Outside-in temporal specification of thalamic nucleogenesis.

<p>(<b>A</b>) A schematic of the TH in the caudal diencephalon of the mouse embryo. In the sagittal schematic (left two panels), the embryo is facing left. The thalamus is bordered by the pretectum caudally, the habenula dorsally, the basal plate ventrally, and by the ZLI rostrally. The three dashed lines represent the planes of sections shown in the frontal schematic (right two panels). In this study, we used Cre drivers of 3 genes, <i>Gli1</i>, <i>Olig3</i>, and <i>Neurog1</i>. Within the color-labeled regions of the diencephalon, <i>Gli1</i> is expressed in pTH-C (rostro-ventral region near the pTH-R domain, shown in darker green) and the prethalamus (light blue) [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2005211#pbio.2005211.ref006" target="_blank">6</a>]. <i>Olig3</i> is expressed in pTH-C (green) and pTH-R (pink) domains of the thalamus as well as in the ZLI (dark blue) [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2005211#pbio.2005211.ref003" target="_blank">3</a>]. <i>Neurog1</i> is expressed in the habenula (yellow), pTH-C (green), and ZLI (dark blue) [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2005211#pbio.2005211.ref003" target="_blank">3</a>]. (<b>B</b>) Frontal sections of the forebrain showing EdU birthdating in the neonatal mouse thalamus with EdU injections at E10.5, E11.5, E12.5, E13.5, or E14.5. Three representative levels (dorsal, middle, and ventral) are shown for each stage of EdU injection. In all three levels, there is a general trend in which neurons of laterally located nuclei are born before neurons of more medially located nuclei, demonstrating the outside-in pattern of neurogenesis. Scale bar: 500 μm. 3V, third ventricle; Cx, cortex; EdU, ethynyldeoxyuridine; HB, habenula; Hyp, hypothalamus; LV, lateral ventricle; M, midbrain; PT, pretectum; PTH, prethalamus; pTH-C, caudal thalamic progenitor domain; pTH-R, rostral thalamic progenitor domain; RP, roof plate; TH, thalamus; Tel, telencephalon; ZLI, zona limitans intrathalamica.