Deletion of the transmembrane protein Prom1b in zebrafish disrupts outer-segment morphogenesis and causes photoreceptor degeneration

Zhaojing Lu, Xuebin Hu, James Reilly, Danna Jia, Fei Liu, Shanshan Yu, Xiliang Liu, Shanglun Xie, Zhen Qu, Yayun Qin, Yuwen Huang, Yuexia Lv, Jingzhen Li, Pan Gao, Fulton Wong, Xinhua Shu, Zhaohui Tang, Mugen Liu

Research output: Contribution to journalArticle

Abstract

Mutations in human prominin 1 (PROM1), encoding a transmembrane glycoprotein localized mainly to plasma membrane protrusions, have been reported to cause retinitis pigmentosa, macular degeneration and cone-rod dystrophy. Although the structural role of PROM1 in outer-segment (OS) morphogenesis has been demonstrated in Prom1-knockout mouse, the mechanisms underlying these complex disease phenotypes remain unclear. Here we utilized a zebrafish model to further investigate PROM1's role in the retina. The Prom1 orthologs in zebrafish include prom1a and prom1b, and our results showed that prom1b, rather than prom1a, plays an important role in zebrafish photoreceptors. Loss of prom1b disrupted OS morphogenesis, with rods and cones exhibiting differences in impairment: cones degenerated at an early age, whereas rods remained viable, but with an abnormal OS, even at 9 months post-fertilization. Immunofluorescence experiments with WT zebrafish revealed that Prph2, an ortholog of the human transmembrane protein peripherin 2 and also associated with OS formation, is localized to the edge of OS and is more highly expressed in the cone OS than in the rod OS. Moreover, we found that Prom1b deletion causes mislocalization of Prph2 and disrupts its oligomerization. We conclude that the variation in Prph2 levels between cones and rods was one of the reasons for the different PROM1 mutation-induced phenotypes of these retinal structures. These findings expand our understanding of the phenotypes caused by PROM1 mutations and provide critical insights into its function.
Original languageEnglish
Pages (from-to)13953-13963
Number of pages11
JournalJournal of Biological Chemistry
Volume294
Issue number38
Early online date30 Jul 2019
DOIs
Publication statusPublished - 20 Sep 2019

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Keywords

  • retinal degeneration, prominin 1 (PROM1), photoreceptor, morphogenesis, peripherin 2 (PRPH2), eye disease, Danio rerio

Cite this

Lu, Z., Hu, X., Reilly, J., Jia, D., Liu, F., Yu, S., Liu, X., Xie, S., Qu, Z., Qin, Y., Huang, Y., Lv, Y., Li, J., Gao, P., Wong, F., Shu, X., Tang, Z., & Liu, M. (2019). Deletion of the transmembrane protein Prom1b in zebrafish disrupts outer-segment morphogenesis and causes photoreceptor degeneration. Journal of Biological Chemistry, 294(38), 13953-13963. https://doi.org/10.1074/jbc.RA119.008618