CRISPR/Cas9-mediated mutation of asparagine-linked glycosylation 13 transcript variant 1 causes epilepsy in mice

Abstract

Abstract Objective: The asparagine-linked glycosylation 13 homolog (Alg13) has been identified as causative for congenital disorders of glycosylation type I with epilepsy. The aim of this study was to determine whether mice carrying a mutated version of Alg13 could be used as a model for epileptic encephalopathies or congenital disorders of glycosylation type I. Methods: A model of epileptic encephalopathy was established in C57BL/6 mice by introducing mutations in Alg13 via the clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9) system. All surgical procedures were approved by the Institutional Animal Care and Use Committee of Shanghai Jiao Tong University (A2016084) on October 8, 2016. Results: Mice with 3 different mutations, Alg13 –54nt , Alg13 –5nt and Alg13 –4nt , all of which are located in Alg13 transcript variant 1, were created. The Alg13 –5nt mice exhibited spontaneous seizures similar to patients with Alg13 mutations, suggesting that they could be used as a model for epilepsy. Western blot analysis demonstrated that Alg13 –5nt mice had lower levels of Alg13 expression than wild-type mice. Video observations showed that two of the 17 Alg13 –5nt mice had stage 5 seizures involving jumping and falling, while 12 had stage 3 seizures with head nodding. Conclusion: The Alg13 mouse model provides an outstanding tool for studying epileptic encephalopathies and investigating different aspects of defects in glycosylation or other post-translational modification that cannot be assessed in patients or cell culture systems.