RT Journal Article
SR Electronic
T1 <em>Neurog1</em> and <em>Neurog2</em> Control Two Waves of Neuronal Differentiation in the Piriform Cortex
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 539
OP 553
DO 10.1523/JNEUROSCI.0614-13.2014
VO 34
IS 2
A1 Rajiv Dixit
A1 Grey Wilkinson
A1 Gonzalo I. Cancino
A1 Tarek Shaker
A1 Lata Adnani
A1 Saiqun Li
A1 Daniel Dennis
A1 Deborah Kurrasch
A1 Jennifer A. Chan
A1 Eric C. Olson
A1 David R. Kaplan
A1 Céline Zimmer
A1 Carol Schuurmans
YR 2014
UL http://www.jneurosci.org/content/34/2/539.abstract
AB The three-layered piriform cortex, an integral part of the olfactory system, processes odor information relayed by olfactory bulb mitral cells. Specifically, mitral cell axons form the lateral olfactory tract (LOT) by targeting lateral olfactory tract (lot) guidepost cells in the piriform cortex. While lot cells and other piriform cortical neurons share a pallial origin, the factors that specify their precise phenotypes are poorly understood. Here we show that in mouse, the proneural genes Neurog1 and Neurog2 are coexpressed in the ventral pallium, a progenitor pool that first gives rise to Cajal-Retzius (CR) cells, which populate layer I of all cortical domains, and later to layer II/III neurons of the piriform cortex. Using loss-of-function and gain-of-function approaches, we find that Neurog1 has a unique early role in reducing CR cell neurogenesis by tempering Neurog2's proneural activity. In addition, Neurog1 and Neurog2 have redundant functions in the ventral pallium, acting in two phases to first specify a CR cell fate and later to specify layer II/III piriform cortex neuronal identities. In the early phase, Neurog1 and Neurog2 are also required for lot cell differentiation, which we reveal are a subset of CR neurons, the loss of which prevents mitral cell axon innervation and LOT formation. Consequently, mutation of Trp73, a CR-specific cortical gene, results in lot cell and LOT axon displacement. Neurog1 and Neurog2 thus have unique and redundant functions in the piriform cortex, controlling the timing of differentiation of early-born CR/lot cells and specifying the identities of later-born layer II/III neurons.