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A Transparent Window into Biology: A Primer on Caenorhabditis elegans.

Corsi AK, Wightman B, Chalfie M - Genetics (2015)

Bottom Line: We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research.Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell.These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues.

View Article: PubMed Central - PubMed

Affiliation: Biology Department, The Catholic University of America, Washington, DC 20064 corsi@cua.edu wightman@muhlenberg.edu mc21@columbia.edu.

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Related in: MedlinePlus

Anatomy and study of the C. elegans nervous system. (A) Diagram of the C. elegans nervous system identifying some major nerve bundles and ganglia. Major nerve tracts include the ventral nerve cord (VNC), dorsal nerve cord (DNC), and nerve ring. Major ganglia include the ring ganglia, retrovesicular ganglion (RVG), preanal ganglion (PAG), and dorsal-root ganglion (DRG). Image was produced using the OpenWorm browser utility (openworm.org). (B) Visualization of anterior sensory neurons and their neurite projections by expression of a GFP reporter transgene. The Y105E8A.5::GFP fusion transgene is expressed in amphid, OL, and IL sensory neurons of the head (R. Newbury and D. Moerman, Wormatlas; wormatlas.org). (C) Use of cameleon reporter transgene to detect calcium transients in the C. eleganspharynx. The animal carries a transgene with myo-2, a pharynx-specific myosin gene, fused to YC2.1, a calcium-sensitive fluorescent detector. False-color red in the pharyngeal bulb reflects real-time calcium releases in the cell of the living animal. Image was adapted from Kerr et al. (2000). (D) Electron microscopic section showing synapses. Collections of densely staining vesicles can be seen in neuron 1 at the point of synaptic connection to neurons 2 and 3 (arrows). Synaptic varicosities (V) that contain vesicles can be seen clustered around the active zone. DCV identifies a dense-core vesicle. Image is from D. Hall (Wormatlas; wormatlas.org). (E) Worm behavior on a bacterial plate. Left image shows the standard laboratory N2 strain foraging as individuals evenly dispersed across the bacterial food. Right image shows an npr-1 mutant strain foraging in grouped masses (sometimes called a “social” feeding phenotype). Image is from M. de Bono, taken from Schafer (2005).
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fig4: Anatomy and study of the C. elegans nervous system. (A) Diagram of the C. elegans nervous system identifying some major nerve bundles and ganglia. Major nerve tracts include the ventral nerve cord (VNC), dorsal nerve cord (DNC), and nerve ring. Major ganglia include the ring ganglia, retrovesicular ganglion (RVG), preanal ganglion (PAG), and dorsal-root ganglion (DRG). Image was produced using the OpenWorm browser utility (openworm.org). (B) Visualization of anterior sensory neurons and their neurite projections by expression of a GFP reporter transgene. The Y105E8A.5::GFP fusion transgene is expressed in amphid, OL, and IL sensory neurons of the head (R. Newbury and D. Moerman, Wormatlas; wormatlas.org). (C) Use of cameleon reporter transgene to detect calcium transients in the C. eleganspharynx. The animal carries a transgene with myo-2, a pharynx-specific myosin gene, fused to YC2.1, a calcium-sensitive fluorescent detector. False-color red in the pharyngeal bulb reflects real-time calcium releases in the cell of the living animal. Image was adapted from Kerr et al. (2000). (D) Electron microscopic section showing synapses. Collections of densely staining vesicles can be seen in neuron 1 at the point of synaptic connection to neurons 2 and 3 (arrows). Synaptic varicosities (V) that contain vesicles can be seen clustered around the active zone. DCV identifies a dense-core vesicle. Image is from D. Hall (Wormatlas; wormatlas.org). (E) Worm behavior on a bacterial plate. Left image shows the standard laboratory N2 strain foraging as individuals evenly dispersed across the bacterial food. Right image shows an npr-1 mutant strain foraging in grouped masses (sometimes called a “social” feeding phenotype). Image is from M. de Bono, taken from Schafer (2005).

Mentions: Studies of cell and developmental biology that use C. elegans are greatly aided by the transparency of the animal, which allows researchers to examine development and changes due to mutations or altered environments at the level of a single, identified cell within the context of the entire living organism. Thus, many biological problems can be studied “in miniature” at the single-cell level, instead of in large numbers of cells in heterogeneous tissues. Transparency also enables a wealth of studies in living animals utilizing fluorescent protein reporters (Figure 1D and Figure 4B). By labeling cells and proteins in living cells, fluorescent proteins enable genetic screens to identify mutants defective in various cellular processes. In addition, fluorescent protein-based reporters (e.g., Cameleon and gCaMP3; Figure 4C), which fluoresce in response to calcium flux, provide neuron-specific detection of calcium flux under a fluorescent microscope and therefore allow researchers to measure electrophysiological activity in vivo (Kerr 2006). Furthermore, mapping of cell–cell and synaptic contacts can be accomplished by expressing complementary fragments of GFP in different cells (GRASP; Feinberg et al. 2008). Transparency also means that optogenetic tools, which alter the activity of individual neurons, are particularly effective in C. elegans (Husson et al. 2013). In all of these experiments, greater control of the animal’s position and environment can be accomplished by microfluidic devices in which individual worms are mounted in custom-designed channels allowing the application of various compounds or other agents while simultaneously monitoring fluorescent readout of gene regulation or electrophysiological activity by microscopy (Lockery 2007; San-Miguel and Lu 2013).


