PUBLICATION

CERKL gene knockout disturbs photoreceptor outer segment phagocytosis and causes rod-cone dystrophy in zebrafish

Authors

Yu, S., Li, C., Biswas, L., Hu, X., Liu, F., Reilly, J., Liu, X., Liu, Y., Huang, Y., Lu, Z., Han, S., Wang, L., Liu, J.Y., Jiang, T., Shu, X., Wong, F., Tang, Z., Liu, M.

ID

ZDB-PUB-170412-3

Date

2017

Source

Human molecular genetics 26(12): 2335-2345 (Journal)

Registered Authors

Han, Shanshan, Huang, Yuwen, Hu, Xuebin, Li, Chang, Liu, Fei, Liu, Mugen, Liu, Xiliang, Liu, Ying, Lu, Zhaojing, Yu, Shanshan

Keywords

none

MeSH Terms

Retina/metabolism
Photoreceptor Cells
Phosphotransferases (Alcohol Group Acceptor)/genetics*
Phosphotransferases (Alcohol Group Acceptor)/metabolism*
Cell Line
Animals
Retinal Cone Photoreceptor Cells/metabolism
Gene Knockout Techniques/methods
Mutation
Zebrafish Proteins/genetics*
Zebrafish Proteins/metabolism*
Phagocytosis/genetics
Humans
Receptor Protein-Tyrosine Kinases/metabolism
Retinitis Pigmentosa/metabolism
Retinal Pigment Epithelium/metabolism
Retinal Degeneration/genetics
Down-Regulation
Zebrafish/genetics
RNA, Messenger/metabolism

(all 20)

PubMed

28398482 Full text @ Hum. Mol. Genet.

Abstract

In humans, CERKL mutations cause widespread retinal degeneration: early dysfunction and loss of rod and cone photoreceptors in the outer retina and, progressively, death of cells in the inner retina. Despite intensive efforts, the function of CERKL remains obscure and studies in animal models have failed to clarify the disease mechanism of CERKL mutations. To address this gap in knowledge, we have generated a stable CERKL knockout zebrafish model by TALEN technology and a 7bp deletion in CERKL cDNA that caused the premature termination of CERKL. These CERKL-/- animals showed progressive degeneration of photoreceptor outer segments (OSs) and increased apoptosis of retinal cells, including those in the outer and inner retinal layers. Additionally, we confirmed by immunofluorescence and western-blot that rod degeneration in CERKL-/- zebrafish occurred earlier and was more significant than that in cone cells. Accumulations of shed OSs in the interphotoreceptor matrix were observed by transmission election microscopy (TEM). This suggested that CERKL may regulate the phagocytosis of OSs by the retinal pigment epithelium (RPE). We further found that the phagocytosis-associated protein MERTK was significantly reduced in CERKL-/- zebrafish. Additionally, in ARPE-19 cell lines, knockdown of CERKL also decreased the mRNA and protein level of MERTK, as well as the ox-POS phagocytosis. We conclude that CERKL deficiency in zebrafish may cause rod-cone dystrophy, but not cone-rod dystrophy, while interfering with the phagocytosis function of RPE associated with down-regulation of the expression of MERTK.

Genes / Markers

Figures

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Expression

Gene	Fish	Conditions	Stage	Anatomy	Assay	Figure
ctsd	cerkl^hzu3/hzu3	standard conditions	Days 30-44	eye	RTPCR	Fig. 7
ctsd	cerkl^hzu3/hzu3	standard conditions	Adult	eye	RTPCR	Fig. S5
ctsd	WT	standard conditions	Adult	eye	RTPCR	Fig. S5
ctsd	WT	standard conditions	Days 30-44	eye	RTPCR	Fig. 7
gas6	cerkl^hzu3/hzu3	standard conditions	Adult	eye	RTPCR	Fig. S5
gas6	cerkl^hzu3/hzu3	standard conditions	Days 30-44	eye	RTPCR	Fig. 7
gas6	WT	standard conditions	Adult	eye	RTPCR	Fig. S5
gas6	WT	standard conditions	Days 30-44	eye	RTPCR	Fig. 7
gnat1	cerkl^hzu3/hzu3	standard conditions	Adult	eye	RTPCR	Fig. S3
gnat1	WT	standard conditions	Adult	eye	RTPCR	Fig. S3

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Phenotype

Fish	Conditions	Stage	Phenotype	Figure
cerkl^hzu3/hzu3	standard conditions	Days 7-13	detection of light stimulus involved in visual perception decreased process quality, abnormal	Fig. 2
cerkl^hzu3/hzu3	standard conditions	Days 7-13	photoreceptor cell photoreceptor outer segment morphology, normal	Fig. S4
cerkl^hzu3/hzu3	standard conditions	Days 7-13	retina regulation of apoptotic cell clearance process quality, abnormal	Fig. S4
cerkl^hzu3/hzu3	standard conditions	Days 30-44	eye mertka expression decreased amount, abnormal	Fig. 7
cerkl^hzu3/hzu3	standard conditions	Days 30-44	eye Ab1-mertk labeling decreased amount, abnormal	Fig. 7
cerkl^hzu3/hzu3	standard conditions	Days 30-44	photoreceptor cell photoreceptor outer segment disorganized, abnormal	Fig. 3
cerkl^hzu3/hzu3	standard conditions	Days 30-44	retinal cone cell photoreceptor outer segment organization quality, normal	Fig. 5
cerkl^hzu3/hzu3	standard conditions	Days 30-44	retinal rod cell photoreceptor outer segment organization quality, normal	Fig. 5
cerkl^hzu3/hzu3	standard conditions	Days 45-89	eye ab1-gnat1 labeling decreased amount, abnormal	Fig. 6
cerkl^hzu3/hzu3	standard conditions	Days 45-89	eye ab1-grk1 labeling decreased amount, abnormal	Fig. 6

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
hzu3		Small Deletion	cerkl

Human Disease / Model

Human Disease	Fish	Conditions	Evidence
retinal degeneration			TAS

Sequence Targeting Reagents

Target	Reagent	Reagent Type
cerkl	TALEN1-cerkl	TALEN

Fish

Fish
cerkl^hzu3/hzu3
WT

Antibodies

Orthology

Engineered Foreign Genes

Mapping

Yu et al., 2017 ZDB-PUB-170412-3 PMID:28398482

CERKL gene knockout disturbs photoreceptor outer segment phagocytosis and causes rod-cone dystrophy in zebrafish

Yu et al., 2017

ZDB-PUB-170412-3
PMID:28398482