Research in the laboratory of Brian D. Perkins, Ph.D., seeks to develop zebrafish models that mimic photoreceptor degeneration in childhood diseases like Leber Congenital Amaurosis.
Our long-term goal is to understand the mechanisms regulating cilia assembly and why defects in these processes cause photoreceptor degeneration. Vertebrate photoreceptor outer segments form from the connecting cilium, which is anchored by a basal body at the apical inner segment. The connecting cilium connects the inner segment to the outer segment and is the gateway for proteins destined for the outer segment. Mutations in cilia or basal body proteins disrupt protein trafficking and result in multisyndromic diseases termed ciliopathies, which often manifest with retinal degeneration. Cilia formation and function depend on the proper placement and anchoring of the basal body at the apical surface, but the mechanisms controlling basal body location remain poorly understood – particularly in photoreceptors. Furthermore, how altered positioning of basal bodies influences pathology is not fully understood. Little is known about the mechanisms controlling basal body docking and other early steps of cilia formation. By understanding the mechanisms governing ciliary positioning, it will be possible to understand how mutations in individual genes contribute to blindness. We utilize the zebrafish as an experimental system for several reasons: (1) zebrafish photoreceptor anatomy is well-characterized; (2) zebrafish photoreceptors provide an accessible, stereotyped population to analyze genetic defects; (3) techniques exist to manipulate gene expression, rapidly generate transgenic lines, and create genetic mosaic embryos; and (4) we have a wide number of zebrafish transgenic and mutant lines to investigate processes required for cilia. Achieving a better molecular understanding of basal body localization in photoreceptors could lead to potential therapies for human retinal damage and disease.
Research & Innovations
1.) Zebrafish models of childhood blindness
1. Genetic and functional studies of cell polarity during photoreceptor cilia formation
Personnel: Ping Song, Joe Fogerty,
(a) The goal of this project is to determine the role of Planar Cell Polarity (PCP) signaling in ciliary positioning and photoreceptor survival in zebrafish. In many tissues, cilia function relies on the asymmetric positioning and/or tilting of the cliium to one side of the cell. The PCP signaling pathway regulates basal body docking on the apical surface and cilia positioning. Defects in PCP signaling contribute to ciliopathies and ciliary proteins directly bind with key PCP proteins. Our preliminary data reveals a highly arranged pattern of basal bodies in zebrafish photoreceptors. We hypothesize that PCP signaling functions to position photoreceptor cilia. We hypothesize that disrupting PCP signaling will disrupt this pattern and be deleterious to photoreceptors.
(b) The goal is to determine the functional interactions between PCP signaling and arl13b on cilia function in zebrafish photoreceptors. Mutations arl13b result in Joubert Syndrome, which presents with variable retinal dystrophy. Arl13b localizes to cilia and mutations disrupt cilia structure. Our preliminary data indicates that Arl13b and PCP components can genetically interact to result in retinal degeneration. We will use light and electron microscopy to examine photoreceptor ultrastructure arl13b mutants. We will use genetic mosaic analysis to examine the long-term fate of mutant photoreceptors in wild type zebrafish. To determine relationship between Arl13b and PCP signaling, both genetic and physical interactions will be tested. Finally, the requirement for
GTPase activity and ciliary localization of Arl13b will be tested using mutant alleles at key amino acid residues.
In other words ...
The goal of my laboratory is to understand what causes the rods and cones of the retina die in genetic forms of blindness. We use zebrafish as a model to study inherited eye disorders in humans. Specifically, we are investigating zebrafish with mutations in the gene cep290, as mutations in this gene are a major cause of Leber Congenital Amaurosis (LCA), an inherited form of childhood blindness.
Joseph Fogerty Ph.D.
Robert Gaivin B.S.
Lead Research Technologist
Emma M. Lessieur MD
Mol Med Graduate Student
1 Ramsey, M. and Perkins, B. D. (2013) Basal bodies exhibit polarized positioning in zebrafish cone photoreceptors. Journal of Comparative Neurology. 521(8):1803-16. PMID:23171982
2 Wasfy, M. M., Matsui, J. I, Miller, J., Dowling, J. E., and Perkins, B. D. (2014) myosin 7aa-/- mutant zebrafish show photoreceptor degeneration and reduced electroretinographic responses. Experimental Eye Research. 122:65-76. PMCID: PMC4034177
3 Krock, B. L., and Perkins, B. D. (2014) The Par-PrkC polarity complex is required for ciliogenesis in vertebrate photoreceptors. PLoS One 9(8) e104661 PMID: 251447.
4 DiCicco RM*, Bell BA*, Kaul C, Hollyfield JG, Anand-Apte B, Perkins BD, Tao YK, and Yuan A. (2014) Retinal Regeneration Following OCT-guided Laser Injury in Zebrafish. Invest Ophthalmol Vis Sci. Sep 9;55(10):6281-8. PMID: 25205862.
5 Babino, D., Perkins, B. D., Kindermann, A., Oberhauser, V., and von Lintig, J. (2015) The Role of 11-cis-Retinyl Esters in Vertebrate Cone Vision. FASEB J. 2015. 29(1):216-26. PMID: 25326538
6 Fogerty, J., Denton, K, and Perkins, B. D. (2016) Mutations in the Dynein1 Complex are Permissible for Basal Body Migration in Photoreceptors but Alter Rab6 Localization. Adv. Exp. Med. Biol. 854:209-15. PMID: 26427413
7 Daniele, L. L., Emran, F., Lobo, G. P., Gaivin, R. J., and Perkins, B. D. (2016) Mutation of wrb, a Component of the Guided Entry of Tail-Anchored Protein (GET) Pathway, Disrupts Photoreceptor Synapse Structure and Function. Investigative Ophthalmology and Visual Sciences 57(7):2942-54. PMID: 27273592
8 Song, P., Dudinsky, L., Fogerty, J., Gaivin, R. J., and Perkins, B. D. (2016) Arl13b Interacts with Vangl2 to Regulate Cilia and Photoreceptor Outer Segment Length in Zebrafish. Investigative Ophthalmology and Visual Sciences. 2016 Aug 1;57(10):4517-26. PubMed PMID: 27571019; PubMed Central PMCID: PMC5015978.
9 Bell, B. A., Yuan, A., Dicicco, R. M., Fogerty, J., Lessieur, E. M., and Perkins B. D. (2016) The Adult Zebrafish Retina: In vivo Optical Sectioning with Confocal Scanning Laser Ophthalmoscopy and Spectral-Domain Optical Coherence Tomography. Experimental Eye Research. Dec. 153:65-78 PubMed PMID: 27720860 PubMed Central PMCID: PMC5120996
10 Lessieur, E. M., Fogerty, J., Gaivin, R. J., Song P., and Perkins, B. D. (2017) The ciliopathy gene ahi1 is required for zebrafish cone photoreceptor outer segment morphogenesis. Investigative Ophthalmology and Visual Sciences. Jan 1;58(1):448-460. PubMed PMID: 28118669; PubMed Central PMCID: PMC5270624.