A sclerocornea-associated RAD21 variant induces corneal stroma disorganization

• Published in: Experimental eye research 2019-08, Vol.185, p.107687-107687, Article 107687
• Main Authors: Zhang, Bi Ning, Wong, Thomas Chi Bun, Yip, Yolanda Wong Ying, Liu, Ziran, Wang, Chengdong, Wong, Janice Siu Chong, He, Jing Na, Chan, Tommy Chung Yan, Jhanji, Vishal, Pang, Chi Pui, Zhao, Hui, Chu, Wai Kit
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis Regulatory Proteins - genetics; Cell Cycle Proteins - genetics; Collagen - metabolism; Cornea - abnormalities; Cornea - embryology; Cornea - ultrastructure; Corneal Diseases - embryology; Corneal Diseases - genetics; Corneal stroma; Corneal Stroma - pathology; Corneal Stroma - ultrastructure; Gene Expression Regulation, Developmental - physiology; Genetic Variation; In Situ Hybridization; Microscopy, Electron, Transmission; Mutagenesis, Site-Directed; Peripheral sclerocornea; Plasmids; RAD21; RNA, Messenger - genetics; Stroma attracting center; Xenopus laevis - embryology; Xenopus Proteins - genetics
• ISSN: 0014-4835; 1096-0007
• DOI: 10.1016/j.exer.2019.06.001

Sclerocornea is a cornea opacification disorder. Disorganized corneal stroma fibrils are observed in patients’ cornea. Previously we identified a RAD21C1348T variant that is associated with a peripheral sclerocornea pedigree. To explore whether this RAD21 variant can induce sclerocornea-related phenotype, and to investigate the possible mechanisms of such phenotype, the orthologous rad21 wild-type and variant mRNAs were injected into Xenopus laevis embryos and the developed eyes were subjected for histological examination. Transmission electron microscopy was applied for corneal stroma organization check. rad21 is highly expressed in the eye region during X. laevis development. Disrupted eye development was observed in the rad21 variant injected embryos. Disorganized corneal stroma and decreased diameters of collagen fibrils were observed in the rad21 variant injected X. laevis eyes. These eye defects can be rescued by overexpression of the wild-type rad21. Histological examination found stroma attracting center, a key structure in X. laevis corneal development, was impaired in rad21 variant injected embryos. Our results suggest a key role of RAD21 during corneal development. Our data indicates the RAD21R450C variant contributes to peripheral sclerocornea by disturbing collagen fibril organization in the corneal stroma. •Sclerocornea-associated rad21 variant disrupted eye development.•rad21 variant led to disorganized corneal stroma of collagen fibrils.•Stroma attracting center was impaired in rad21 variant injected frog embryos.