Spinocerebellar ataxia type 1 (SCA1) is characterized by adult-onset cerebellar degeneration with attendant loss of motor coordination. Bulbar function is eventually impaired and patients typically die from an inability to clear the airway. We investigated whether motor neuron degeneration is at the root of bulbar dysfunction by studying SCA1 knock-in (Atxn1154Q/+ ) mice. Spinal cord and brains...

Larval motor neurons remodel during Drosophila neuro-muscular junction dismantling at metamorphosis. In this study, we describe the motor neuron retraction as opposed to degeneration based on the early disappearance of β-Spectrin and the continuing presence of Tubulin. By blocking cell dynamics with a dominant-negative form of Dynamin, we show that phagocytes have a key role in this process. Im...

genes that control motor neuron induction, subtype identity, and target specificity. Mice were mutagenized with ENU and outcrossed to an HB9-GFP transgenic reporter line that expresses GFP in spinal motor neurons and their axons. Litters were analyzed by fluorescence microscopy for recessive mutations that affect motor neuron induction and motor axon projection pattern. We have screened 137 F1 ...

genes that control motor neuron induction, subtype identity, and target specificity. Mice were mutagenized with ENU and outcrossed to an HB9-GFP transgenic reporter line that expresses GFP in spinal motor neurons and their axons. Litters were analyzed by fluorescence microscopy for recessive mutations that affect motor neuron induction and motor axon projection pattern. We have screened 137 F1 ...

Sonic hedgehog signaling controls the differentiation of motor neurons in the ventral neural tube, but the intervening steps are poorly understood. A differential screen of a cDNA library derived from a single Shh-induced motor neuron has identified a novel homeobox gene, MNR2, expressed by motor neuron progenitors and transiently by postmitotic motor neurons. The ectopic expression of MNR2 in ...

In the developing spinal cord, motor neurons acquire columnar subtype identities that can be recognized by distinct profiles of homeodomain transcription factor expression. The mechanisms that direct the differentiation of motor neuron columnar subtype from an apparently uniform group of motor neuron progenitors remain poorly defined. In the chick embryo, the Mnx class homeodomain protein MNR2 ...