The neuron-specific chromatin regulatory subunit BAF53b is necessary for synaptic plasticity and memory

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Polymorphic Brg1-associated factor (BAF) complexes, also known as mammalian SWI/SNF chromatin remodeling complexes, are implicated in human intellectual disabilities.
• The specific mechanisms by which BAF complex mutations lead to cognitive impairment remain largely unknown.
• Postmitotic neurons utilize a neuron-specific BAF assembly (nBAF) containing the BAF53b subunit.

Purpose of the Study:

• To investigate the role of the BAF53b subunit in cognitive function and synaptic plasticity.
• To explore the potential for rescuing cognitive deficits by restoring BAF53b expression in adult neurons.

Main Methods:

• Utilized mouse models with selective genetic manipulations of the BAF53b subunit.
• Assessed long-term memory and hippocampal synaptic plasticity in mutant mice.
• Investigated the rescue of memory impairments by reintroducing BAF53b in the adult hippocampus.
• Analyzed gene expression alterations and their impact on postsynaptic components.

Main Results:

• Mice lacking functional BAF53b exhibited severe deficits in long-term memory and hippocampal synaptic plasticity.
• Reintroducing BAF53b in the adult hippocampus successfully rescued memory impairments.
• Observed alterations in gene expression in mutant mice, leading to abnormal postsynaptic structure and function.
• Deficits in synaptic plasticity were linked to these gene expression changes.

Conclusions:

• BAF53b plays a critical role in maintaining cognitive function and synaptic plasticity beyond neuronal development.
• Dominant mutations in BAF complex subunits contribute to human intellectual and cognitive disorders through altered gene expression and synaptic function.
• These findings offer new insights into the molecular basis of cognitive disorders linked to BAF complexes.