Anterior-posterior patterning within the Caenorhabditis elegans endoderm

Development ◽  
1998 ◽  
Vol 125 (24) ◽  
pp. 4877-4887 ◽  
Author(s):  
D.F. Schroeder ◽  
J.D. McGhee
Keyword(s):  
Caenorhabditis Elegans ◽  
Signalling Pathway ◽  
Cell Contact ◽  
Specific Cell ◽  
Homeotic Genes ◽  
C Elegans ◽  
Marker Expression ◽  
Uniform Tube ◽  
Gut Patterning ◽  
Anterior Posterior

The endoderm of higher organisms is extensively patterned along the anterior/posterior axis. Although the endoderm (gut or E lineage) of the nematode Caenorhabditis elegans appears to be a simple uniform tube, cells in the anterior gut show several molecular and anatomical differences from cells in the posterior gut. In particular, the gut esterase ges-1 gene, which is normally expressed in all cells of the endoderm, is expressed only in the anterior-most gut cells when certain sequences in the ges-1 promoter are deleted. Using such a deleted ges-1 transgene as a biochemical marker of differentiation, we have investigated the basis of anterior-posterior gut patterning in C. elegans. Although homeotic genes are involved in endoderm patterning in other organisms, we show that anterior gut markers are expressed normally in C. elegans embryos lacking genes of the homeotic cluster. Although signalling from the mesoderm is involved in endoderm patterning in other organisms, we show that ablation of all non-gut blastomeres from the C. elegans embryo does not affect anterior gut marker expression; furthermore, ectopic guts produced by genetic transformation express anterior gut markers generally in the expected location and in the expected number of cells. We conclude that anterior gut fate requires no specific cell-cell contact but rather is produced autonomously within the E lineage. Cytochalasin D blocking experiments fully support this conclusion. Finally, the HMG protein POP-1, a downstream component of the Wnt signalling pathway, has recently been shown to be important in many anterior/posterior fate decisions during C. elegans embryogenesis (Lin, R., Hill, R. J. and Priess, J. R. (1998) Cell 92, 229–239). When RNA-mediated interference is used to eliminate pop-1 function from the embryo, gut is still produced but anterior gut marker expression is abolished. We suggest that the C. elegans endoderm is patterned by elements of the Wnt/pop-1 signalling pathway acting autonomously within the E lineage.

scholarly journals Cell contacts orient some cell division axes in the Caenorhabditis elegans embryo.

1995 ◽  
Vol 129 (4) ◽  
pp. 1071-1080 ◽  
Author(s):  
B Goldstein
Keyword(s):  
Cell Division ◽  
Caenorhabditis Elegans ◽  
Mitotic Spindle ◽  
Spindle Orientation ◽  
Cell Contact ◽  
Specific Cell ◽  
Cell Contacts ◽  
Established Cell ◽  
A Site ◽  
Cell Cell

Cells of the early Caenorhabditis elegans embryo divide in an invariant pattern. Here I show that the division axes of some early cells (EMS and E) are controlled by specific cell-cell contacts (EMS-P2 or E-P3 contact). Altering the orientation of contact between these cells alters the axis along which the mitotic spindle is established, and hence the orientation of cell division. Contact-dependent mitotic spindle orientation appears to work by establishing a site of the type described by Hyman and White (1987. J. Cell Biol. 105:2123-2135) in the cortex of the responding cell: one centrosome moves toward the site of cell-cell contact during centrosome rotation in both intact embryos and reoriented cell pairs. The effect is especially apparent when two donor cells are placed on one side of the responding cell: both centrosomes are "captured," pulling the nucleus to one side of the cell. No centrosome rotation occurs in the absence of cell-cell contact, nor in nocodazole-treated cell pairs. The results suggest that some of the cortical sites described by Hyman and White are established cell autonomously (in P1, P2, and P3), and some are established by cell-cell contact (in EMS and E). Additional evidence presented here suggests that in the EMS cell, contact-dependent spindle orientation ensures a cleavage plane that will partition developmental information, received by induction, to one of EMS's daughter cells.

