scholarly journals Cell polarity–dependent centrosome separation in the C. elegans embryo

2019 ◽  
Vol 218 (12) ◽  
pp. 4112-4126
Author(s):  
Alexandra Bondaz ◽  
Luca Cirillo ◽  
Patrick Meraldi ◽  
Monica Gotta
Keyword(s):  
Cell Polarity ◽  
Cell Biology ◽  
Dependent Manner ◽  
Animal Cells ◽  
Cell Stage ◽  
C Elegans ◽  
Mitotic Kinase ◽  
Centrosome Separation ◽  
A Cell ◽  
Cortical Localization

In animal cells, faithful chromosome segregation depends on the assembly of a bipolar spindle driven by the timely separation of the two centrosomes. Here we took advantage of the highly stereotypical cell divisions in Caenorhabditis elegans embryos to identify new regulators of centrosome separation. We find that at the two-cell stage, the somatic AB cell initiates centrosome separation later than the germline P1 cell. This difference is strongly exacerbated by the depletion of the kinesin-13 KLP-7/MCAK, resulting in incomplete centrosome separation at NEBD in AB but not P1. Our genetic and cell biology data indicate that this phenotype depends on cell polarity via the enrichment in AB of the mitotic kinase PLK-1, which itself limits the cortical localization of the dynein-binding NuMA orthologue LIN-5. We postulate that the timely separation of centrosomes is regulated in a cell type–dependent manner.

scholarly journals Microinjection into the Caenorhabditis elegans embryo using an uncoated glass needle enables cell lineage visualization and reveals cell-non-autonomous adhesion control

2018 ◽  
Author(s):  
Yohei Kikuchi ◽  
Akatsuki Kimura
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Biology ◽  
Cell Lineage ◽  
Special Equipment ◽  
Cell Stage ◽  
C Elegans ◽  
Carbon Coated ◽  
A Cell ◽  
Glass Needle ◽  
Time Specific

AbstractMicroinjection is a useful method in cell biology, with which exogenous substances are introduced into a cell in a location- and time-specific manner. The Caenorhabditis elegans embryo is an important model system for cell and developmental biology. Applying microinjection to the C. elegans embryo had been difficult due to the rigid eggshell surrounding the embryo. In 2013, microinjection method using a carbon-coated quartz needle for the C. elegans embryo was reported. To prepare the needle, unfortunately, special equipment is required and thus a limited number of researchers can use this method. In this study, we established a method for the microinjection of drugs, dyes, and microbeads into the C. elegans embryo using an uncoated glass needle that can be produced in a general laboratory. This method enabled us to easily detect cell lineage up to adult stages by injecting a fluorescent dye into a blastomere. We also found a cell-non-autonomous control mechanism of cell adhesion; specifically, the injection of an actin inhibitor into one cell at the 2-cell stage enhanced adhesion between daughter cells of the other cell. Our microinjection method is expected to be used for broad studies and could facilitate various discoveries using C. elegans.

scholarly journals PLK-1 Regulation of Asymmetric Cell Division in the Early C. elegans Embryo

2021 ◽  
Vol 8 ◽  
Author(s):  
Amelia J. Kim ◽  
Erik E. Griffin
Keyword(s):  
Cell Division ◽  
Cell Fate ◽  
Cell Polarity ◽  
Planar Cell Polarity ◽  
Asymmetric Cell Division ◽  
Critical Role ◽  
Cell Cortex ◽  
C Elegans ◽  
Mitotic Kinase ◽  
Centrosome Separation

PLK1 is a conserved mitotic kinase that is essential for the entry into and progression through mitosis. In addition to its canonical mitotic functions, recent studies have characterized a critical role for PLK-1 in regulating the polarization and asymmetric division of the one-cell C. elegans embryo. Prior to cell division, PLK-1 regulates both the polarization of the PAR proteins at the cell cortex and the segregation of cell fate determinants in the cytoplasm. Following cell division, PLK-1 is preferentially inherited to one daughter cell where it acts to regulate the timing of centrosome separation and cell division. PLK1 also regulates cell polarity in asymmetrically dividing Drosophila neuroblasts and during mammalian planar cell polarity, suggesting it may act broadly to connect cell polarity and cell cycle mechanisms.

scholarly journals H3K27 modifiers regulate lifespan in C. elegans in a context-dependent manner

