PUBLICATION

Discontinuous organization and specification of the lateral floor plate in zebrafish

Authors

Schafer, M., Kinzel, D., and Winkler, C.

ID

ZDB-PUB-061020-47

Date

2007

Source

Developmental Biology 301(1): 117-129 (Journal)

Registered Authors

Schafer, Matthias, Winkler, Christoph

Keywords

Neural patterning, Floor plate formation, Hedgehog signaling, Nkx2.2, Homeobox genes

MeSH Terms

Animals
Hedgehog Proteins/metabolism
Nervous System/embryology
Nervous System/metabolism
Signal Transduction
Body Patterning*
Receptors, Notch/genetics
Receptors, Notch/metabolism
Gene Expression Profiling
Base Sequence
Zebrafish
DNA Primers

(all 12)

PubMed

17045256 Full text @ Dev. Biol.

Abstract

The floor plate is a signaling center in the ventral neural tube of vertebrates with important functions during neural patterning and axon guidance. It is composed of a centrally located medial floor plate (MFP) and a bilaterally positioned lateral floor plate (LFP). While the role of the MFP as source of signaling molecules like, e.g., Sonic Hedgehog (Shh) is well understood, the exact organization and function of the LFP are currently unclear. Based on expression analyses, the one cell wide LFP in zebrafish has been postulated to be a homogenous structure. We instead show that the zebrafish trunk LFP is discontinuously arranged. Single LFP cells alternate with p3 neuronal precursor cells, which develop V3 interneurons along the anteroposterior (AP) axis. Our mutant analyses indicate that both, formation of LFP and p3 cells require Delta-Notch signaling. Importantly, however, the two cell types are differentially regulated by Hedgehog (HH) and Nkx2.2 activities. This implicates a novel mechanism of neural tube patterning, in which distinct cell populations within one domain of the ventral neural tube are differently specified along the AP axis. We conclude that different levels of HH and Nkx2.2 activities are responsible for the alternating appearance of LFP and p3 neuronal progenitor cells in the zebrafish ventral neural tube.

Genes / Markers

Figures

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Expression

Phenotype

Fish	Conditions	Stage	Phenotype	Figure
WT + MO1-nkx2.2a	standard conditions	14-19 somites	floor plate formation disrupted, abnormal	Fig. 7
WT + MO1-nkx2.2a	standard conditions	14-19 somites	lateral floor plate composition, abnormal	Fig. 7
gli1^te370a/+	standard conditions	14-19 somites	floor plate formation disrupted, abnormal	Fig. 4
gli1^te370a/+	standard conditions	14-19 somites	floor plate formation disrupted, abnormal	Fig. 5
gli1^te370a/+	standard conditions	14-19 somites	lateral floor plate composition, abnormal	Fig. 4
gli1^te370a/+	standard conditions	14-19 somites	lateral floor plate composition, abnormal	Fig. 5
gli1^{te370a/te370a}	standard conditions	14-19 somites	floor plate formation disrupted, abnormal	Fig. 4
gli1^{te370a/te370a}	standard conditions	14-19 somites	floor plate formation disrupted, abnormal	Fig. 5
gli1^{te370a/te370a}	standard conditions	14-19 somites	lateral floor plate composition, abnormal	Fig. 4
gli1^{te370a/te370a}	standard conditions	14-19 somites	lateral floor plate composition, abnormal	Fig. 5

1 - 10 of 17

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Mutations / Transgenics

Allele	Type	Affected Genomic Region
b641	Point Mutation	smo
t4	Deficiency	shha
ta52b	Point Mutation	mib1
te370a	Point Mutation	gli1
ty17a	Point Mutation	gli2a
ty119	Point Mutation	gli2a

1 - 6 of 6

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Human Disease / Model

Sequence Targeting Reagents

Target	Reagent	Reagent Type
nkx2.2a	MO1-nkx2.2a	MRPHLNO
nkx2.2b	MO1-nkx2.2b	MRPHLNO

Fish

Fish
Df(Chr07)t4/+
gli1^te370a/+
gli1^{te370a/te370a}
gli2a^ty17a/+
gli2a^ty17a/ty17a
gli2a^ty119/ty119
mib1^ta52b/ta52b
smo^b641/+
WT
WT + MO1-nkx2.2a

Antibodies

Orthology

Engineered Foreign Genes

Mapping

Schafer et al., 2007 ZDB-PUB-061020-47 PMID:17045256

Discontinuous organization and specification of the lateral floor plate in zebrafish

Schafer et al., 2007

ZDB-PUB-061020-47
PMID:17045256