Sox6 expression distinguishes dorsally and ventrally biased dopamine neurons in the substantia nigra with distinctive properties and embryonic origins.

Dopamine (DA) neurons in the ventral tier of the substantia nigra pars compacta (SNc) degenerate prominently in Parkinson's disease, while those in the dorsal tier are relatively spared. Defining the molecular, functional, and developmental characteristics of each SNc tier is crucial to understand their distinct susceptibility. We demonstrate that Sox6 expression distinguishes ventrally and dorsally biased DA neuron populations in the SNc.

Expression and functional analysis of the Wnt/beta-catenin induced mir-135a-2 locus in embryonic forebrain development.

Background: Brain size and patterning are dependent on dosage-sensitive morphogen signaling pathways - yet how these pathways are calibrated remains enigmatic. Recent studies point to a new role for microRNAs in tempering the spatio-temporal range of morphogen functions during development. Here, we investigated the role of miR-135a, derived from the mir-135a-2 locus, in embryonic forebrain development.

The cortical hem regulates the size and patterning of neocortex.

The cortical hem, a source of Wingless-related (WNT) and bone morphogenetic protein (BMP) signaling in the dorsomedial telencephalon, is the embryonic organizer for the hippocampus. Whether the hem is a major regulator of cortical patterning outside the hippocampus has not been investigated. We examined regional organization across the entire cerebral cortex in mice genetically engineered to lack the hem.

An Lmx1b-miR135a2 regulatory circuit modulates Wnt1/Wnt signaling and determines the size of the midbrain dopaminergic progenitor pool.

MicroRNAs regulate gene expression in diverse physiological scenarios. Their role in the control of morphogen related signaling pathways has been less studied, particularly in the context of embryonic Central Nervous System (CNS) development. Here, we uncover a role for microRNAs in limiting the spatiotemporal range of morphogen expression and function.

Timing of cortical interneuron migration is influenced by the cortical hem.

Cerebral cortical γ-aminobutyric acid (GABA)ergic interneurons originate from the basal forebrain and migrate into the cortex in 2 phases. First, interneurons cross the boundary between the developing striatum and the cortex to migrate tangentially through the cortical primordium. Second, interneurons migrate radially to their correct neocortical layer position.