Developmental pattern of the neuronal intermediate filament inaa in the zebrafish retina

• Published in: Journal of comparative neurology (1911) 2016-12, Vol.524 (18), p.3810-3826
• Main Authors: Liao, Meng-Lin, Peng, Wei-Hau, Kan, Daphne, Chien, Chung-Liang
• Format: Article
• Language: English
• Subjects: Animals; Blotting, Western; Cell Line, Tumor; Danio rerio; development; Fluorescent Antibody Technique; Gene Expression Regulation, Developmental; Intermediate Filament Proteins - chemistry; Intermediate Filament Proteins - genetics; Intermediate Filament Proteins - metabolism; Mice; Microscopy, Confocal; Microscopy, Electron, Transmission; neurofilament; NIH 3T3 Cells; Photomicrography; Phylogeny; retina; Retina - cytology; Retina - growth & development; Retina - metabolism; Sequence Homology, Amino Acid; zebrafish (RRID:ZIRC_ZL1); Zebrafish - anatomy & histology; Zebrafish - genetics; Zebrafish - growth & development; Zebrafish - metabolism; Zebrafish Proteins - chemistry; Zebrafish Proteins - genetics; Zebrafish Proteins - metabolism; α-internexin
• ISSN: 0021-9967; 1096-9861
• DOI: 10.1002/cne.24033

α‐Internexin is a member of the neuronal intermediate filament (nIF) protein family, which also includes peripherin and neurofilament (NF) triplet proteins. Previous studies found that expression of α‐internexin precedes that of the NF triplet proteins in mammals and suggested that α‐internexin plays a key role in the neuronal cytoskeleton network during development. In this study, we aimed to analyze the expression patterns and function of internexin neuronal intermediate filament protein‐alpha a (inaa), the encoding gene of which is a homolog of the mammalian α‐internexin, during retinal development in zebrafish. Via in vitro and in vivo studies, we demonstrated that zebrafish inaa is an α‐internexin homolog that shares characteristics with nIFs. An immunohistochemical analysis of zebrafish revealed that inaa was distributed dynamically in the developing retina. It was widely localized in retinal neuroepithelial cells at 1 day postfertilization (dpf), and was mainly found in the ganglion cell layer (GCL) and inner part of the inner nuclear layer (INL) from 3–9 dpf; after 14 dpf, it was restricted to the outer nuclear layer (ONL). Moreover, we demonstrated for the first time that inaa acted distinctively from the cytoskeletal scaffold of zebrafish cone photoreceptors during development. In conclusion, we demonstrated the morphological features of a novel nIF, inaa, and illustrated its developmental expression pattern in the zebrafish retina. J. Comp. Neurol. 524:3810–3826, 2016. © 2016 Wiley Periodicals, Inc. In this study, we describe the morphological features of zebrafish inaa and show that the developmental expression pattern of the inaa protein is dynamic in the developing retina. This figure shows that inaa acted distinctively as a scaffold of adult zebrafish cone photoreceptors. Scale bar = 25 μm.