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[
Curr Top Membr,
1999]
The DNA sequence data produced by the Caenorhabditis elegans genome sequencing project has revealed a large extended family of potassium channels, the outlines of which are conserved with vertebrates. This initial peek into the nearly complete library of potassium channels from a single 'simple' organism has revealed a number and complexity of potassium channel types that surpassed expectations. The vast majority of potassium channel types revealed by expressed sequence tags (EST) sequencing projects from many vertebrate and invertebrate animals fit within the outlines of families present in C. elegans. Thus, the broad picture of potassium channel families in C. elegans may represent family relationships conserved among most vertebrate and invertebrate animals. This conservation implies that the electrical lives of cell from most metazoans have similar requirements and are similarly diverse. Furthermore, the fact that the structures and possible biophysical properties of many distinct potassium channel types are conserved implies that specific functional roles of potassium channels may be conserved, as well. Studies now underway to reveal the tissue channels in C. elegans could reveal such conserved roles. These studies may be a guide to similar studies in higher
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[
WormBook,
2005]
C. elegans has emerged as a powerful genetic model organism in which to study synaptic function. Most synaptic proteins in the C. elegans genome are highly conserved and mutants can be readily generated by forward and reverse genetics. Most C. elegans synaptic protein mutants are viable affording an opportunity to study the functional consequences in vivo. Recent advances in electrophysiological approaches permit functional analysis of mutant synapses in situ. This has contributed to an already powerful arsenal of techniques available to study synaptic function in C. elegans. This review highlights C. elegans mutants affecting specific stages of the synaptic vesicle cycle, with emphasis on studies conducted at the neuromuscular junction.
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[
WormBook,
2005]
C. elegans presents a low level of molecular diversity, which may be explained by its selfing mode of reproduction. Recent work on the genetic structure of natural populations of C. elegans indeed suggests a low level of outcrossing, and little geographic differentiation because of migration. The level and pattern of molecular diversity among wild isolates of C. elegans are compared with those found after accumulation of spontaneous mutations in the laboratory. The last part of the chapter reviews phenotypic differences among wild isolates of C. elegans.
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[
Methods Cell Biol,
1995]
Sequence analysis of cosmids from C. elegans and other organisms currently is best done using the random or "shotgun" strategy (Wilson et al., 1994). After shearing by sonication, DNA is used to prepare M13 subclone libraries which provide good coverage and high-quality sequence data. The subclones are assembled and the data edited using software tools developed especially for C. elegans genomic sequencing. These same tools facilitate much of the subsequent work to complete both strands of the sequence and resolve any remaining ambiguities. Analysis of the finished sequence is then accomplished using several additional computer tools including Genefinder and ACeDB. Taken together, these methods and tools provide a powerful means for genome analysis in the nematode.
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[
1977]
The workshop on nematodes presented current research from four laboratories on the development and physiology of C. elegans.
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[
WormBook,
2008]
The role of neuropeptides in modulating behavior is slowly being elucidated. With the sequencing of the C. elegans genome, the extent of the neuropeptide genes in C. elegans can be determined. To date, 113 neuropeptide genes encoding over 250 distinct neuropeptides have been identified. Of these, 40 genes encode insulin-like peptides, 31 genes encode FMRFamide-related peptides, and 42 genes encode non-insulin, non-FMRFamide-related neuropeptides. As in other systems, C. elegans neuropeptides are derived from precursor molecules that must be post-translationally processed to yield the active peptides. These precursor molecules contain a single peptide, multiple copies of a single peptide, multiple distinct peptides, or any combination thereof. The neuropeptide genes are expressed extensively throughout the nervous system, including in sensory, motor, and interneurons. In addition, some of the genes are also expressed in non-neuronal tissues, such as the somatic gonad, intestine, and vulval hypodermis. To address the effects of neuropeptides on C. elegans behavior, animals in which the different neuropeptide genes are inactivated or overexpressed are being isolated. In a complementary approach the receptors to which the neuropeptides bind are also being identified and examined. Among the knockout animals analyzed thus far, defects in locomotion, dauer formation, egg laying, ethanol response, and social behavior have been reported. These data suggest that neuropeptides have a modulatory role in many, if not all, behaviors in C. elegans.
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Each year hundreds of students and practicing scientists join in the study of the soil nematode Caenorhabditis elegans. Their reasons for doing so are varied, but at the core these individuals are uniformly impressed by the cohesiveness and generosity of the C. elegans research community, the focused effort to understand every aspect of C. elegans biology, the power and flexibility of the...
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[
WormBook,
2005]
Nervous systems are characterized by an astounding degree of cellular diversity. The nematode Caenorhabditis elegans has served as a valuable model system to define the genetic programs that serve to generate cellular diversity in the nervous system. This review discusses neuronal diversity in C. elegans and provides an overview of the molecular mechanisms that define and specify neuronal cell types in C. elegans.
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[
WormBook,
2005]
A wide variety of bacterial pathogens, as well as several fungi, kill C. elegans or produce non-lethal disease symptoms. This allows the nematode to be used as a simple, tractable model host for infectious disease. Human pathogens that affect C. elegans include Gram-negative bacteria of genera Burkholderia, Pseudomonas, Salmonella, Serratia and Yersinia; Gram-positive bacteria Enterococcus, Staphylococcus and Streptococcus; and the fungus Cryptococcus neoformans. Microbes that are not pathogenic to mammals, such as the insect pathogen Bacillus thuringiensis and the nematode-specific Microbacterium nematophilum, are also studied with C. elegans. Many of the pathogens investigated colonize the C. elegans intestine, and pathology is usually quantified as decreased lifespan of the nematode. A few microbes adhere to the nematode cuticle, while others produce toxins that kill C. elegans without a requirement for whole, live pathogen cells to contact the worm. The rapid growth and short generation time of C. elegans permit extensive screens for mutant pathogens with diminished killing, and some of the factors identified in these screens have been shown to play roles in mammalian infections. Genetic screens for toxin-resistant C. elegans mutants have identified host pathways exploited by bacterial toxins.
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[
WormBook,
2005]
This chapter reviews analytical tools currently in use for protein classification, and gives an overview of the C. elegans proteome. Computational analysis of proteins relies heavily on hidden Markov models of protein families. Proteins can also be classified by predicted secondary or tertiary structures, hydrophobic profiles, compositional biases, or size ranges. Strictly orthologous protein families remain difficult to identify, except by skilled human labor. The InterPro and NCBI KOG classifications encompass 79% of C. elegans protein-coding genes; in both classifications, a small number of protein families account for a disproportionately large number of genes. C. elegans protein-coding genes include at least ~12,000 orthologs of C. briggsae genes, and at least ~4,400 orthologs of non-nematode eukaryotic genes. Some metazoan proteins conserved in other nematodes are absent from C. elegans. Conversely, 9% of C. elegans protein-coding genes are conserved among all metazoa or eukaryotes, yet have no known functions.