Isl1 directly controls a cholinergic neuronal identity in the developing forebrain and spinal cord by forming cell...

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• Neuronal fate specification requires precise neurotransmitter characteristics.
• Coordinated gene regulation for neurotransmission is poorly understood in vertebrate development.

Purpose of the Study:

• Investigate gene regulatory networks specifying cholinergic neuronal fates in the spinal cord and forebrain.
• Elucidate the role of Isl1 in determining cholinergic neuronal identity.

Main Methods:

• Conditional inactivation of Isl1 in developing neurons.
• Genome-wide ChIP-seq analysis to identify gene targets.
• Assessment of cholinergic gene expression in vitro and in vivo.

Main Results:

• Loss of Isl1 drastically reduced cholinergic neurons in spinal cord and forebrain.
• Isl1 forms distinct Isl1-Lhx3 and Isl1-Lhx8 complexes.
• These complexes bind and upregulate key cholinergic pathway genes, including synthesizing enzymes and transporters.
• Isl1-Lhx8 complex expression induced cholinergic fate in stem cell-derived neurons.

Conclusions:

• A shared molecular mechanism involving Isl1 complexes determines cholinergic neuronal fate in the spinal cord and forebrain.
• Uncovered a gene regulatory mechanism essential for specific neurotransmitter identity in the vertebrate CNS.