title: Purpurin is a key molecule for cell differentiation during the early development of zebrafish retina.
abstract: Recently, we cloned purpurin cDNA as an upregulated gene in the axotomized fish retina. The retina-specific protein was secreted from photoreceptors to ganglion cell layer during an early stage of optic nerve regeneration in zebrafish retina. The purpurin worked as a trigger molecule for axonal regrowth in adult injured fish retina. During zebrafish development, purpurin mRNA first appeared in ventral retina at 2 days post-fertilization (dpf) and spread out to the outer nuclear layer at 3 dpf. Here, we investigated the role of purpurin for zebrafish retinal development using morpholino gene knockdown technique. Injection of purpurin morpholino into the 1-2 cell stage of embryos significantly inhibited the transcriptional and translational expression of purpurin at 3 dpf. In the purpurin morphant, the eyeball was significantly smaller and retinal lamination of nuclear and plexiform layers was not formed at 3 dpf. Retinal cells of purpurin morphants were still proliferative and undifferentiated at 3 dpf. The visual function of purpurin morphant estimated by optomotor response was also suppressed at 5 dpf. By contrast, the control morphants with random sequence morpholino showed retinal lamination with distinct layers and differentiated cells at 3 dpf. These results strongly suggest that purpurin is a key molecule for not only optic nerve regeneration in adult but also cell differentiation during early development in embryo.
authors.affiliation: Division of Health Sciences, Graduate School of Medicine, Kanazawa University, Kanazawa, Ishikawa, Japan.
authors.forename: Mikiko
authors.initials: M
authors.lastname: Nagashima
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Mawatari
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tanaka
authors.forename: Tomomi
authors.initials: T
authors.lastname: Higashi
authors.forename: Hikaru
authors.initials: H
authors.lastname: Saito
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Muramoto
authors.forename: Toru
authors.initials: T
authors.lastname: Matsukawa
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Koriyama
authors.forename: Kayo
authors.initials: K
authors.lastname: Sugitani
authors.forename: Satoru
authors.initials: S
authors.lastname: Kato
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D055785:Gene Knockdown Techniques; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D020419:Photoreceptor Cells, Vertebrate / Q000166:cytology / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000378:metabolism; D012177:Retinol-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology; D015027:Zebrafish / Q000196:embryology* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*; D054839:Retinol-Binding Proteins, Plasma
chemical_list: D012333:RNA, Messenger; D012177:Retinol-Binding Proteins; D029961:Zebrafish Proteins; C524558:rbp4l protein, zebrafish; D054839:Retinol-Binding Proteins, Plasma