PUBLICATION

Protocadherin-Mediated Cell Repulsion Controls the Central Topography and Efferent Projections of the Abducens Nucleus

Authors

Asakawa, K., Kawakami, K.

ID

ZDB-PUB-180809-8

Date

2018

Source

Cell Reports 24: 1562-1572 (Journal)

Registered Authors

Asakawa, Kazuhide, Kawakami, Koichi

Keywords

DRS, lateral rectus, mafb, mnr2b, motor neuron, pcdh17, rhombomere, sall4, strabismus, zebrafish

MeSH Terms

Humans
Brain Stem/metabolism*
Zebrafish
Animals
Abducens Nucleus/physiopathology*

PubMed

30089266 Full text @ Cell Rep.

Abstract

Cranial motor nuclei in the brainstem innervate diverse types of head and neck muscles. Failure in establishing these neuromuscular connections causes congenital cranial dysinnervation disorders (CCDDs) characterized by abnormal craniofacial movements. However, mechanisms that link cranial motor nuclei to target muscles are poorly understood at the molecular level. Here, we report that protocadherin-mediated repulsion mediates neuromuscular connection in the ocular motor system in zebrafish. We identify pools of abducens motor neurons that are topographically arranged according to soma size and convergently innervate a single muscle. Disruptions of Duane retraction syndrome-associated transcription factors reveal that these neurons require Mafba/MAFB, but not Sall4/SALL4, for differentiation. Furthermore, genetic perturbations of Pcdh17/protocadherin-17 result in defective axon growth and soma clumping, thereby abolishing neuromuscular connectivity. Our results suggest that protocadherin-mediated repulsion forms the central topography and efferent projection pattern of the abducens nucleus following Mafba-dependent specification and imply potential involvement of protocadherins in CCDD etiology.

Genes / Markers

Figures

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Expression

Gene	Fish	Conditions	Stage	Qualifier	Anatomy	Assay	Figure
EGFP	mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	control	Protruding-mouth	Not Detected	rhombomere 5 abducens motor nucleus	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	control	Protruding-mouth	Not Detected	rhombomere 6 abducens motor nucleus	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	control	Protruding-mouth		spinal cord motor neuron	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	control	Protruding-mouth		ventral root	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkuasgfp1aTg	control	Prim-5		rhombomere 5	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkuasgfp1aTg	control	Prim-5		rhombomere 6	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/+}; nkhgj4aEt	control	Protruding-mouth	Not Detected	rhombomere 5 abducens motor nucleus	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/+}; nkhgj4aEt	control	Protruding-mouth	Not Detected	rhombomere 6 abducens motor nucleus	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/+}; nkhgj4aEt	control	Protruding-mouth		spinal cord motor neuron	IFL	Fig. 4
EGFP	mafba^{nkgsaizgffm35aGt/+}; nkhgj4aEt	control	Protruding-mouth		ventral root	IFL	Fig. 4

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Phenotype

Fish	Conditions	Stage	Phenotype	Figure
mafba^{nkgsaizgffm35aGt/+}; nkhgj4aEt	control	Protruding-mouth	rhombomere 5 abducens motor nucleus EGFP expression absent, abnormal	Fig. 4
mafba^{nkgsaizgffm35aGt/+}; nkhgj4aEt	control	Protruding-mouth	rhombomere 6 abducens motor nucleus EGFP expression absent, abnormal	Fig. 4
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	control	Protruding-mouth	rhombomere 5 abducens motor nucleus EGFP expression absent, abnormal	Fig. 4
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	control	Protruding-mouth	rhombomere 6 abducens motor nucleus EGFP expression absent, abnormal	Fig. 4
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	standard conditions	Protruding-mouth	rhombomere 5 abducens motor nucleus absent, abnormal	Fig. 4
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt	standard conditions	Protruding-mouth	rhombomere 6 abducens motor nucleus absent, abnormal	Fig. 4
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkuasgfp1aTg	control	Prim-5	rhombomere 5 vestigial, abnormal	Fig. 4
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkuasgfp1aTg	control	Prim-5	rhombomere 6 vestigial, abnormal	Fig. 4
nkegfpuaspcdh17dcprTg; nkmnr2bhsga14Tg	control	Protruding-mouth	abducens motor nucleus axon defasciculated, abnormal	Fig. 6
nkegfpuaspcdh17dcprTg; nkmnr2bhsga14Tg	control	Protruding-mouth	abducens motor nucleus axon extension decreased occurrence, abnormal	Fig. 6

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
nk73aGt	Gt(GAL4FF)	Transgenic Insertion
nkactc1btdTchrndTg	Tg(actc1b-hsp70l:Tomato-chrnd)	Transgenic Insertion
nkegfpuaspcdh17dcprTg	Tg(4xUAS:dnpcdh17-mRFP1,EGFP)	Transgenic Insertion
nkegfpuaspcdh17dcptrTg	Tg2(4xUAS:pcdh17-mRFP1,EGFP)	Transgenic Insertion
nkegfpuaspcdh17flrTg	Tg(4xUAS:pcdh17-mRFP1,EGFP)	Transgenic Insertion
nkegr2bcreTg	TgBAC(egr2b:Cre)	Transgenic Insertion
nkgsaizgffm35aGt	Gt(gSAIz-GAL4FFM)	Transgenic Insertion	mafba
nkgsaizgffm773bGt	Gt(gSAIz-GAL4FFM)	Transgenic Insertion
nkgsaizgffm1068aGt	Gt(gSAIz-GAL4FFM)	Transgenic Insertion
nkhgj4aEt	Et(T2KHG)	Transgenic Insertion

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Human Disease / Model

Sequence Targeting Reagents

Target	Reagent	Reagent Type
pcdh17	CRISPR1-pcdh17	CRISPR
sall4	CRISPR1-sall4	CRISPR

Fish

Fish
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkhgj4aEt
mafba^{nkgsaizgffm35aGt/nkgsaizgffm35aGt}; nkuasgfp1aTg
mafba^{nkgsaizgffm35aGt/+}; nkhgj4aEt
mafba^{nkgsaizgffm35aGt/+}; nkuasgfp1aTg
nkactc1btdTchrndTg; nkegr2bcreTg; nkmnr2bhsga14Tg; nkuasloxgloxrTg
nkactc1btdTchrndTg; nkegr2bcreTg; nkmnr2bhsga14Tg; nkuasloxrloxgTg
nkactc1btdTchrndTg; nkmnr2bhsga14Tg; nkuasgfp1aTg
nkactc1btdTchrndTg; nkmnr2bhsga14Tg; nkuasv2vTg
nkegfpuaspcdh17dcprTg; nkmnr2bhsga14Tg
nkegfpuaspcdh17flrTg; nkmnr2bhsga14Tg

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Antibodies

Orthology

Engineered Foreign Genes

Marker	Marker Type	Name
Cre	EFG	Cre
EGFP	EFG	EGFP
GAL4FF	EFG	GAL4FF
Kaede	EFG	Kaede
mRFP1	EFG	mRFP1
RFP	EFG	RFP
Tomato	EFG	Tomato
Venus	EFG	Venus

Mapping

Asakawa et al., 2018 ZDB-PUB-180809-8 PMID:30089266

Protocadherin-Mediated Cell Repulsion Controls the Central Topography and Efferent Projections of the Abducens Nucleus

Asakawa et al., 2018

ZDB-PUB-180809-8
PMID:30089266