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Abigail R. R. Guillermo ◽  
Karolina Chocian ◽  
Gavriil Gavriilidis ◽  
Julien Vandamme ◽  
Anna Elisabetta Salcini ◽  
...  
Keyword(s):  
Lifespan Extension ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Animal Cells ◽  
C Elegans ◽  
Specific Effects ◽  
Aberrant Gene Expression ◽  
Lysine Methyltransferase ◽  
Epigenetic Signatures ◽  
Aberrant Gene

Abstract Background Evidence of global heterochromatin decay and aberrant gene expression in models of physiological and premature ageing have long supported the “heterochromatin loss theory of ageing”, which proposes that ageing is aetiologically linked to, and accompanied by, a progressive, generalised loss of repressive epigenetic signatures. However, the remarkable plasticity of chromatin conformation suggests that the re-establishment of such marks could potentially revert the transcriptomic architecture of animal cells to a “younger” state, promoting longevity and healthspan. To expand our understanding of the ageing process and its connection to chromatin biology, we screened an RNAi library of chromatin-associated factors for increased longevity phenotypes. Results We identified the lysine demethylases jmjd-3.2 and utx-1, as well as the lysine methyltransferase mes-2 as regulators of both lifespan and healthspan in C. elegans. Strikingly, we found that both overexpression and loss of function of jmjd-3.2 and utx-1 are all associated with enhanced longevity. Furthermore, we showed that the catalytic activity of UTX-1, but not JMJD-3.2, is critical for lifespan extension in the context of overexpression. In attempting to reconcile the improved longevity associated with both loss and gain of function of utx-1, we investigated the alternative lifespan pathways and tissue specificity of longevity outcomes. We demonstrated that lifespan extension caused by loss of utx-1 function is daf-16 dependent, while overexpression effects are partially independent of daf-16. In addition, lifespan extension was observed when utx-1 was knocked down or overexpressed in neurons and intestine, whereas in the epidermis, only knockdown of utx-1 conferred improved longevity. Conclusions We show that the regulation of longevity by chromatin modifiers can be the result of the interaction between distinct factors, such as the level and tissue of expression. Overall, we suggest that the heterochromatin loss model of ageing may be too simplistic an explanation of organismal ageing when molecular and tissue-specific effects are taken into account.

Transcriptional targets of DAF-16 insulin signaling pathway protect C. elegans from extreme hypertonic stress

2005 ◽  
Vol 288 (2) ◽  
pp. C467-C474 ◽  
Author(s):  
S. Todd Lamitina ◽  
Kevin Strange
Keyword(s):  
Insulin Signaling ◽  
Stress Resistance ◽  
Molecular Mechanisms ◽  
Organic Osmolytes ◽  
Dependent Manner ◽  
Animal Cells ◽  
Hypertonic Stress ◽  
C Elegans ◽  
Downstream Target ◽  
Molecular Damage

All cells adapt to hypertonic stress by regulating their volume after shrinkage, by accumulating organic osmolytes, and by activating mechanisms that protect against and repair hypertonicity-induced damage. In mammals and nematodes, inhibition of signaling from the DAF-2/IGF-1 insulin receptor activates the DAF-16/FOXO transcription factor, resulting in increased life span and resistance to some types of stress. We tested the hypothesis that inhibition of insulin signaling in Caenorhabditis elegans also increases hypertonic stress resistance. Genetic inhibition of DAF-2 or its downstream target, the AGE-1 phosphatidylinositol 3-kinase, confers striking resistance to a normally lethal hypertonic shock in a DAF-16-dependent manner. However, insulin signaling is not inhibited by or required for adaptation to hypertonic conditions. Microarray studies have identified 263 genes that are transcriptionally upregulated by DAF-16 activation. We identified 14 DAF-16-upregulated genes by RNA interference screening that are required for age- 1 hypertonic stress resistance. These genes encode heat shock proteins, proteins of unknown function, and trehalose synthesis enzymes. Trehalose levels were elevated approximately twofold in age- 1 mutants, but this increase was insufficient to prevent rapid hypertonic shrinkage. However, age- 1 animals unable to synthesize trehalose survive poorly under hypertonic conditions. We conclude that increased expression of proteins that protect eukaryotic cells against environmental stress and/or repair stress-induced molecular damage confers hypertonic stress resistance in C. elegans daf- 2/ age- 1 mutants. Elevated levels of solutes such as trehalose may also function in a cytoprotective manner. Our studies provide novel insights into stress resistance in animal cells and a foundation for new studies aimed at defining molecular mechanisms underlying these essential processes.