scholarly journals Gengnianchun Extends the Lifespan of Caenorhabditis elegans via the Insulin/IGF-1 Signalling Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Fanhui Meng ◽  
Jun Li ◽  
Yanqiu Rao ◽  
Wenjun Wang ◽  
Yan Fu
Keyword(s):  
Thermal Stress ◽  
Caenorhabditis Elegans ◽  
Chinese Medicine ◽  
Stress Resistance ◽  
Antioxidant Properties ◽  
Signalling Pathway ◽  
Rna Seq ◽  
C Elegans ◽  
Beneficial Effects ◽  
Mutant Strains

Gengnianchun (GNC), a traditional Chinese medicine (TCM), is believed to have beneficial effects on ageing-related diseases, such as antioxidant properties and effects against Aβ-induced toxicity. We previously found that GNC extended the lifespan of Caenorhabditis elegans. However, the mechanism underlying this effect was unclear. In this study, we further explored the mechanisms of GNC using a C. elegans model. GNC significantly increased the lifespan of C. elegans and enhanced oxidative and thermal stress resistance. Moreover, chemotaxis increased after GNC treatment. RNA-seq analysis showed that GNC regulated genes associated with longevity. We also conducted lifespan assays with a series of worm mutants. The results showed that GNC significantly extended the lifespan of several mutant strains, including eat-2 (ad465), rsks-1 (ok1255), and glp-1 (e2144), suggesting that the prolongevity effect of GNC is independent of the function of these genes. However, GNC failed to extend the lifespan of daf-2 (e1370), age-1 (hx546), and daf-16 (mu86) mutant strains. Our findings suggest that GNC extends the lifespan of C. elegans via the insulin/IGF-1 signalling pathway and may be a potential antiageing agent.

scholarly journals Caenorhabditis elegans β-G Spectrin Is Dispensable for Establishment of Epithelial Polarity, but Essential for Muscular and Neuronal Function

2000 ◽  
Vol 149 (4) ◽  
pp. 915-930 ◽  
Author(s):  
Suraj Moorthy ◽  
Lihsia Chen ◽  
Vann Bennett
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Expression Patterns ◽  
Cell Contact ◽  
Epithelial Polarity ◽  
Cell Stage ◽  
C Elegans ◽  
Cell Cell

The Caenorhabditis elegans genome encodes one α spectrin subunit, a β spectrin subunit (β-G), and a β-H spectrin subunit. Our experiments show that the phenotype resulting from the loss of the C. elegans α spectrin is reproduced by tandem depletion of both β-G and β-H spectrins. We propose that α spectrin combines with the β-G and β-H subunits to form α/β-G and α/β-H heteromers that perform the entire repertoire of spectrin function in the nematode. The expression patterns of nematode β-G spectrin and vertebrate β spectrins exhibit three striking parallels including: (1) β spectrins are associated with the sites of cell–cell contact in epithelial tissues; (2) the highest levels of β-G spectrin occur in the nervous system; and (3) β spec-trin-G in striated muscle is associated with points of attachment of the myofilament apparatus to adjacent cells. Nematode β-G spectrin associates with plasma membranes at sites of cell–cell contact, beginning at the two-cell stage, and with a dramatic increase in intensity after gastrulation when most cell proliferation has been completed. Strikingly, depletion of nematode β-G spectrin by RNA-mediated interference to undetectable levels does not affect the establishment of structural and functional polarity in epidermis and intestine. Contrary to recent speculation, β-G spectrin is not associated with internal membranes and depletion of β-G spectrin was not associated with any detectable defects in secretion. Instead β-G spectrin-deficient nematodes arrest as early larvae with progressive defects in the musculature and nervous system. Therefore, C. elegans β-G spectrin is required for normal muscle and neuron function, but is dispensable for embryonic elongation and establishment of early epithelial polarity. We hypothesize that heteromeric spectrin evolved in metazoans in response to the needs of cells in the context of mechanically integrated tissues that can withstand the rigors imposed by an active organism.

