The E3 Ubiquitin Ligase UBE3B Regulates Synaptic Development and Cortical Network Activity

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Autism spectrum disorder (ASD) is a neurodevelopmental disorder linked to impaired communication and social interaction.
• Pathogenic mutations in UBE3B cause neurodevelopmental diseases, including ASD.
• The ubiquitin-proteasome system (UPS) is crucial for neurodevelopment, with UPS gene mutations implicated in ASD.

Purpose of the Study:

• To investigate the brain function of UBE3B and its role in neurodevelopmental abnormalities.
• To generate and evaluate a central nervous system-specific conditional Ube3b knockout (cKO) mouse model.

Main Methods:

• Generated a central nervous system-specific conditional Ube3b knockout (cKO) mouse model.
• Evaluated neurobehavioral phenotypes, including vocalization, social behavior, learning, memory, and motor skills.
• Assessed in vivo neuronal phenotypes, proteome, and ubiquitome of neural stem cells.

Main Results:

• Ube3b cKO mice displayed severe deficits in vocalization, social behavior, learning, memory, and motor skills.
• Neuronal analyses revealed defects in dendritic morphogenesis, reduced excitatory synapse density, and altered cortical circuit activity.
• Proteomic analysis identified 116 proteins with altered levels and ubiquitination in Ube3b-deficient neural stem cells, enriched for synaptic functions.

Conclusions:

• UBE3B plays a critical role in regulating social, cognitive, and motor functions.
• UBE3B is essential for neuronal morphogenesis and activity by modulating the synaptic proteome.
• Disruption of UBE3B function contributes to neurodevelopmental abnormalities relevant to ASD.