The UBE3A gene encodes ubiquitin-protein ligase E3A, a critical enzyme in the ubiquitin-proteasome degradation system responsible for catalyzing substrate ubiquitination and regulating proteasomal clearance. This process is indispensable for maintaining proteostasis, particularly in neurons, where UBE3A governs synaptic plasticity, neural signaling, and neurodevelopment by modulating the levels of specific substrates. As an imprinted gene, UBE3A exhibits parent-of-origin-specific expression in brain neurons. The paternal allele is epigenetically silenced via cis-acting repression by a long noncoding antisense transcript (UBE3A-ATS) ^[1]. Consequently, only the maternal UBE3A allele is functionally active in neuronal populations. Loss of maternal UBE3A function disrupts ubiquitin-mediated proteolysis, leading to aberrant accumulation of neurodevelopmental regulators and subsequent dysregulation of synaptic maturation and circuit formation. These molecular deficits underlie the pathogenesis of Angelman syndrome (AS), a severe neurogenetic disorder. Patients with Angelman Syndrome commonly exhibit severe motor and intellectual developmental delays, ataxia, hypotonia, epilepsy, speech impairment, and distinctive facial features ^[2]. The huUBE3A mice are generated by replacing the mouse Ube3a genomic sequence from the ATG start codon to the TAA stop codon with the corresponding human UBE3A sequence. These mice can be used for studying the pathogenesis of Angelman syndrome (AS), developing related therapeutic approaches, and conducting preclinical research on UBE3A-targeted drugs.

Efcab7 is located on chromosome 4 of mice. SgRNA and ssDNA will be designed using Nuclease Technology; Efcab7 conditional knockout mice will be obtained by high-throughput electroporation of fertilized eggs. After sexual maturity, sperm will be collected for cryopreservation.