PUBLICATION

Loss of the RNA-binding protein Rbm15 disrupts liver maturation in zebrafish

Authors

Hu, L., Li, H., Chi, Z., He, J.

ID

ZDB-PUB-200611-4

Date

2020

Source

The Journal of biological chemistry 295(33): 11466-11472 (Journal)

Registered Authors

He, Jianbo

Keywords

RNA binding motif protein 15 (Rbm15), RNA binding protein, gene regulation, hepatocyte nuclear factor 4 (HNF-4), liver maturation, liver organogenesis, mTORC1, post-transcriptional regulation, zebrafish

MeSH Terms

Liver/cytology
Liver/embryology*
Zebrafish/embryology*
Zebrafish/genetics
Apoptosis
Hepatocytes/cytology
Hepatocytes/metabolism
Cell Proliferation
Gene Deletion*
Cell Differentiation
CRISPR-Cas Systems
Gene Expression Regulation, Developmental*
Animals

(all 13)

PubMed

32518161 Full text @ J. Biol. Chem.

Abstract

Liver organogenesis begins with hepatic precursors in the foregut endoderm, followed by hepatoblast specification, differentiation, outgrowth, and maturation for the formation of functional hepatocytes. Although several signaling pathways and critical factors that regulate liver specification, differentiation, and proliferation have been identified, little is known about how liver maturation is regulated. Here, we used a screen for mutations affecting liver development in zebrafish and identified a cq96 mutant that exhibits a specific defect in liver maturation. Results from positional cloning revealed that cq96 encodes an RNA-binding protein, Rbm15, which is an evolutionarily conserved Spen family protein and known to play a crucial role in RNA m6A modification, nuclear export, and alternative splicing. However, a function of Rbm15 in embryonic liver development has not been reported. We found that Rbm15 is specifically expressed in the liver after its differentiation. CRISPR/Cas9-mediated loss of rbm15 repressed hepatic maturation, but did not affect hepatoblast specification, differentiation, and hepatocyte proliferation and apoptosis. Additional experiments disclosed that the mTOR complex 1 (mTORC1) pathway is highly activated in rbm15-deficient hepatocytes. Moreover, rapamycin treatment partially restored normal hepatic gene expression as well as the nuclear location of the transcription factor Hnf4a. Taken together, these results reveal an unexpected role of Rbm15 in liver maturation.

Genes / Markers

Figures

Show all Figures

Expression

Gene	Fish	Conditions	Stage	Anatomy	Assay	Figure
cp	rbm15^cq96/cq96	standard conditions	Day 5	hepatocyte	ISH	Figure 1.
cp	rbm15^cq96/cq96	standard conditions	Days 7-13	liver	ISH	Figure 5.
cp	rbm15^cq96/cq96	heat shock	Days 7-13	liver	ISH	Figure 2.
cp	rbm15^cq96/cq96	chemical treatment by environment: sirolimus	Days 7-13	liver	ISH	Figure 5.
cp	rbm15^cq96/cq96; cq97Tg	heat shock	Days 7-13	liver	ISH	Figure 2.
cp	WT	standard conditions	Days 7-13	hepatocyte	ISH	Figure 5.
cp	WT	standard conditions	Day 5	hepatocyte	ISH	Figure 1.
cp	WT	heat shock	Days 7-13	liver	ISH	Figure 2.
Dendra2	cq1Tg	standard conditions	Day 5	liver	IFL	Figure 1.
Dendra2	cq1Tg	standard conditions	Days 7-13	liver	IFL	Figure 5.

1 - 10 of 48

Show

Phenotype

Fish	Conditions	Stage	Phenotype	Figure
rbm15^cq96/cq96	standard conditions	Day 5	hepatocyte cp expression decreased amount, abnormal	Figure 1.
rbm15^cq96/cq96	standard conditions	Day 5	hepatocyte gc expression decreased amount, abnormal	Figure 1.
rbm15^cq96/cq96	standard conditions	Day 5	hepatocyte gys2 expression decreased amount, abnormal	Fig. S1
rbm15^cq96/cq96	standard conditions	Day 5	hepatocyte uox expression decreased amount, abnormal	Figure 1.
rbm15^cq96/cq96	standard conditions	Day 5	liver ab-2f11 labeling increased amount, abnormal	Figure 5.
rbm15^cq96/cq96	standard conditions	Days 7-13	liver cp expression decreased amount, abnormal	Figure 5.
rbm15^cq96/cq96	standard conditions	Days 7-13	liver gc expression decreased amount, abnormal	Figure 5.
rbm15^cq96/cq96	chemical treatment by environment: sirolimus	Days 7-13	liver cp expression amount, ameliorated	Figure 5.
rbm15^cq96/cq96	chemical treatment by environment: sirolimus	Days 7-13	liver gc expression amount, ameliorated	Figure 5.
rbm15^cq96/cq96	heat shock	Days 7-13	liver cp expression decreased amount, abnormal	Figure 2.

1 - 10 of 19

Show

Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
cq1Tg	Tg(fabp10a:Dendra2-NTR)	Transgenic Insertion
cq96		Small Deletion	rbm15
cq97Tg	Tg(hsp70l:rbm15-FLAG)	Transgenic Insertion

Human Disease / Model

Sequence Targeting Reagents

Target	Reagent	Reagent Type
rbm15	CRISPR1-rbm15	CRISPR

Fish

Fish
cq1Tg
cq1Tg; cq97Tg
rbm15^cq96/cq96
rbm15^cq96/cq96; cq1Tg
rbm15^cq96/cq96; cq1Tg; cq97Tg
rbm15^cq96/cq96; cq97Tg
WT

Antibodies

Name	Type	Antigen Genes	Isotypes	Host Organism
Ab1-eif4ebp1	monoclonal	eif4ebp1	IgG	Rabbit
ab1-hnf4a	polyclonal	hnf4a	IgG	Goat
Ab-2F11	monoclonal	anxa4	IgG1	Mouse
Ab3-prox1	polyclonal	prox1a		Rabbit
Ab10-pcna	polyclonal			Rabbit

1 - 5 of 5

Show

Orthology

Engineered Foreign Genes

Marker	Marker Type	Name
Dendra2	EFG	Dendra2
NTR	EFG	NTR

Mapping

Hu et al., 2020 ZDB-PUB-200611-4 PMID:32518161

Loss of the RNA-binding protein Rbm15 disrupts liver maturation in zebrafish

Hu et al., 2020

ZDB-PUB-200611-4
PMID:32518161