Tole, S., Remedios, R., Saha, B. & Stoykova, A. Selective requirement of Pax6, but not Emx2, in the specification and development of several nuclei of the amygdaloid complex. J. Neurosci. 25, 2753-2760

Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.34). 04/2005; 25(10):2753-60. DOI: 10.1523/JNEUROSCI.3014-04.2005
Source: PubMed


The amygdaloid complex is a group of nuclei that are thought to originate from multiple sites of the dorsal and ventral telencephalic neuroepithelium. The mechanisms that regulate their development are essentially unknown. We studied the role of Pax6 and Emx2, two transcription factors that regulate regional specification and growth of the telencephalon, in the morphogenesis of the amygdaloid complex. We used a set of specific marker genes that identify distinct amygdaloid nuclei to analyze Pax6/Small eye and Emx2 knock-out mutant mouse brains. We found that there is a selective requirement for Pax6, but not Emx2, in the formation a subset of nuclei within the amygdaloid complex. Specifically, structures that were not previously considered to be developmentally linked, the nucleus of the lateral olfactory tract and the lateral, basolateral, and basomedial nuclei, all appear to have a common requirement for Pax6. Together, our findings provide new insights into the origins and mechanisms underlying the development of the amygdaloid complex.

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    • "In neocortical development, Emx2, Pax6 and FGFs act in counterbalance . Pax6 deficiency results in an areal expansion of visual cortex, a reduction of frontal areas, and dysgenesis of limbic structures (Stoykova et al., 2000; Tole et al., 2005). On the other hand, Emx2 deficiency produces an expansion of frontal regions and a reduction of occipital regions (visual cortex; Bishop et al., 2000). "
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    • "In mouse embryos, the amygdalar derivatives of the ventral pallium are characterized by expression of Tbr1, Lhx2, and Lhx9 (Puelles et al., 2000; Medina et al., 2004; Tole et al., 2005; Garc ıa-L opez et al., 2008). These include part of the basal amygdalar complex, and the anterior and posteromedial cortical amygdalar areas. "
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    • "The analysis of VP and CR cell specification in these mutants would shed new light into the mechanisms of areal patterning gene functions. For example, it is known that Pax6 plays a crucial role in VP specification (Assimacopoulos et al., 2003; Tole et al., 2005). "
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