Andrew D. Chisholm

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Synapses display a stereotyped ultrastructural organization, commonly containing a single electron-dense presynaptic density surrounded by a cluster of synaptic vesicles. The mechanism controlling subsynaptic proportion is not understood. Loss of function in the C. elegans rpm-1 gene, a putative RING finger/E3 ubiquitin ligase, causes disorganized(More)
Growth cone guidance and synaptic plasticity involve dynamic local changes in proteins at axons and dendrites. The Dual-Leucine zipper Kinase MAPKKK (DLK) has been previously implicated in synaptogenesis and axon outgrowth in C. elegans and other animals. Here we show that in C. elegans DLK-1 regulates not only proper synapse formation and axon morphology(More)
Mutations in the C. elegans vab-1 gene disrupt the coordinated movements of cells during two periods of embryogenesis. vab-1 mutants are defective in the movement of neuroblasts during closure of the ventral gastrulation cleft and in the movements of epidermal cells during ventral enclosure of the embryo by the epidermis. We show that vab-1 encodes a(More)
Cells in the mid-body region of the nematode C. elegans develop differently from their anterior or posterior homologs. The gene lin-39 is required for mid-body region-specific development. In lin-39 mutants, mid-body cells express fates characteristic of more anterior or posterior homologs, and the migration of a neuroblast through the mid-body is(More)
The C. elegans defecation cycle is characterized by the contraction of three distinct sets of muscles every 50 s. Our data indicate that this cycle is regulated by periodic calcium release mediated by the inositol trisphosphate receptor (IP3 receptor). Mutations in the IP3 receptor slow down or eliminate the cycle, while overexpression speeds up the cycle.(More)
The morphogenesis of the C. elegans embryo is largely controlled by the development of the epidermis, also known as the hypodermis, a single epithelial layer that surrounds the animal. Morphogenesis of the epidermis involves cell-cell interactions with internal tissues, such as the developing nervous system and musculature. Genetic analysis of mutants with(More)
Axons of adult Caenorhabditis elegans neurons undergo robust regenerative growth after laser axotomy. Here we show that axotomy of PLM sensory neurons triggers axonal calcium waves whose amplitude correlates with the extent of regeneration. Genetic elevation of Ca(2+) or cAMP accelerates formation of a growth cone from the injured axon. Elevated Ca(2+) or(More)
We previously reported functional regeneration of Caenorhabditis elegans motor neurons after femtosecond laser axotomy. We report here that multiple neuronal types can regrow after laser axotomy using a variety of lasers. The precise pattern of regrowth varies with cell type, stage of animal, and position of axotomy. Mechanosensory axons cut in late larval(More)
The Eph receptor VAB-1 is required in neurons for epidermal morphogenesis during C. elegans embryogenesis. Two models were proposed for the non-autonomous role of VAB-1: neuronal VAB-1 might signal directly to epidermis, or VAB-1 signaling between neurons might be required for epidermal development. We show that the ephrin VAB-2 (also known as EFN-1) is a(More)
Laminins are heterotrimeric (alpha/beta/gamma) glycoproteins that form a major polymer within basement membranes. Different alpha, beta and gamma subunits can assemble into various laminin isoforms that have different, but often overlapping, distributions and functions. In this study, we examine the contributions of the laminin alpha subunits to the(More)