scholarly journals Establishment of a morphological atlas of the Caenorhabditis elegans embryo using deep-learning-based 4D segmentation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jianfeng Cao ◽  
Guoye Guan ◽  
Vincy Wing Sze Ho ◽  
Ming-Kin Wong ◽  
Lu-Yan Chan ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Fate ◽  
Cell Morphology ◽  
Cell Biology ◽  
Cell Lineage ◽  
Time Lapse ◽  
Lineage Tracing ◽  
Cell Contact ◽  
C Elegans ◽  
Division Cell

AbstractThe invariant development and transparent body of the nematode Caenorhabditis elegans enables complete delineation of cell lineages throughout development. Despite extensive studies of cell division, cell migration and cell fate differentiation, cell morphology during development has not yet been systematically characterized in any metazoan, including C. elegans. This knowledge gap substantially hampers many studies in both developmental and cell biology. Here we report an automatic pipeline, CShaper, which combines automated segmentation of fluorescently labeled membranes with automated cell lineage tracing. We apply this pipeline to quantify morphological parameters of densely packed cells in 17 developing C. elegans embryos. Consequently, we generate a time-lapse 3D atlas of cell morphology for the C. elegans embryo from the 4- to 350-cell stages, including cell shape, volume, surface area, migration, nucleus position and cell-cell contact with resolved cell identities. We anticipate that CShaper and the morphological atlas will stimulate and enhance further studies in the fields of developmental biology, cell biology and biomechanics.

scholarly journals Overlapping and non-overlapping roles of the class-I histone deacetylase-1 corepressors LET-418, SIN-3, and SPR-1 in Caenorhabditis elegans embryonic development

2021 ◽  
Author(s):  
Yukihiro Kubota ◽  
Yuto Ohnishi ◽  
Tasuku Hamasaki ◽  
Gen Yasui ◽  
Natsumi Ota ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Embryonic Development ◽  
Histone Deacetylase ◽  
Genetic Interactions ◽  
Class I ◽  
Specific Cell ◽  
Nucleosome Remodeling ◽  
Expression Levels ◽  
C Elegans ◽  
Functional Relationships

AbstractBackgroundHistone deacetylase (HDAC)-1, a Class-I HDAC family member, forms three types of complexes, the nucleosome remodeling deacetylase, Sin3, and CoREST complexes with the specific corepressor components chromodomain-helicase-DNA-binding protein 3 (Mi2/CHD-3), Sin3, and REST corepressor 1 (RCOR1), respectively, in humans.ObjectiveTo elucidate the functional relationships among the three transcriptional corepressors during embryogenesis.MethodsThe activities of HDA-1, LET-418, SIN-3, and SPR-1, the homologs of HDAC-1, Mi2, Sin3, and RCOR1 inCaenorhabditis elegansduring embryogenesis were investigated through measurement of relative mRNA expression levels and embryonic lethality given either gene knockdown or deletion. Additionally, the terminal phenotypes of each knockdown and mutant embryo were observed using a differential-interference contrast microscope. Finally, the functional relationships among the three corepressors were examined through genetic interactions and transcriptome analyses.ResultsHere, we report that each of the corepressors LET-418, SIN-3, and SPR-1 are expressed and have essential roles inC. elegansembryonic development. Our terminal phenotype observations of single mutants further implied that LET-418, SIN-3, and SPR-1 play similar roles in promoting advancement to the middle and late embryonic stages. Combined analysis of genetic interactions and gene ontology of these corepressors indicate a prominent overlapping role among SIN-3, SPR-1, and LET-418 and between SIN-3 and SPR-1.ConclusionOur findings suggest that the class-I HDAC-1 corepressors LET-418, SIN-3, and SPR-1 may cooperatively regulate the expression levels of some genes duringC. elegansembryogenesis or may have some similar roles but functioning independently within a specific cell.

scholarly journals Mosaic Analysis Using a ncl-1 (+) Extrachromosomal Array Reveals That lin-31 Acts in the Pn.p Cells During Caenorhabditis elegans Vulval Development

