Lhx2 Expression in Postmitotic Cortical Neurons Initiates Assembly of the Thalamocortical Somatosensory Circuit

Publication date: 24 January 2017
Source:Cell Reports, Volume 18, Issue 4
Author(s): Chia-Fang Wang, Hsiang-Wei Hsing, Zi-Hui Zhuang, Meng-Hsuan Wen, Wei-Jen Chang, Carlos G. Briz, Marta Nieto, Bai Chuang Shyu, Shen-Ju Chou
Cortical neurons must be specified and make the correct connections during development. Here, we examine a mechanism initiating neuronal circuit formation in the barrel cortex, a circuit comprising thalamocortical axons (TCAs) and layer 4 (L4) neurons. When Lhx2 is selectively deleted in postmitotic cortical neurons using conditional knockout (cKO) mice, L4 neurons in the barrel cortex are initially specified but fail to form cellular barrels or develop polarized dendrites. In Lhx2 cKO mice, TCAs from the thalamic ventral posterior nucleus reach the barrel cortex but fail to further arborize to form barrels. Several activity-regulated genes and genes involved in regulating barrel formation are downregulated in the Lhx2 cKO somatosensory cortex. Among them, Btbd3, an activity-regulated gene controlling dendritic development, is a direct downstream target of Lhx2. We find that Lhx2 confers neuronal competency for activity-dependent dendritic development in L4 neurons by inducing the expression of Btbd3.

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Teaser

Wang et al. find that the transcription factor Lhx2 functions in postmitotic cortical neurons to initiate barrel cortex formation. Lhx2 induces the expression of activity-regulated genes that enable layer 4 neurons in the somatosensory cortex to respond to thalamocortical inputs, develop dendritic asymmetry, and form cellular barrels.


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