TSC tunes progenitor balance and upper-layer neuron generation in neocortex.

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• Proper formation of cerebral cortex circuits depends on precise generation of upper-layer neurons.
• Radial progenitors generate intermediate progenitors (IPs), which expand the cortical neuronal population.
• The molecular mechanisms controlling progenitor balance and neuronal diversity are not fully understood.

Purpose of the Study:

• To investigate the role of tuberous sclerosis complex (TSC) proteins in sculpting progenitor balance and upper-layer neuron generation.
• To understand how TSC protein expression influences radial unit organization and cortical development.

Main Methods:

• Developmental deletion of TSC proteins in a model system.
• Analysis of radial progenitor and intermediate progenitor (IP) balance.
• Investigating human-specific enhancers modulating TSC protein expression.
• Examining evolutionary changes in TSC protein expression.

Main Results:

• TSC proteins are crucial for maintaining radial progenitor-intermediate progenitor (IP) balance and radial unit organization.
• Deletion of TSC proteins leads to increased upper-layer neuron generation and altered cortical connectivity.
• Human-specific enhancers affecting TSC expression impact progenitor balance and upper-layer neuron output.
• Evolutionary downregulation of TSC proteins correlates with expanded upper-layer neuron generation in humans.

Conclusions:

• TSC proteins play a key role in regulating cortical progenitor balance and neuronal output.
• Modulation of TSC protein expression is a critical factor in the evolution of human brain complexity.
• Understanding TSC protein function provides insights into the development of higher-order brain functions.