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1181-1191 ◽  
Author(s):  
Leilani M Miller ◽  
David A Waxing ◽  
Stuart K Kim
Keyword(s):  
Caenorhabditis Elegans ◽  
The Body ◽  
Specific Cell ◽  
Vulval Development ◽  
C Elegans ◽  
Genetic Mosaic ◽  
Extrachromosomal Array ◽  
Mosaic Analysis ◽  
Putative Transcription Factor ◽  
Sites Of Action

Abstract We describe a genetic mosaic analysis procedure in which Caenorhabditis elegans mosaics are generated by spontaneous loss of an extrachromosomal array. This technique allows almost any C. elegans gene that can be used in germline transformation experiments to be used in mosaic analysis experiments. We identified a cosmid clone that rescues the mutant phenotype of ncl-1, so that this cell-autonomous marker could be used to analyze mosaic animals. To determine the sites of action for unc-29 and lin-31, an extrachromosomal array was constructed containing the ncl-1(+) cosmid linked to lin-31(+) and unc-29(+) cosmids. This array is mitotically unstable and can be lost to produce a clone of mutant cells. The specific cell division at which the extrachromosomal array had been lost was deduced by scoring the Ncl phenotypes of individual cells in genetic mosaics. The Unc-29 and Lin-31 phenotypes were then scored in these animals to determine in which cells these genes are required. This analysis showed that unc-29, which encodes a subunit of the acetylcholine receptor, acts in the body muscle cells. Furthermore, lin-31, which specifies cell fates during vulval induction and encodes a putative transcription factor similar to HNF-3/fork head, acts in the Pn.p cells

Anterior organization of the Caenorhabditis elegans embryo by the labial-like Hox gene ceh-13

Development ◽  
1999 ◽  
Vol 126 (7) ◽  
pp. 1537-1546 ◽  
Author(s):  
K. Brunschwig ◽  
C. Wittmann ◽  
R. Schnabel ◽  
T.R. Burglin ◽  
H. Tobler ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Hox Genes ◽  
Postembryonic Development ◽  
Loss Of Function ◽  
Expression Domain ◽  
Cell Fates ◽  
Hox Gene ◽  
C Elegans ◽  
Anterior Body ◽  
Anterior Posterior

The Caenorhabditis elegans lin-39, mab-5 and egl-5 Hox genes specify cell fates along the anterior-posterior body axis of the nematode during postembryonic development, but little is known about Hox gene functions during embryogenesis. Here, we show that the C. elegans labial-like gene ceh-13 is expressed in cells of many different tissues and lineages and that the rostral boundary of its expression domain is anterior to those of the other Hox genes. By transposon-mediated mutagenesis, we isolated a zygotic recessive ceh-13 loss-of-function allele, sw1, that exhibits an embryonic sublethal phenotype. Lineage analyses and immunostainings revealed defects in the organization of the anterior lateral epidermis and anterior body wall muscle cells. The epidermal and mesodermal identity of these cells, however, is correctly specified. ceh-13(sw1) mutant embryos also show fusion and adhesion defects in ectodermal cells. This suggests that ceh-13 plays a role in the anterior organization of the C. elegans embryo and is involved in the regulation of cell affinities.

scholarly journals Cytoplasmic streaming drifts the polarity cue and specifies the cell polarity in Caenorhabditis elegans zygotes

2019 ◽  
Author(s):  
Kenji Kimura ◽  
Akatsuki Kimura
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Polarity ◽  
Cytoplasmic Streaming ◽  
The Body ◽  
Cell Cortex ◽  
Spatial Cues ◽  
Entry Site ◽  
C Elegans ◽  
Sperm Entry ◽  
Anterior Posterior

AbstractCell polarisation is required to define body axes during development. The position of spatial cues for polarisation is critical to direct the body axes. In Caenorhabditis elegans zygotes, the sperm-derived pronucleus/centrosome complex (SPCC) serves as the spatial cue to specify the anterior–posterior axis. Approximately 30 minutes after fertilisation, the contractility of the cell cortex is relaxed near the SPCC, which is the earliest sign of polarisation and called symmetry breaking (SB). It is unclear how the position of SPCC at SB is determined after fertilisation. Here, we show that SPCC drifts dynamically through the cell-wide flow of the cytoplasm, called meiotic cytoplasmic streaming. This flow occasionally brings SPCC to the opposite side of the sperm entry site before SB. Our results demonstrate that cytoplasmic flow determines stochastically the position of the spatial cue of the body axis, even in an organism like C. elegans for which development is stereotyped.

