Thomas M. Jessell
Election Year: 2002
Primary Section: 24, Cellular and Molecular Neuroscience
Secondary Section: 28, Systems Neuroscience
Membership Type: Foreign Associate
My research has focused on molecular mechanisms that control the assembly of neuronal connections during the development of the vertebrate central nervous system, using circuits that subserve sensory-motor function in the spinal cord as a model system. A combination of cellular and genetic assays has shown how spinal cord progenitor cells acquire their early positional identity and how they respond to inductive signals with the generation of specific neuronal subtypes. These studies have revealed that some secreted inductive factors, notably Sonic Hedgehog, function as gradient morphogens, imposing precise spatial patterns of expression of transcription factors that determine motor neuron and interneuron identity. In addition, my work has shown that hierarchical sets of transcription factors expressed by subsets of post-mitotic neurons orchestrate two of the later steps in circuit assembly (axonal guidance and synaptic connectivity) by regulating the expression of downstream genes that encode neuronal surface receptors and adhesion proteins.