Our long term goal is to understand how cells are specified to form the ear. The inner ear arises from the otic placode. Previous studies suggest that inductive signals from neighboring tissues specify formation of the placode. However, it is unknown how cells are allocated to the placode or how they respond to the signals that trigger their differentiation into the ear. We have identified a zebrafish mutant that lacks a detectable otic placode and fails to form an ear. The mutation is a deficiency of the closely linked dlx3 and dlx7 genes. We propose to use this mutation to analyze the cellular interactions required to form the placode and the potential roles of these genes in this process. 1. We will test the hypothesis that function of the dlx3-dlx7 genes is required for formation of the ear. To learn whether expression of dlx3-dlx7 is necessary to form the ear, we will isolate point mutations in these genes. To learn whether dlx3-dlx7 expression is sufficient, we will rescue the mutant phenotype with wild-type transgenes. These experiments will elucidate the functions of dlx3-dlx7 in specification of otic placode cells. 2. We will test the hypothesis that the dlx3-dlx7 genes function to specify the competence of cells to form the ear. This hypothesis predicts the mutation should autonomously affect cells that form the placode. We will identify which cells the mutation affects by generating genetic mosaics. This analysis will tell us in which cells the dlx3-dlx7 genes normally act. We will use small groups of competent cells from wild-type hosts as probes to learn the locations of signaling cells in mutant hosts. We will then transplant wild-type cells into these locations in dlx3-dlx7 mutants at various developmental stages. These experiments will reveal which cells signal induction of the placode and at what developmental time the induction occurs. 3. We will screen for mutations in genes that encode the inductive signal and signal response system that are required to form the otic placode. We will screen for mutations that block formation of the otic placodes. We will characterize these mutations phenotypically and genetically. This analysis will identify genes on the basis of their functions in specifying the fates of cells that form the otic placodes. This application is part of an IRPG to understand the mechanisms that regulate morphogenesis and cell specification in the vertebrate inner ear.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC004186-03
Application #
6379504
Study Section
Special Emphasis Panel (ZRG1-IFCN-6 (01))
Program Officer
Freeman, Nancy
Project Start
1999-08-01
Project End
2004-07-31
Budget Start
2001-08-01
Budget End
2002-07-31
Support Year
3
Fiscal Year
2001
Total Cost
$313,374
Indirect Cost
Name
University of Oregon
Department
Neurosciences
Type
Schools of Arts and Sciences
DUNS #
948117312
City
Eugene
State
OR
Country
United States
Zip Code
97403
Dona, Margo; Slijkerman, Ralph; Lerner, Kimberly et al. (2018) Usherin defects lead to early-onset retinal dysfunction in zebrafish. Exp Eye Res 173:148-159
Blanco-Sánchez, Bernardo; Clément, Aurélie; Fierro Jr, Javier et al. (2018) Grxcr1 Promotes Hair Bundle Development by Destabilizing the Physical Interaction between Harmonin and Sans Usher Syndrome Proteins. Cell Rep 25:1281-1291.e4
Li, Tongchao; Fan, Junkai; Blanco-Sánchez, Bernardo et al. (2016) Ubr3, a Novel Modulator of Hh Signaling Affects the Degradation of Costal-2 and Kif7 through Poly-ubiquitination. PLoS Genet 12:e1006054
Beck, Bodo B; Phillips, Jennifer B; Bartram, Malte P et al. (2014) Mutation of POC1B in a severe syndromic retinal ciliopathy. Hum Mutat 35:1153-62
Phillips, Jennifer B; Westerfield, Monte (2014) Zebrafish models in translational research: tipping the scales toward advancements in human health. Dis Model Mech 7:739-43
Blanco-Sánchez, Bernardo; Clément, Aurélie; Fierro Jr, Javier et al. (2014) Complexes of Usher proteins preassemble at the endoplasmic reticulum and are required for trafficking and ER homeostasis. Dis Model Mech 7:547-59
Phillips, Jennifer B; Västinsalo, Hanna; Wegner, Jeremy et al. (2013) The cone-dominant retina and the inner ear of zebrafish express the ortholog of CLRN1, the causative gene of human Usher syndrome type 3A. Gene Expr Patterns 13:473-81
Gao, Jingxia; Zhang, Changwen; Yang, Bin et al. (2012) Dcc regulates asymmetric outgrowth of forebrain neurons in zebrafish. PLoS One 7:e36516
Phillips, Jennifer B; Blanco-Sanchez, Bernardo; Lentz, Jennifer J et al. (2011) Harmonin (Ush1c) is required in zebrafish Muller glial cells for photoreceptor synaptic development and function. Dis Model Mech 4:786-800
Zhang, Chao; Song, Youngsup; Thompson, Darren A et al. (2010) Pineal-specific agouti protein regulates teleost background adaptation. Proc Natl Acad Sci U S A 107:20164-71

Showing the most recent 10 out of 29 publications