Expression of the homeotic gene mab-5 during Caenorhabditis elegans embryogenesis

Development ◽  
1992 ◽  
Vol 116 (2) ◽  
pp. 481-490 ◽  
Author(s):  
D.W. Cowing ◽  
C. Kenyon
Keyword(s):  
Early Stage ◽  
Postembryonic Development ◽  
Early Embryogenesis ◽  
Lacz Fusion ◽  
Homeotic Genes ◽  
Specific Expression ◽  
C Elegans ◽  
Developmental Factors ◽  
Cell Embryo ◽  
Anterior Posterior

mab-5 is a member of a complex of homeobox-containing genes evolutionarily related to the Antennapedia and bithorax complexes of Drosophila melanogaster. Like the homeotic genes in Drosophila, mab-5 is required in a particular region along the anterior-posterior body axis, and acts during postembryonic development to give cells in this region their characteristic identities. We have used a mab-5-lacZ fusion integrated into the C. elegans genome to study the posterior-specific expression of mab-5 during embryogenesis. The mab-5-lacZ fusion was expressed in the posterior of the embryo by 180 minutes after the first cleavage, indicating that the mechanisms responsible for the position-specific expression of mab-5-lacZ act at a relatively early stage of embryogenesis. In embryos homozygous for mutations in the par genes, which disrupt segregation of factors during early cleavages, expression of mab-5-lacZ was no longer localized to the posterior. This suggests that posterior-specific expression of mab-5 depends on the appropriate segregation of developmental factors during early embryogenesis. After extrusion of any blastomere of the four-cell embryo, descendants of the remaining three cells could still express the mab-5-lacZ fusion. In these partial embryos, however, the fusion was often expressed in cells scattered throughout the embryo, suggesting that cell-cell interactions and/or proper positioning of early blastomeres are required for mab-5 expression to be localized to the posterior.

scholarly journals The Nonmuscle Myosin Regulatory Light Chain Gene mlc-4 Is Required for Cytokinesis, Anterior-Posterior Polarity, and Body Morphology during Caenorhabditis elegans Embryogenesis

1999 ◽  
Vol 146 (2) ◽  
pp. 439-451 ◽  
Author(s):  
Christopher A. Shelton ◽  
J. Clayton Carter ◽  
Gregory C. Ellis ◽  
Bruce Bowerman
Keyword(s):  
Caenorhabditis Elegans ◽  
Light Chain ◽  
Myosin Ii ◽  
Regulatory Light Chain ◽  
Chain Gene ◽  
Nonmuscle Myosin ◽  
Light Chain Gene ◽  
C Elegans ◽  
Nonmuscle Myosin Ii ◽  
Anterior Posterior

Using RNA-mediated genetic interference in a phenotypic screen, we identified a conserved nonmuscle myosin II regulatory light chain gene in Caenorhabditis elegans, which we name mlc-4. Maternally supplied mlc-4 function is required for cytokinesis during both meiosis and mitosis and for establishment of anterior-posterior (a-p) asymmetries after fertilization. Reducing the function of mlc-4 or nmy-2, a nonmuscle myosin II gene, also leads to a loss of polarized cytoplasmic flow in the C. elegans zygote, supporting models in which cytoplasmic flow may be required to establish a-p differences. Germline P granule localization at the time of cytoplasmic flow is also lost in these embryos, although P granules do become localized to the posterior pole after the first mitosis. This result suggests that a mechanism other than cytoplasmic flow or mlc-4/nmy-2 activity can generate some a-p asymmetries in the C. elegans zygote. By isolating a deletion allele, we show that removing zygotic mlc-4 function results in an elongation phenotype during embryogenesis. An mlc-4/green fluorescent protein transgene is expressed in lateral rows of hypodermal cells and these cells fail to properly change shape in mlc-4 mutant animals during elongation.

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