ZFIN ID: ZDB-PUB-060517-7
Proneural gene requirement for hair cell differentiation in the zebrafish lateral line
Sarrazin, A.F., Villablanca, E.J., Nunez, V.A., Sandoval, P.C., Ghysen, A., and Allende, M.L.
Date: 2006
Source: Developmental Biology 295(2): 534-545 (Journal)
Registered Authors: Allende, Miguel L.
Keywords: Lateral line, Neuromasts, Hair cells, Proneural genes, bHLH, Atonal homolog, NeuroD
MeSH Terms: Animals; Basic Helix-Loop-Helix Transcription Factors/genetics*; Cell Differentiation/genetics*; Cell Lineage; Gene Expression Regulation/physiology; Hair Cells, Auditory/cytology*; Mechanoreceptors*; Nerve Tissue Proteins/genetics*; Signal Transduction/genetics; Transcription Factors/genetics*; Zebrafish; Zebrafish Proteins/genetics*
PubMed: 16678150 Full text @ Dev. Biol.
FIGURES   (current status)
ABSTRACT
The lateral line system comprises an array of mechanosensory organs, the neuromasts, distributed over the body surface. Each neuromast consists of a patch of mechanosensory hair cells surrounded by support cells. We show that, in the zebrafish, two proneural genes are essential for differentiation of the hair cells, neuroD (nrd) and atonal homolog 1 (ath1). Gene knockdown experiments demonstrate that loss of function of either gene, but not of the related proneural gene neurogenin1 (ngn1), abrogate the appearance of hair cell markers. This is in contrast to other sensory systems, such as the neurons of the lateral line ganglion, where nrd is regulated by ngn1 and not by ath1. Overexpression of ath1 can induce nrd, and the phenotype produced by loss of ath1 function can be partially rescued by injection of nrd mRNA. This supports the conclusion that the activation of nrd probably requires ath1 in the hair cell lineage, whereas in sensory neurons nrd activation requires ngn1. We propose that the emergence of two atonal homologs, ath1 and ngn1, allowed the cellular segregation of mechanoreception and signal transmission that were originally performed by a single cell type as found in insects.
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