PUBLICATION

EphA4 and EfnB2a maintain rhombomere coherence by independently regulating intercalation of progenitor cells in the zebrafish neural keel

Authors

Kemp, H.A., Cooke, J.E., and Moens, C.B.

ID

ZDB-PUB-090116-13

Date

2009

Source

Developmental Biology 327(2): 313-326 (Journal)

Registered Authors

Cooke, Julie E., Kemp, Hilary, Moens, Cecilia

Keywords

Eph, Ephrin, Efn, hindbrain, boundary, zebrafish, rhombomere, neuroepithelium, cell affinity, cell sorting

MeSH Terms

Cell Adhesion/physiology
Cell Differentiation/physiology
Female
Rhombencephalon*/cytology
Rhombencephalon*/embryology
Receptor, EphA4/genetics
Receptor, EphA4/metabolism*
Spindle Apparatus/metabolism
Cell Division/physiology
Humans
Ephrin-B2/genetics
Ephrin-B2/metabolism*
Animals
Zebrafish*/anatomy & histology
Zebrafish*/embryology
Zebrafish Proteins/genetics
Zebrafish Proteins/metabolism*
Morphogenesis/physiology*
Stem Cells/cytology
Stem Cells/physiology*
Male
Mosaicism

(all 22)

PubMed

19135438 Full text @ Dev. Biol.

Abstract

During vertebrate development, the hindbrain is transiently segmented into 7 distinct rhombomeres (r). Hindbrain segmentation takes place within the context of the complex morphogenesis required for neurulation, which in zebrafish involves a characteristic cross-midline division that distributes progenitor cells bilaterally in the forming neural tube. The Eph receptor tyrosine kinase EphA4 and the membrane-bound Ephrin (Efn) ligand EfnB2a, which are expressed in complementary segments in the early hindbrain, are required for rhombomere boundary formation. We showed previously that EphA4 promotes cell-cell affinity within r3 and r5, and proposed that preferential adhesion within rhombomeres contributes to boundary formation. Here we show that EfnB2a is similarly required in r4 for normal cell affinity and that EphA4 and EfnB2a regulate cell affinity independently within their respective rhombomeres. Live imaging of cell sorting in mosaic embryos shows that both proteins function during cross-midline cell divisions in the hindbrain neural keel. Consistent with this, mosaic EfnB2a over-expression causes widespread cell sorting and disrupts hindbrain organization, but only if induced at or before neural keel stage. We propose a model in which Eph and Efn-dependent cell affinity within rhombomeres serve to maintain rhombomere organization during the potentially disruptive process of teleost neurulation.

Genes / Markers

Figures

Show all Figures

Expression

Gene	Fish	Conditions	Stage	Anatomy	Assay	Figure
egr2b	WT	standard conditions	10-13 somites	neural crest	ISH	Fig. 3
egr2b	WT	standard conditions	5-9 somites	presumptive rhombomere 3	ISH	Fig. 3
egr2b	WT	standard conditions	5-9 somites	presumptive rhombomere 5	ISH	Fig. 3
egr2b	WT	standard conditions	10-13 somites	rhombomere 3	ISH	Fig. 3
egr2b	WT	standard conditions	14-19 somites	rhombomere 3	ISH	Fig. 3
egr2b	WT	standard conditions	14-19 somites	rhombomere 5	ISH	Fig. 3
egr2b	WT	standard conditions	10-13 somites	rhombomere 5	ISH	Fig. 3
egr2b	WT + MO1-epha4a + MO2-efnb2a	standard conditions	10-13 somites	neural crest	ISH	Fig. 3
egr2b	WT + MO1-epha4a + MO2-efnb2a	standard conditions	5-9 somites	presumptive rhombomere 3	ISH	Fig. 3
egr2b	WT + MO1-epha4a + MO2-efnb2a	standard conditions	5-9 somites	presumptive rhombomere 5	ISH	Fig. 3

1 - 10 of 14

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Phenotype

Fish	Conditions	Stage	Phenotype	Figure
WT + MO1-epha4a + MO2-efnb2a	standard conditions	5-9 somites	rhombomere 3 deformed, abnormal	Fig. 3
WT + MO1-epha4a + MO2-efnb2a	standard conditions	5-9 somites	rhombomere 5 deformed, abnormal	Fig. 3
WT + MO1-epha4a + MO2-efnb2a	standard conditions	5-9 somites	rhombomere boundary formation process quality, abnormal	Fig. 3
WT + MO1-epha4a + MO2-efnb2a	standard conditions	10-13 somites	rhombomere 3 deformed, abnormal	Fig. 3
WT + MO1-epha4a + MO2-efnb2a	standard conditions	10-13 somites	rhombomere 5 deformed, abnormal	Fig. 3
WT + MO1-epha4a + MO2-efnb2a	standard conditions	10-13 somites	rhombomere boundary formation process quality, abnormal	Fig. 3
WT + MO1-epha4a + MO2-efnb2a	standard conditions	14-19 somites	rhombomere 3 deformed, abnormal	Fig. 3
WT + MO1-epha4a + MO2-efnb2a	standard conditions	14-19 somites	rhombomere 5 deformed, abnormal	Fig. 3

1 - 8 of 8

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
e1Tg	Tg(pax2a:GFP)	Transgenic Insertion

Human Disease / Model

Sequence Targeting Reagents

Target	Reagent	Reagent Type
efnb2a	MO1-efnb2a	MRPHLNO
efnb2a	MO2-efnb2a	MRPHLNO
epha4a	MO1-epha4a	MRPHLNO

Fish

Fish
e1Tg
WT
WT + MO1-epha4a + MO2-efnb2a

Antibodies

Orthology

Engineered Foreign Genes

Marker	Marker Type	Name
GFP	EFG	GFP

Mapping

Kemp et al., 2009 ZDB-PUB-090116-13 PMID:19135438

EphA4 and EfnB2a maintain rhombomere coherence by independently regulating intercalation of progenitor cells in the zebrafish neural keel

Kemp et al., 2009

ZDB-PUB-090116-13
PMID:19135438