Selective cortical layering abnormalities and behavioral deficits in cortex-specific Pax6 knock-out mice

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• Pax6 is vital for vertebrate neocortical neurogenesis.
• Previous studies were limited by the lethality of Pax6 mutants.

Purpose of the Study:

• To investigate the role of Pax6 in cortical development and cognitive function.
• To generate viable Pax6 conditional mutants for detailed analysis.

Main Methods:

• Generated conditional Pax6 mutants using Emx1-Cre and hGFAP-Cre lines for timed inactivation.
• Analyzed cortical layer formation, progenitor behavior, and oligodendrocyte production.
• Assessed sensorimotor integration and memory recall in mutant mice.

Main Results:

• Early Pax6 inactivation (Emx1-Cre) caused premature progenitor cell cycle exit, reduced upper layer neurons, and increased oligodendrocytes.
• Late Pax6 inactivation (hGFAP-Cre) did not impact late-born neurons, suggesting progenitor pool depletion is key.
• Pax6 mutants showed deficits in sensorimotor integration and both short-term and long-term memory.

Conclusions:

• Pax6 is essential for maintaining the progenitor pool required for late neurogenesis and upper layer formation.
• Pax6 deficiency leads to significant cognitive and memory impairments.
• These findings provide a valuable model for understanding aniridia-related neurodevelopmental abnormalities.