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[
Curr Biol,
2004]
Transcription is globally silenced in the germline of animals. Recent studies have shown that, in Caenorhabditis elegans, this silencing is initially mediated through direct repression, but in Drosophila, the factors involved include pgc, a non-coding cytoplasmic RNA. Why are these mechanisms so diverse and complex?
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Dev Cell,
2017]
Caspases have apoptotic and non-apoptotic functions, both of which depend on their abilities to cleave proteins at specific sites. What distinguishes apoptotic from non-apoptotic substrates has so far been unclear. In this issue of Developmental Cell, Weaver etal. (2017) now provide an answer to this crucial question.
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[
Trends Genet,
1994]
The heterochronic genes of Caenorhabditis elegans encode part of a regulatory system that controls the temporal component of cell fates in development. The genes have been characterized genetically and molecularly, and their study has so far revealed a genetic hierarchy that specifies sequences of developmental events, a novel RNA-mediated mechanism of gene regulation and a reprogramming phenomenon associated with arrested development.
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[
Proc. Fifth International Congress on Parasitology,
1982]
During the past ten years the nematode Caenorhabditis elegans has been subjected to intensive anatomical, genetic, developmental and behavioral analysis. More than 2500 mutants have been isolated; the complete developmental lineages of all embryonic and post embryonic cells have been determined; and the complete wiring diagram of its 300 neurons has been reconstructed by serial electron microscopy. Although C. elegans is a nonparasitic bacteria eating soil nematode and thus is not a proper subject for a parasitology congress, so much has been learned about this worm that it was elevated to honorary parasite status for this meeting. I will review some examples of how the genetic analysis of this helminth has helped established the function of parts of the sensory nervous system. Since the neuroanatomy of nematodes is so highly conserved these results should apply to parasitic nematodes as well.
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[
IUBMB Life,
2009]
Dauer is a dormancy state that may occur at the end of developmental stage L1 or L2 of Caenorhabditis elegans when the environmental conditions are unfavorable (e.g., lack of food, high temperature, or overcrowding) for further growth. Dauer is a nonaging duration that does not affect the postdauer adult lifespan. Major molecular events would include the sensing of the environmental cues, the transduction of the signals into the cells, and the subsequent integration of the signals that result in the corresponding alteration of the metabolism and morphology of the organism. Genetics approach has been effectively used in identifying many of the so-called daf genes involved in dauer formation using C. elegans as the model. Nevertheless, biochemical studies at the protein and metabolic level has been lacking behind in understanding this important life phenomenon. This review focuses on the biochemical understanding so far achieved on dauer formation and dormancy in general, as well as important issues that need to be addressed in the future.
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"The Testis: From Stell Cell to Sperm Function". E Goldberg (ed). Springer-Verlag, New York.,
2000]
In both mammals and C. elegans, spermatogenesis is the process where a spermatogonial cell undergoes a series of divisions to produce a highly differentiated cell, the spermatozoon. Spermatogonial cellular divisions are incomplete in mammals so that all subsequent stages occur in a syncitium. The situation is similar in C. elegans, where spermatogonial nuclei initially share a common cytoplasm. Spermatogonial divisions in both mammals and C. elegans are regulated by signaling from gonadal accessory
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Proc Biol Sci,
2014]
Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host-pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery.
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Parasitol Int,
2013]
Nicotinic acetylcholine receptors (nAChRs) play a key role in the normal physiology of nematodes and provide an established target site for anthelmintics. The free-living nematode, Caenorhabditis elegans, has a large number of nAChR subunit genes in its genome and so provides an experimental model for testing novel anthelmintics which act at these sites. However, many parasitic nematodes lack specific genes present in C. elegans, and so care is required in extrapolating from studies using C. elegans to the situation in other nematodes. In this review the properties of C. elegans nAChRs are reviewed and compared to those of parasitic nematodes. This forms the basis for a discussion of the possible subunit composition of nAChRs from different species of parasitic nematodes. Currently our knowledge on this is largely based on studies using heterologous expression and pharmacological analysis of receptor subunits in Xenopus laevis oocytes. It is concluded that more information is required regarding the subunit composition and pharmacology of endogenous nAChRs in parasitic nematodes.
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Costa M, Hunter CP, Harris JM, Maloof JN, Mueller-Immergluck MM, Salser SJ, Cowing DW, Wang BB, Austin JA, Honigberg LA, Kenyon CJ, Waring DA, Wrischnik LA
[
Cold Spring Harb Symp Quant Biol,
1997]
Hox mutations are fascinating. Like magic, they can turn antennae into legs or create extra wings. What makes these genes so talented? How can they make such high-level decisions? Are there simple rules that can explain the effects they have on the development of individual cells? Do the genes act multiple times during the development of a tissue to micromanage individual cell fate decisions, or can they act relatively early to initiate developmental programs that run independently of their further input?
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Dev Biol,
2011]
Foxa is a forkhead transcription factor that is expressed in the endoderm lineage across metazoans. Orthologs of foxa are expressed in cells that intercalate, polarize, and form tight junctions in the digestive tracts of the mouse, the sea urchin, and the nematode and in the chordate notochord. The loss of foxa expression eliminates these morphogenetic processes. The remarkable similarity in foxa phenotypes in these diverse organisms raises the following questions: why is the developmental role of Foxa so highly conserved? Is foxa transcriptional regulation as conserved as its developmental role? Comparison of the regulation of foxa orthologs in sea urchin and in Caenorhabditis elegans shows that foxa transcriptional regulation has diverged significantly between these two organisms, particularly in the cells that contribute to the C. elegans pharynx formation. We suggest that the similarity of foxa phenotype is due to its role in an ancestral gene regulatory network that controlled intercalation followed by mesenchymal-to-epithelial transition. foxa transcriptional regulation had evolved to support the developmental program in each species so foxa would play its role controlling morphogenesis at the necessary embryonic address.