Opposing regulation of Sox2 by cell-cycle effectors E2f3a and E2f3b in neural stem cells

Area of Science:

• Neuroscience
• Developmental Biology
• Stem Cell Biology

Background:

• Cell-cycle control and cell-fate decisions in proliferating stem cells are poorly understood.
• E2f3 isoforms, in conjunction with the retinoblastoma protein (pRb), regulate cell-cycle progression.

Purpose of the Study:

• To investigate the role of E2f3 isoforms in coordinating cell-cycle control and cell-fate decisions during neurogenesis.
• To elucidate the mechanism by which E2f3 isoforms regulate Sox2 gene expression and its impact on neural precursor cells.

Main Methods:

• Analysis of E2f3 isoform function in developmental and adult neurogenesis models.
• Investigation of Sox2 gene regulation by E2f3 isoforms.
• Assessment of neural precursor cell maintenance and differentiation.
• Evaluation of hippocampal neurogenesis and memory formation in E2f3 mutant mice.

Main Results:

• Loss of either E2f3 isoform disrupts Sox2 gene regulation and the balance between neural precursor maintenance and differentiation in the developing cortex.
• Both E2f3 isoforms target the Sox2 locus to maintain baseline Sox2 expression but antagonistically regulate Sox2 levels to instruct cell fate.
• E2f3-mediated regulation of Sox2 and neural precursor cell fate is conserved in the adult brain, with E2f3a loss impairing hippocampal neurogenesis and memory.

Conclusions:

• E2f3 isoforms differentially regulate Sox2 dosage in neural precursors, providing a mechanism for coordinating cell-cycle control and cell-fate decisions.
• This regulatory mechanism is critical for both developmental and adult neurogenesis and has implications for understanding diverse stem cell populations.