Transcriptional Regulation of Cortical Interneuron Development

GABAergic interneurons (INs) constitute 20%–30% of the pallial (neocortical and hippocampal) neurons. They are the main source of cortical and hippocampal synaptic inhibitory signals. Distinct IN subtypes inhibit different cellular and subcellular components of pallial circuits. INs are generated from different subdomains of the embryonic basal ganglia (ganglionic eminences, GEs). Transcription factors (TFs) through regulatory elements (REs) that they bind are integral in programming gene expression in a temporally and spatially diverse manner. This then programs cell fate-commitment, differentiation, migration, and maturation to generate different IN subtypes. Of note, the prevailing molecular and genetic knowledge about IN development has been established by decades of studies in rodent and is hypothesized to reflect many of the processes common to mammals. Research on human and primate brain development will test this hypothesis and also offers the opportunity to identify species-specific variations. In this chapter, we focus on discoveries derived from mouse research. This chapter reviews the histology of the GEs, fate-mapping tools, TFs that control regional patterning of the GEs, TFs that regulate IN maturation, and REs that are involved in IN development.