Rod photoreceptor number is regulated by the locus lots-of-rods-junior (ljr) in the zebrafish retina

Abstract

Event Abstract Back to Event Rod photoreceptor number is regulated by the locus lots-of-rods-junior (ljr) in the zebrafish retina Karen Alvarez-Delfin1*, Jason R. Willer2, Mailin Sotolongo-Lopez1 and James M. Fadool1 1 Florida State University, Biological Science Department, United States 2 University of Louisville, Department of Biochemistry and Molecular Biology, United States We are interested in the patterning and development of the vertebrate retina, and use the zebrafish (Danio rerio) embryo as a model. We have undertaken a large-scale genetics screen to identify mutations that alter photoreceptor cell number and mosaic pattern in free-swimming larvae. The locus lots-of-rods-junior (ljr) was identified in a screen of chemically mutagenized zebrafish. This study focuses on the characterization of the ljr mutant phenotype and the identification of the mutant gene. The number and distribution of the cones, rods, and most retinal cells in wild-type and ljr mutant larvae were analyzed in inmmunolabeled retinal sections. Cell cycle was examined by phospho-histone 3 (PH3) immunolabeling and BrdU incorporation in mutants and wild-types. Chromosome linkage was assigned using SSLP markers. The generation of high-resolution mapping was performed by generating additional polymorphic markers in the mutation interval. Cell autonomy was assayed by generating genetic chimeras by blastula cell transplants. ljr was identified by a four-fold increase in the number of rods at 4 dpf, when compared to wild-type siblings. Others photoreceptor and retinal cell types seem unaffected and no other morphologic alterations are evident in ljr homozygous mutant larvae or adults. PH3 immunolabeling and BrdU incorporation at different time-points do not reveal alteration in the mutants. ljr complemented lor, consistent with a mutation in a different locus. Linkage analysis positioned the ljr locus within a 0.5-Mb interval on chromosome 7. In genetics chimeras, ljr mutant cells fail to produce the increased number of rods phenotype in a wild-type host, suggesting a non-cell-autonomous function of the gene. This study validates the power of screening for alterations in photoreceptor patterning to uncover genes related to photoreceptor development. ljr is the second locus identified in zebrafish, after lor, which display an alteration in the photoreceptor cell number without cell death. Future investigations will comprise the fine mapping to identify the loci mutated in ljr. Conference: 2010 South East Nerve Net (SENN) and Georgia/South Carolina Neuroscience Consortium (GASCNC) conferences, Atlanta , United States, 5 Mar - 7 Mar, 2010. Presentation Type: Poster Presentation Topic: Posters Citation: Alvarez-Delfin K, Willer JR, Sotolongo-Lopez M and Fadool JM (2010). Rod photoreceptor number is regulated by the locus lots-of-rods-junior (ljr) in the zebrafish retina. Front. Neurosci. Conference Abstract: 2010 South East Nerve Net (SENN) and Georgia/South Carolina Neuroscience Consortium (GASCNC) conferences. doi: 10.3389/conf.fnins.2010.04.00011 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 15 Mar 2010; Published Online: 15 Mar 2010. * Correspondence: Karen Alvarez-Delfin, Florida State University, Biological Science Department, Tallahassee, United States, kalvarez@neuro.fsu.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Karen Alvarez-Delfin Jason R Willer Mailin Sotolongo-Lopez James M Fadool Google Karen Alvarez-Delfin Jason R Willer Mailin Sotolongo-Lopez James M Fadool Google Scholar Karen Alvarez-Delfin Jason R Willer Mailin Sotolongo-Lopez James M Fadool PubMed Karen Alvarez-Delfin Jason R Willer Mailin Sotolongo-Lopez James M Fadool Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.