTBLPs has not been determined. We have studed whether PTBLP plays a role in neuronal differentiation using PC12 cells. During the process of nerve growth factor-induced neuronal differentiation of PC12 cells, PTBLP-L was down-regulated whereas PTBLP-S was up-regulated. Transfection of PTBLP-L into PC12 cells led to the suppression of neuronal differentiation. In PTBLP-S transfected cells, however, this suppression was not evident. When both PTBLP-L and PTBLP-S were co-transfected, the suppressive effect of PTBLP-L decreased. In differentiated cells, PTBLP-S localized in the nucleus and PTBLP-L was found dispersed throughout the cytoplasm and neuronal growth cone. These findings suggest that PTBLP-L acts as a negative regulator of neuronal differentiation and PTBLP-S acts as a competitor of PTBLP-L.
authors.affiliation: Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Ichikawa
authors.forename: Takanobu
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tateiwa
authors.forename: Norimoto
authors.initials: N
authors.lastname: Gotoh
authors.forename: Kouichi
authors.initials: K
authors.lastname: Ohta
authors.forename: Jun
authors.initials: J
authors.lastname: Arai
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D020932:Nerve Growth Factor / Q000494:pharmacology; D016900:Neurofilament Proteins / Q000096:biosynthesis; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D016716:PC12 Cells; D038941:Polypyrimidine Tract-Binding Protein / Q000235:genetics / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000502:physiology; D051381:Rats; D014162:Transfection
chemical_list: D016900:Neurofilament Proteins; D016601:RNA-Binding Proteins; D038941:Polypyrimidine Tract-Binding Protein; D020932:Nerve Growth Factor