Expression of transcription factors divides retinal ganglion cells into distinct classes.

Retinal ganglion cells (RGCs) are tasked with transmitting all light information from the eye to the retinal recipient areas of the brain. RGCs can be classified into many different types by morphology, gene expression, axonal projections, and functional responses to different light stimuli. Ultimately, these classification systems should be unified into an all-encompassing taxonomy.

Ephrin-As are required for the topographic mapping but not laminar choice of physiologically distinct RGC types.

In the retinocollicular projection, the axons from functionally distinct retinal ganglion cell (RGC) types form synapses in a stereotypical manner along the superficial to deep axis of the superior colliculus (SC). Each lamina contains an orderly topographic map of the visual scene but different laminae receive inputs from distinct sets of RGCs, and inputs to each lamina are aligned with the others to integrate parallel streams of visual information. To determine the relationship between laminar organization and topography of physiologically defined RGC types, we used genetic and anatomical axon tracing techniques in wild type and ephrin-A mutant mice.

How postdocs benefit from building a union.

Members of UAW 5810—the union for postdoctoral researchers at the University of California—describe how their union has led to improved terms and conditions for postdocs.

Tbr2 is required to generate a neural circuit mediating the pupillary light reflex.

There are ∼20 types of retinal ganglion cells (RGCs) in mice, each of which has distinct molecular, morphological, and physiological characteristics. Each RGC type sends axon projections to specific brain areas that execute light-dependent behaviors. Here, we show that the T-box transcription factor Tbr2 is required for the development of several RGC types that participate in non-image-forming circuits.

Dendritic and axonal targeting patterns of a genetically-specified class of retinal ganglion cells that participate in image-forming circuits.

Background: There are numerous functional types of retinal ganglion cells (RGCs), each participating in circuits that encode a specific aspect of the visual scene. This functional specificity is derived from distinct RGC morphologies and selective synapse formation with other retinal cell types; yet, how these properties are established during development remains unclear. Islet2 (Isl2) is a LIM-homeodomain transcription factor expressed in the developing retina, including approximately 40% of all RGCs, and has previously been implicated in the subtype specification of spinal motor neurons.

Competition is a driving force in topographic mapping.

Topographic maps are the primary means of relaying spatial information in the brain. Understanding the mechanisms by which they form has been a goal of experimental and theoretical neuroscientists for decades. The projection of the retina to the superior colliculus (SC)/tectum has been an important model used to show that graded molecular cues and patterned retinal activity are required for topographic map formation.

Genetic screen identifies serpin5 as a regulator of the toll pathway and CHMP2B toxicity associated with frontotemporal dementia.

Frontotemporal dementia (FTD) is the most common form of dementia before 60 years of age. Rare pathogenic mutations in CHMP2B, which encodes a component of the endosomal sorting complex required for transport (ESCRT-III), are associated with FTD linked to chromosome 3 (FTD3). Animal models of FTD3 have not yet been reported, and what signaling pathways are misregulated by mutant CHMP2B in vivo is unknown.

The coiled-coil protein shrub controls neuronal morphogenesis in Drosophila.

The diversity of neuronal cells, especially in the size and shape of their dendritic and axonal arborizations, is a striking feature of the mature nervous system. Dendritic branching is a complex process, and the underlying signaling mechanisms remain to be further defined at the mechanistic level. Here we report the identification of shrub mutations that increased dendritic branching.

Lipid- and protein-mediated multimerization of PSD-95: implications for receptor clustering and assembly of synaptic protein networks.

Postsynaptic density protein 95 (PSD-95/SAP-90) is a palmitoylated membrane-associated guanylate kinase that oligomerizes and clusters ion channels and associated signaling machinery at excitatory synapses in brain. However, the mechanism for PSD-95 oligomerization and its relationship to ion channel clustering remain uncertain. Here, we find that multimerization of PSD-95 is determined by only its first 13 amino acids, which also have a remarkable capacity to oligomerize heterologous proteins.

Genetic manipulation of single neurons in vivo reveals specific roles of flamingo in neuronal morphogenesis.

To study the roles of intracellular factors in neuronal morphogenesis, we used the mosaic analysis with a repressible cell marker (MARCM) technique to visualize identifiable single multiple dendritic (MD) neurons in living Drosophila larvae. We found that individual neurons in the peripheral nervous system (PNS) developed clear morphological polarity and diverse dendritic branching patterns in larval stages. Each MD neuron in the same dorsal cluster developed a unique dendritic field, suggesting that they have specific physiological functions.

Synaptic strength regulated by palmitate cycling on PSD-95.

Dynamic regulation of AMPA-type glutamate receptors represents a primary mechanism for controlling synaptic strength, though mechanisms for this process are poorly understood. The palmitoylated postsynaptic density protein, PSD-95, regulates synaptic plasticity and associates with the AMPA receptor trafficking protein, stargazin. Here, we identify palmitate cycling on PSD-95 at the synapse and find that palmitate turnover on PSD-95 is regulated by glutamate receptor activity.