Establishment of gut fate in the E lineage of C. elegans: the roles of lineage-dependent mechanisms and cell interactions

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1267-1277 ◽  
Author(s):  
B. Goldstein
Keyword(s):  
Cell Interactions ◽  
The Other ◽  
Cell Contact ◽  
Cell Stage ◽  
C Elegans ◽  
Daughter Cells ◽  
Intact Embryo ◽  
A Cell ◽  
Random Position ◽  
Recombination Experiments

The gut of C. elegans derives from all the progeny of the E blastomere, a cell of the eight cell stage. Previous work has shown that gut specification requires an induction during the four cell stage (Goldstein, B. (1992) Nature 357, 255–257). Blastomere isolation and recombination experiments were done to determine which parts of the embryo can respond to gut induction. Normally only the posterior side of the EMS blastomere contacts the inducing cell, P2. When P2 was instead placed in a random position on an isolated EMS, gut consistently differentiated from the daughter of EMS contacting P2, indicating that any side of EMS can respond to gut induction. Additionally, moving P2 around to the opposite side of EMS in an otherwise intact embryo caused EMS's two daughter cells to switch lineage timings, and gut to differentiate from the descendents of what normally would be the MS blastomere. The other cells of the four cell stage, ABa, ABp, and P2, did not form gut when placed in contact with the inducer. To determine whether any other inductions are involved in gut specification, timed blastomere isolations were done at the two and eight cell stages. In the absence of cell contact at the two cell stage, segregation of gut fate proceeded normally at both the two and four cell stages. Gut fate also segregated properly in the absence of cell contact at the eight cell stage. A model is presented for the roles of lineage-dependent mechanisms and cell interactions in establishing gut fate in the E lineage.

scholarly journals PCMD-1 bridges the centrioles and the PCM scaffold in C. elegans

2020 ◽  
Author(s):  
Lisa Stenzel ◽  
Judith Mehler ◽  
Alina Schreiner ◽  
Sim Üstüner ◽  
Elisa Zuccoli ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Coiled Coil ◽  
Protein Protein Interactions ◽  
Animal Cells ◽  
C Elegans ◽  
Mitotic Kinase ◽  
Spindle Poles ◽  
Pericentriolar Material ◽  
Translocation Assay ◽  
Assembly Proteins

ABSTRACTCorrect cell division relies on the formation of a bipolar spindle. In animal cells, microtubule nucleation at the spindle poles is facilitated by the pericentriolar material (PCM), which assembles around a pair of centrioles. Although centrioles are essential for PCM assembly, proteins that anchor the PCM to the centrioles are less known. Here we investigate the molecular function of PCMD-1 in bridging the PCM and the centrioles in Caenorhabditis elegans.We demonstrate that centrosomal recruitment of PCMD-1 is dependent on the outer centriolar protein SAS-7. While the most C-terminal part of PCMD-1 is sufficient to target it to the centrosome, the coiled-coil domain promotes its accumulation by facilitating self-interaction. We reveal that PCMD-1 is bridging the centrioles and PCM scaffold through protein-protein interactions with the PCM scaffold protein SPD-5, the mitotic kinase PLK-1 and the centriolar protein SAS-4. Using an ectopic translocation assay, we show that PCMD-1 is able to selectively recruit downstream PCM scaffold components to an ectopic location in the cell, indicating that PCMD-1 is sufficient to anchor the PCM scaffold proteins to the centrioles. Our work suggests that PCMD-1 is an essential functional bridge between the centrioles and the PCM.

scholarly journals Functional oscillation of a multienzyme glucosome assembly during cell cycle progression

2022 ◽  
Author(s):  
Miji Jeon ◽  
Danielle L Schmitt ◽  
Minjoung Kyoung ◽  
Songon An
Keyword(s):  
Cell Cycle ◽  
Glucose Metabolism ◽  
Single Cell ◽  
Cell Biology ◽  
Cell Cycle Progression ◽  
Metabolic Adaptation ◽  
Dependent Manner ◽  
Cycle Progression ◽  
Size Dependent ◽  
A Cell

Glucose metabolism has been studied extensively to understand functional interplays between metabolism and a cell cycle. However, our understanding of cell cycle-dependent metabolic adaptation particularly in human cells remains largely elusive. Meanwhile, human enzymes in glucose metabolism are shown to functionally organize into three different sizes of a multienzyme metabolic assembly, the glucosome, to regulate glucose flux in a size-dependent manner. Here, using fluorescence single-cell imaging techniques, we discover that glucosomes spatiotemporally oscillate during a cell cycle in an assembly size-dependent manner. Importantly, their oscillation at single-cell levels is in accordance with functional contributions of glucose metabolism to cell cycle progression at a population level. Collectively, we demonstrate functional oscillation of glucosomes during cell cycle progression and thus their biological significance to human cell biology.

