Azim E, Shnider SJ, Cederquist GY, Sohur US, Macklis JD. 2009. Lmo4 and Clim1 progressively delineate cortical projection neuron subtypes during development. Cerebral cortex (New York, N.Y. : 1991). 19 Suppl 1(Suppl 1):i62-9. Pubmed: 19366868 DOI:10.1093/cercor/bhp030


Molecular controls over the development of the exceptional neuronal subtype diversity of the cerebral cortex are now beginning to be identified. The initial subtype fate decision early in the life of a neuron, and the malleability of this fate when the balance of key postmitotic signals is modified, reveals not only that a neuron is deterministically set on a general developmental path at its birth, but also that this program must be precisely executed during postmitotic differentiation. Here, we show that callosal projection neurons (CPN) and subcerebral projection neurons (subcerebral PN) in layer V of the neocortex share aspects of molecular identity after their birth that are progressively resolved during differentiation. The LIM-homeodomain-related genes Lmo4 and Clim1 are initially expressed by both CPN and subcerebral PN in layer V, and only during mid to late differentiation does expression of Lmo4 and Clim1 become largely segregated into distinct neuronal subtypes. This progressive postmitotic resolution of molecular identity reveals similarities and possibly shared evolutionary origin between layer V CPN and subcerebral PN, and provides insight into how and when these neuronal subtypes achieve their distinct identities during cortical development.

Related Faculty

Photo of Jeffrey D. Macklis

Jeffrey Macklis investigates molecular controls and mechanisms over neuron subtype specification, development, diversity, axon guidance-circuit formation, and pathology in the cerebral cortex. His lab seeks to apply developmental controls toward brain and spinal cord regeneration and directed differentiation for in vitro mechanistic modeling using human assembloids.

Search Menu