A brain atlas for the camouflaging dwarf cuttlefish, Sepia bandensis.

The coleoid cephalopods (cuttlefish, octopus, and squid) are a group of soft-bodied marine mollusks that exhibit an array of interesting biological phenomena, including dynamic camouflage, complex social behaviors, prehensile regenerating arms, and large brains capable of learning, memory, and problem-solving. The dwarf cuttlefish, Sepia bandensis, is a promising model cephalopod species due to its small size, substantial egg production, short generation time, and dynamic social and camouflage behaviors. Cuttlefish dynamically camouflage to their surroundings by changing the color, pattern, and texture of their skin.

ALS-associated mutant FUS induces selective motor neuron degeneration through toxic gain of function.

Mutations in FUS cause amyotrophic lateral sclerosis (ALS), including some of the most aggressive, juvenile-onset forms of the disease. FUS loss-of-function and toxic gain-of-function mechanisms have been proposed to explain how mutant FUS leads to motor neuron degeneration, but neither has been firmly established in the pathogenesis of ALS. Here we characterize a series of transgenic FUS mouse lines that manifest progressive, mutant-dependent motor neuron degeneration preceded by early, structural and functional abnormalities at the neuromuscular junction.

Optimization of protein production in mammalian cells with a coexpressed fluorescent marker.

The expression of mammalian proteins in sufficient abundance and quality for structural studies often presents formidable challenges. Many express poorly in bacterial systems, whereas it can be time consuming and expensive to produce them from cells of higher organisms. Here we describe a procedure for the direct selection of stable mammalian cell lines that express proteins of interest in high yield.

Visualizing sexual dimorphism in the brain.

Sexually dimorphic behaviors are likely to involve neural pathways that express the androgen receptor (AR). We have genetically modified the AR locus to visualize dimorphisms in neuronal populations that express AR. Analysis of AR-positive neurons reveals both known dimorphisms in the preoptic area of the hypothalamus and the bed nucleus of the stria terminalis as well as novel dimorphic islands in the basal forebrain with a clarity unencumbered by the vast population of AR-negative neurons.

Gene switching and the stability of odorant receptor gene choice.

Individual olfactory sensory neurons express only a single odorant receptor from a large family of genes, and this singularity is an essential feature in models of olfactory perception. We have devised a genetic strategy to examine the stability of receptor choice. We observe that immature olfactory sensory neurons that express a given odorant receptor can switch receptor expression, albeit at low frequency.

Axonal ephrin-As and odorant receptors: coordinate determination of the olfactory sensory map.

Olfactory sensory neurons expressing a given odorant receptor (OR) project with precision to specific glomeruli in the olfactory bulb, generating a topographic map. In this study, we demonstrate that neurons expressing different ORs express different levels of ephrin-A protein on their axons. Moreover, alterations in the level of ephrin-A alter the glomerular map.