Interactions of different vegetal cells with mesomeres during early stages of sea urchin development

Development ◽  
1991 ◽  
Vol 112 (3) ◽  
pp. 881-890 ◽  
Author(s):  
O. Khaner ◽  
F. Wilt
Keyword(s):  
Sea Urchin ◽  
Normal Development ◽  
Pigment Cells ◽  
Regional Differentiation ◽  
Cell Type ◽  
Animal Cells ◽  
Cell Stage ◽  
Latent Ability ◽  
A Cell ◽  
Poorly Differentiated

It has been known from results obtained in the classical experiments on sea urchin embryos that cell isolation and transplantation showed extensive interactions between the early blastomeres and/or their descendants. In the experiments reported here a systematic reexamination of recombination of mesomeres and their progeny (which come from the animal hemisphere) with various vegetal cells derived from blastomeres of the 32- and 64-cell stage was carried out. Cells were marked with lineage tracers to follow which cell gave rise to what structures, and newly available molecular markers have been used to analyze different structures characteristic of regional differentiation. Large micromeres form spicules and induce gut and pigment cells in mesomeres, conforming to previous results. Small micromeres, a cell type not heretofore examined, gave rise to no recognizable structure and had very limited ability to evoke poorly differentiated gut tissue in mesomeres. Macromeres and their descendants, Veg 1 and Veg 2, form primarily what their normal fate dictated, though both did have some capacity to form spicules, presumably by formation from secondary mesenchyme. Macromeres and their descendants were not potent inducers of vegetal structures in animal cells, but they suppress the latent ability of mesomeres to form vegetal structures. The results lead us to propose that the significant interactions during normal development may be principally suppressive effects of mesomeres on one another and of adjacent vegetal cells on mesomeres.

scholarly journals M-phase-specific phosphorylation of the POU transcription factor GHF-1 by a cell cycle-regulated protein kinase inhibits DNA binding.

1995 ◽  
Vol 15 (12) ◽  
pp. 6694-6701 ◽  
Author(s):  
C Caelles ◽  
H Hennemann ◽  
M Karin
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Dna Binding ◽  
Binding Activity ◽  
Dependent Manner ◽  
Mitotic Kinase ◽  
Dna Binding Activity ◽  
M Phase ◽  
A Cell

GHF-1 is a member of the POU family of homeodomain proteins. It is a cell-type-specific transcription factor responsible for determination and expansion of growth hormone (GH)- and prolactin-expressing cells in the anterior pituitary. It was previously suggested that cyclic AMP (cAMP)-responsive protein kinase A (PKA) phosphorylates GHF-1 at a site within the N-terminal arm of its homeodomain, thereby inhibiting its binding to the GH promoter. These results, however, are inconsistent with the physiological stimulation of GH production by the cAMP pathway. As reported here, cAMP agonists and PKA do not inhibit GHF-1 activity in living cells and although they stimulate the phosphorylation of GHF-1, the inhibitory phosphoacceptor site within the homeodomain is not affected. Instead, this site, Thr-220, is subject to M-phase-specific phosphorylation. As a result, GHF-1 DNA binding activity is transiently inhibited during the M phase. This activity is regained once cells enter G1, a phase during which GHF-1 phosphorylation is minimal. Thr-220 of GHF-1 is the homolog of the mitotic phosphoacceptor site responsible for the M-phase-specific inhibition of Oct-1 DNA binding Ser-382. As this site is conserved in all POU proteins, it appears that all members of this group are similarly regulated. A specific kinase activity distinct in its substrate specificity and susceptibility to inhibitors from the Cdc2 mitotic kinase or PKA was identified in extracts of mitotic cells. This novel activity could be involved in regulating the DNA binding activity of all POU proteins in a cell cycle-dependent manner.

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