PUBLICATION

Vegetally localised Vrtn functions as a novel repressor to modulate bmp2b transcription during dorsoventral patterning in zebrafish.

Authors

Shao, M., Wang, M., Liu, Y.Y., Ge, Y.W., Zhang, Y.J., Shi, D.L.

ID

ZDB-PUB-170921-8

Date

2017

Source

Development (Cambridge, England) 144: 3361-3374 (Journal)

Registered Authors

Shao, Ming, Shi, De-Li

Keywords

BMP signalling, Bmp2b, Dorsoventral patterning, Vegetal maternal determinants, Vrtn, Zebrafish

Datasets

GEO:GSE103090

MeSH Terms

Base Sequence
RNA, Messenger/genetics
RNA, Messenger/metabolism
Mutation/genetics
Models, Biological
Chlorocebus aethiops
Embryo, Nonmammalian/cytology
Embryo, Nonmammalian/metabolism
Bone Morphogenetic Protein 2/genetics*
Bone Morphogenetic Protein 2/metabolism
Zebrafish/embryology*
Zebrafish/genetics
Protein Binding/genetics
Gene Expression Regulation, Developmental
Transcription, Genetic
Zebrafish Proteins/genetics
Zebrafish Proteins/metabolism*
Body Patterning*/genetics
Zygote/metabolism
Animals
Repressor Proteins/genetics
Repressor Proteins/metabolism*
Egg Yolk/metabolism*
COS Cells
Wnt Signaling Pathway/genetics

(all 25)

PubMed

28928283 Full text @ Development

Abstract

The vegetal pole cytoplasm represents a crucial source of maternal dorsal determinants for patterning the dorsoventral axis of the early embryo. Removal of the vegetal yolk in the zebrafish fertilised egg before the completion of the first cleavage results in embryonic ventralisation, but removal of this part at the two-cell stage leads to embryonic dorsalisation. How this is achieved remains unknown. Here, we report a novel mode of maternal regulation of BMP signalling during dorsoventral patterning in zebrafish. We identify Vrtn as a novel vegetally localised maternal factor with dorsalising activity and rapid transport towards the animal pole region after fertilisation. Co-injection of vrtn mRNA with vegetal RNAs from different cleavage stages suggests the presence of putative vegetally localised Vrtn antagonists with slower animal pole transport. Thus, vegetal ablation at the two-cell stage could remove most of the Vrtn antagonists, and allows Vrtn to produce the dorsalising effect. Mechanistically, Vrtn binds a bmp2b regulatory sequence and acts as a repressor to inhibit its zygotic transcription. Analysis of maternal-zygotic vrtn mutants further shows that Vrtn is required to constrain excessive bmp2b expression in the margin. Our work unveils a novel maternal mechanism regulating zygotic BMP gradient in dorsoventral patterning.

Genes / Markers

Figures

Show all Figures

Expression

Gene	Fish	Conditions	Stage	Anatomy	Assay	Figure
bmp2b	vrtn^sdu1/sdu1	standard conditions	50%-epiboly	anatomical structure	ISH	Fig. 5
bmp2b	vrtn^sdu1/sdu1	ablation: yolk	Shield	margin	ISH	Fig. 5
bmp2b	vrtn^sdu1/sdu1	ablation: yolk	Shield	margin	RTPCR	Fig. 5
bmp2b	vrtn^sdu1/sdu1	standard conditions	50%-epiboly	whole organism	RTPCR	Fig. 5
bmp2b	WT	standard conditions	50%-epiboly	anatomical structure	ISH	Fig. 5
bmp2b	WT	standard conditions	75%-epiboly	blastoderm cell	ISH	Fig. 2
bmp2b	WT	ablation: yolk	75%-epiboly	internal yolk syncytial layer	ISH	Fig. 2
bmp2b	WT	standard conditions	50%-epiboly	margin	ISH	Fig. 2
bmp2b	WT	ablation: yolk	Shield	margin	ISH	Fig. 2
bmp2b	WT	ablation: yolk	50%-epiboly	margin	ISH	Fig. 2

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Phenotype

Fish	Conditions	Stage	Phenotype	Figure
WT	ablation: yolk	32-cell	blastodisc anatomical margin vrtn expression decreased amount, abnormal	Fig. 3
WT	ablation: yolk	32-cell	whole organism vrtn expression decreased amount, abnormal	Fig. 3
WT	ablation: yolk	Germ-ring to Shield	anatomical structure bmp4 expression decreased amount, abnormal	Fig. 2
WT	ablation: yolk	Shield	anatomical structure eve1 expression decreased amount, abnormal	Fig. 1
WT	ablation: yolk	Germ-ring to Shield	anatomical structure gata2a expression decreased amount, abnormal	Fig. 1
WT	ablation: yolk	Germ-ring to Shield	anatomical structure gsc expression decreased amount, abnormal	Fig. 1
WT	ablation: yolk	Germ-ring to Shield	anatomical structure gsc expression spatial pattern, abnormal	Fig. 1
WT	ablation: yolk	50%-epiboly to Shield	anatomical structure ab1-smad labeling decreased amount, abnormal	Fig. 1
WT	ablation: yolk	50%-epiboly to Shield	BMP signaling pathway decreased occurrence, abnormal	Fig. 1
WT	ablation: yolk	Shield	BMP signaling pathway decreased occurrence, abnormal	Fig. 1

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
sdu1		Small Deletion	vrtn

Human Disease / Model

Sequence Targeting Reagents

Target	Reagent	Reagent Type
bmp2b	MO1-bmp2b	MRPHLNO
ctnnb2	MO1-ctnnb2	MRPHLNO
vrtn	CRISPR1-vrtn	CRISPR
vrtn	MO1-vrtn	MRPHLNO

Fish

Fish
vrtn^sdu1/sdu1
vrtn^sdu1
WT
WT + MO1-vrtn

Antibodies

Name	Type	Antigen Genes	Isotypes	Host Organism
Ab1-myc	monoclonal		IgG1	Mouse
Ab1-smad	polyclonal	smad1 smad5 smad9	IgG	Rabbit
Ab14-ctnnb	polyclonal		IgG	Rabbit

Orthology

Engineered Foreign Genes

Mapping

Shao et al., 2017 ZDB-PUB-170921-8 PMID:28928283

Vegetally localised Vrtn functions as a novel repressor to modulate bmp2b transcription during dorsoventral patterning in zebrafish.

Shao et al., 2017

ZDB-PUB-170921-8
PMID:28928283