A Transparent Window into Biology: A Primer on Caenorhabditis elegans.

Corsi AK, Wightman B, Chalfie M - Genetics (2015)

Anatomy and study of the C. elegans nervous system. (A) Diagram of the C. elegans nervous system identifying some major nerve bundles and ganglia. Major nerve tracts include the ventral nerve cord (VNC), dorsal nerve cord (DNC), and nerve ring. Major ganglia include the ring ganglia, retrovesicular ganglion (RVG), preanal ganglion (PAG), and dorsal-root ganglion (DRG). Image was produced using the OpenWorm browser utility (openworm.org). (B) Visualization of anterior sensory neurons and their neurite projections by expression of a GFP reporter transgene. The Y105E8A.5::GFP fusion transgene is expressed in amphid, OL, and IL sensory neurons of the head (R. Newbury and D. Moerman, Wormatlas; wormatlas.org). (C) Use of cameleon reporter transgene to detect calcium transients in the C. eleganspharynx. The animal carries a transgene with myo-2, a pharynx-specific myosin gene, fused to YC2.1, a calcium-sensitive fluorescent detector. False-color red in the pharyngeal bulb reflects real-time calcium releases in the cell of the living animal. Image was adapted from Kerr et al. (2000). (D) Electron microscopic section showing synapses. Collections of densely staining vesicles can be seen in neuron 1 at the point of synaptic connection to neurons 2 and 3 (arrows). Synaptic varicosities (V) that contain vesicles can be seen clustered around the active zone. DCV identifies a dense-core vesicle. Image is from D. Hall (Wormatlas; wormatlas.org). (E) Worm behavior on a bacterial plate. Left image shows the standard laboratory N2 strain foraging as individuals evenly dispersed across the bacterial food. Right image shows an npr-1 mutant strain foraging in grouped masses (sometimes called a “social” feeding phenotype). Image is from M. de Bono, taken from Schafer (2005).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4492366&req=5

fig4: Anatomy and study of the C. elegans nervous system. (A) Diagram of the C. elegans nervous system identifying some major nerve bundles and ganglia. Major nerve tracts include the ventral nerve cord (VNC), dorsal nerve cord (DNC), and nerve ring. Major ganglia include the ring ganglia, retrovesicular ganglion (RVG), preanal ganglion (PAG), and dorsal-root ganglion (DRG). Image was produced using the OpenWorm browser utility (openworm.org). (B) Visualization of anterior sensory neurons and their neurite projections by expression of a GFP reporter transgene. The Y105E8A.5::GFP fusion transgene is expressed in amphid, OL, and IL sensory neurons of the head (R. Newbury and D. Moerman, Wormatlas; wormatlas.org). (C) Use of cameleon reporter transgene to detect calcium transients in the C. eleganspharynx. The animal carries a transgene with myo-2, a pharynx-specific myosin gene, fused to YC2.1, a calcium-sensitive fluorescent detector. False-color red in the pharyngeal bulb reflects real-time calcium releases in the cell of the living animal. Image was adapted from Kerr et al. (2000). (D) Electron microscopic section showing synapses. Collections of densely staining vesicles can be seen in neuron 1 at the point of synaptic connection to neurons 2 and 3 (arrows). Synaptic varicosities (V) that contain vesicles can be seen clustered around the active zone. DCV identifies a dense-core vesicle. Image is from D. Hall (Wormatlas; wormatlas.org). (E) Worm behavior on a bacterial plate. Left image shows the standard laboratory N2 strain foraging as individuals evenly dispersed across the bacterial food. Right image shows an npr-1 mutant strain foraging in grouped masses (sometimes called a “social” feeding phenotype). Image is from M. de Bono, taken from Schafer (2005).
Mentions: Studies of cell and developmental biology that use C. elegans are greatly aided by the transparency of the animal, which allows researchers to examine development and changes due to mutations or altered environments at the level of a single, identified cell within the context of the entire living organism. Thus, many biological problems can be studied “in miniature” at the single-cell level, instead of in large numbers of cells in heterogeneous tissues. Transparency also enables a wealth of studies in living animals utilizing fluorescent protein reporters (Figure 1D and Figure 4B). By labeling cells and proteins in living cells, fluorescent proteins enable genetic screens to identify mutants defective in various cellular processes. In addition, fluorescent protein-based reporters (e.g., Cameleon and gCaMP3; Figure 4C), which fluoresce in response to calcium flux, provide neuron-specific detection of calcium flux under a fluorescent microscope and therefore allow researchers to measure electrophysiological activity in vivo (Kerr 2006). Furthermore, mapping of cell–cell and synaptic contacts can be accomplished by expressing complementary fragments of GFP in different cells (GRASP; Feinberg et al. 2008). Transparency also means that optogenetic tools, which alter the activity of individual neurons, are particularly effective in C. elegans (Husson et al. 2013). In all of these experiments, greater control of the animal’s position and environment can be accomplished by microfluidic devices in which individual worms are mounted in custom-designed channels allowing the application of various compounds or other agents while simultaneously monitoring fluorescent readout of gene regulation or electrophysiological activity by microscopy (Lockery 2007; San-Miguel and Lu 2013).

Bottom Line: We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research.Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell.These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues.

View Article: PubMed Central - PubMed

Affiliation: Biology Department, The Catholic University of America, Washington, DC 20064 corsi@cua.edu wightman@muhlenberg.edu mc21@columbia.edu.

Show MeSH
Related in: MedlinePlus