PUBLICATION

The homeobox gene irx1a is required for the propagation of the neurogenic waves in the zebrafish retina

Authors

Cheng, C.W., Yan, C.H., Hui, C.C., Strähle, U., and Cheng, S.H.

ID

ZDB-PUB-060210-6

Date

2006

Source

Mechanisms of Development 123(3): 252-263 (Journal)

Registered Authors

Cheng, Shuk Han, Strähle, Uwe

Keywords

Zebrafish, Retinogenesis, Wave propagation, Iroquois, Sonic hedgehog

MeSH Terms

Signal Transduction
Zebrafish Proteins/genetics*
Zebrafish Proteins/metabolism
Retina/cytology
Retina/embryology*
Retina/metabolism
Gene Expression Regulation, Developmental
Animals
Hedgehog Proteins/genetics
Hedgehog Proteins/metabolism
Animals, Genetically Modified
Zebrafish
Fibroblast Growth Factors/metabolism
Eye Diseases/genetics
Eye Diseases/metabolism
Retinal Ganglion Cells/metabolism*
Cell Differentiation
Transcription Factors/genetics*
Transcription Factors/metabolism
Eye/embryology*
Homeodomain Proteins/genetics*
Homeodomain Proteins/metabolism

(all 22)

PubMed

16457994 Full text @ Mech. Dev.

Abstract

Neurogenesis in the compound eyes of Drosophila and the camera eyes of vertebrates spreads in a wave-like fashion. In both phyla, waves of hedgehog expression are known to drive the wave of neuronal differentiation. The mechanism controlling the propagation of hedgehog expression during retinogenesis of the vertebrate eye is poorly understood. The Iroquois homeobox genes play important roles in Drosophila eye development; they are required for the up-regulation of hedgehog expression during propagation of the morphogenetic furrow. Here, we show that the zebrafish Iroquois homolog irx1a is expressed during retinogenesis and knockdown of irx1a results in a retinal phenotype strikingly similar to those of sonic hedgehog (shh) mutants. Analysis of shh-GFP transgene expression in irx1a knockdown retinas revealed that irx1a is required for the propagation of shh expression through the retina. Transplantation experiments illustrated that the effects of irx1a on shh expression are both cell-autonomous and non-cell-autonomous. Our results reveal a role for Iroquois genes in controlling hedgehog expression during vertebrate retinogenesis.

Genes / Markers

Figures

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Expression

Gene	Fish	Conditions	Stage	Anatomy	Assay	Figure
atoh7	WT	standard conditions	Prim-5	presumptive neural retina	ISH	Fig. 1
atoh7	WT	standard conditions	Prim-15	retina	ISH	Fig. 1
atoh7	WT	standard conditions	Prim-25	retina	ISH	Fig. 1
atoh7	WT	control	Long-pec	retina	ISH	Fig. 4
atoh7	WT	control	Long-pec	retina	ISH	Fig. 7
atoh7	WT	chemical treatment: Cyclopamine	Long-pec	retina	ISH	Fig. 7
atoh7	WT + MO2-irx1a	standard conditions	Long-pec	ciliary marginal zone	ISH	Fig. 4
atoh7	WT + MO2-irx1a	standard conditions	Long-pec	retina	ISH	Fig. 4
atoh7	WT + MO3-irx1a	standard conditions	Long-pec	ciliary marginal zone	ISH	Fig. 4
atoh7	WT + MO3-irx1a	standard conditions	Long-pec	retina	ISH	Fig. 4

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Phenotype

Fish	Conditions	Stage	Phenotype	Figure
WT + MO2-irx1a	standard conditions	Long-pec	cell death increased rate, abnormal	Fig. 3
WT + MO2-irx1a	standard conditions	Long-pec	cell population proliferation increased rate, abnormal	Fig. 3
WT + MO2-irx1a	standard conditions	Long-pec	cranial nerve II malformed, abnormal	Fig. 4
WT + MO2-irx1a	standard conditions	Long-pec	eye photoreceptor cell differentiation disrupted, abnormal	Fig. 4
WT + MO2-irx1a	standard conditions	Long-pec	retina development in camera-type eye disrupted, abnormal	Fig. 4
WT + MO2-irx1a	standard conditions	Long-pec	retina malformed, abnormal	Fig. 3
WT + MO2-irx1a	standard conditions	Long-pec	retina malformed, abnormal	Fig. 4
WT + MO2-irx1a	standard conditions	Long-pec	retinal ganglion cell decreased amount, abnormal	Fig. 4
WT + MO2-irx1a	standard conditions	Day 4	amacrine cell decreased amount, abnormal	Fig. 5
WT + MO2-irx1a	standard conditions	Day 4	eye decreased size, abnormal	Fig. 2

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
sb28Tg	Tg(-2.4shha-ABC:GFP)	Transgenic Insertion

Human Disease / Model

Sequence Targeting Reagents

Target	Reagent	Reagent Type
irx1a	MO2-irx1a	MRPHLNO
irx1a	MO3-irx1a	MRPHLNO

Fish

Fish
sb28Tg
sb28Tg + MO2-irx1a
sb28Tg + MO3-irx1a
WT
WT + MO2-irx1a
WT + MO3-irx1a

Antibodies

Orthology

Engineered Foreign Genes

Marker	Marker Type	Name
GFP	EFG	GFP

Mapping

Cheng et al., 2006 ZDB-PUB-060210-6 PMID:16457994

The homeobox gene irx1a is required for the propagation of the neurogenic waves in the zebrafish retina

Cheng et al., 2006

ZDB-PUB-060210-6
PMID:16457994