PUBLICATION
TMEM216 Deletion Causes Mislocalization of Cone Opsin and Rhodopsin and Photoreceptor Degeneration in Zebrafish
- Authors
- Liu, Y., Cao, S., Yu, M., Hu, H.
- ID
- ZDB-PUB-200721-5
- Date
- 2020
- Source
- Investigative ophthalmology & visual science 61: 24 (Journal)
- Registered Authors
- Keywords
- none
- MeSH Terms
-
- Animals
- Cone Opsins/metabolism*
- Gene Knockout Techniques
- Humans
- Membrane Proteins*/genetics
- Membrane Proteins*/metabolism
- Mutation
- Photoreceptor Cells/physiology*
- Retinal Degeneration/genetics
- Rhodopsin/metabolism*
- Zebrafish
- Zebrafish Proteins/genetics*
- PubMed
- 32687549 Full text @ Invest. Ophthalmol. Vis. Sci.
Citation
Liu, Y., Cao, S., Yu, M., Hu, H. (2020) TMEM216 Deletion Causes Mislocalization of Cone Opsin and Rhodopsin and Photoreceptor Degeneration in Zebrafish. Investigative ophthalmology & visual science. 61:24.
Abstract
Purpose Mutations in TMEM216, a ciliary transition zone tetraspan transmembrane protein, are linked to Joubert syndrome and Meckel syndrome. Photoreceptor degeneration is a prominent phenotype in Joubert syndrome. How TMEM216 contributes to photoreceptor health is poorly understood.
Methods We have generated tmem216 knockout zebrafish by CRISPR genome editing. The impact of TMEM216 deletion on photoreceptors was evaluated by immunofluorescence staining and electron microscopy.
Results Homozygous tmem216 knockout zebrafish died before 21 days after fertilization. Their retina exhibited reduced immunoreactivity to rod photoreceptor outer segment marker 4D2 and cone photoreceptor outer segment marker G protein subunit α transducin 2 (GNAT2). Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) revealed an increase in TUNEL-positive nuclei in the knockout retina, indicating photoreceptor degeneration. The tmem216 mutation resulted in shortened photoreceptor ciliary axoneme, as revealed by acetylated α-tubulin immunostaining. Photoreceptors in knockout zebrafish exhibited mislocalization of outer segment proteins such as rhodopsin, GNAT2, and red opsin to the inner segment and cell bodies. Additionally, electron microscopy revealed that the mutant photoreceptors elaborated outer segment with abnormal disc morphology such as shortened discs and vesicles/vacuoles within the outer segment.
Conclusion Our results indicate that TMEM216 is essential for normal genesis of outer segment disc structures, transport of outer segment materials, and survival of photoreceptors in zebrafish. These tmem216 knockout zebrafish will be useful in studying how transition zone proteins regulate photoreceptor outer segment formation and maintenance.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping