Faculty Opinions recommendation of Wnt/Frizzled signaling controls C. elegans gastrulation by activating actomyosin contractility.

2006 ◽  
Author(s):  
Morris Maduro
Keyword(s):  
C Elegans ◽  
Actomyosin Contractility

scholarly journals Novel cytokinetic ring components drive negative feedback in cortical contractility

2019 ◽  
Author(s):  
Kathryn Rehain Bell ◽  
Michael E. Werner ◽  
Anusha Doshi ◽  
Daniel B. Cortes ◽  
Adam Sattler ◽  
...  
Keyword(s):  
Negative Feedback ◽  
Feedback Loop ◽  
Small Gtpase ◽  
Negative Feedback Loop ◽  
Cavernous Malformations ◽  
C Elegans ◽  
Rhoa Activity ◽  
Actomyosin Contractility ◽  
Cortical Contractility ◽  
Muscle Myosin

AbstractActomyosin cortical contractility drives many cell shape changes including cytokinetic furrowing. While positive regulation of contractility is well characterized, counterbalancing negative regulation and mechanical brakes are less well understood. The small GTPase RhoA is a central regulator, activating cortical actomyosin contractility during cytokinesis and other events. Here we report how two novel cytokinetic ring components, GCK-1 and CCM-3, participate in a negative feedback loop among RhoA and its cytoskeletal effectors to inhibit contractility. GCK-1 and CCM-3 are recruited by active RhoA and anillin to the cytokinetic ring, where they in turn limit RhoA activity and contractility. This is evidenced by increased RhoA activity, anillin and non-muscle myosin II in the cytokinetic ring, and faster cytokinetic furrowing, following depletion of GCK-1 or CCM-3. GCK-1 or CCM-3 depletion also reduced RGA-3 levels in pulses, and increased baseline RhoA activity and pulsed contractility during zygote polarization. Together, our findings suggest that GCK-1 and CCM-3 regulate cortical actomyosin contractility via negative feedback.SummaryNovel cytokinetic ring proteins, the Ste20 family kinase GCK-1 and its heterodimeric cofactor Cerebral Cavernous Malformations-3, close a negative feedback loop involving the RhoA GAP RGA-3/4, RhoA, and its cytoskeletal effector anillin to limit actomyosin contractility in cytokinesis and during polarization of the C. elegans zygote.

scholarly journals Actin capping protein regulates actomyosin contractility to maintain germline architecture in C. elegans

2021 ◽  
Author(s):  
Shinjini Ray ◽  
Priti Agarwal ◽  
Ronen Zaidel-Bar
Keyword(s):  
Physiological Role ◽  
Fold Increase ◽  
Actin Dynamics ◽  
Structural Defects ◽  
Capping Protein ◽  
C Elegans ◽  
Actomyosin Contractility ◽  
Actin Capping Protein ◽  
Actin Capping

Actin dynamics play an important role in the morphogenesis of cells and tissues, yet the control of actin filament growth takes place at the molecular level. A challenge in the field is to link the molecular function of actin regulators with their physiological function. Here, we report the in vivo role of the actin capping protein CAP-1 in the C. elegans germline. We show that CAP-1 is associated with actomyosin structures in the cortex and rachis, where it keeps the level of contractility in check. A 60% reduction in the level of CAP-1 leads to a 2-fold increase in F-actin and non-muscle myosin II and only a 30% increase in Arp2/3. CAP-1 depletion leads to severe structural defects in the syncytial germline and oocytes, which can be rescued by reducing myosin activity. Thus, we uncover a physiological role for actin capping protein in maintaining C. elegans fertility by regulating the level of actomyosin contractility.

scholarly journals Wnt/Frizzled Signaling Controls C. elegans Gastrulation by Activating Actomyosin Contractility

2006 ◽  
Vol 16 (20) ◽  
pp. 1986-1997 ◽  
Author(s):  
Jen-Yi Lee ◽  
Daniel J. Marston ◽  
Timothy Walston ◽  
Jeff Hardin ◽  
Ari Halberstadt ◽  
...  
Keyword(s):  
C Elegans ◽  
Actomyosin Contractility

scholarly journals Actomyosin contractility regulators stabilize the cytoplasmic bridge between the two primordial germ cells during Caenorhabditis elegans embryogenesis

2017 ◽  
Vol 28 (26) ◽  
pp. 3789-3800 ◽  
Author(s):  
Eugénie Goupil ◽  
Rana Amini ◽  
David H. Hall ◽  
Jean-Claude Labbé
Keyword(s):  
Caenorhabditis Elegans ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Cytoplasmic Bridge ◽  
C Elegans ◽  
Daughter Cells ◽  
Actomyosin Contractility ◽  
Nonmuscle Myosin Ii ◽  
Cytoplasmic Bridges ◽  
Key Steps

Stable cytoplasmic bridges arise from failed cytokinesis, the last step of cell division, and are a key feature of syncytial architectures in the germline of most metazoans. Whereas the Caenorhabditis elegans germline is syncytial, its formation remains poorly understood. We found that the germline precursor blastomere, P4, fails cytokinesis, leaving a stable cytoplasmic bridge between the two daughter cells, Z2 and Z3. Depletion of several regulators of actomyosin contractility resulted in a regression of the membrane partition between Z2 and Z3, indicating that they are required to stabilize the cytoplasmic bridge. Epistatic analysis revealed a pathway in which Rho regulators promote accumulation of the noncannonical anillin ANI-2 at the stable cytoplasmic bridge, which in turns promotes the accumulation of the nonmuscle myosin II NMY-2 and the midbody component CYK-7 at the bridge, in part by limiting the accumulation of canonical anillin ANI-1. Our results uncover key steps in C. elegans germline formation and define a set of conserved regulators that are enriched at the primordial germ cell cytoplasmic bridge to ensure its stability during embryonic development.

scholarly journals Excitable RhoA dynamics drive pulsed contractions in the early C. elegans embryo

2018 ◽  
Vol 217 (12) ◽  
pp. 4230-4252 ◽  
Author(s):  
Jonathan B. Michaux ◽  
François B. Robin ◽  
William M. McFadden ◽  
Edwin M. Munro
Keyword(s):  
Mathematical Model ◽  
Local Control ◽  
Quantitative Imaging ◽  
Myosin Ii ◽  
C Elegans ◽  
Gtpase Activating Proteins ◽  
Actomyosin Contractility ◽  
Rhoa Gtpase ◽  
Genetic Perturbations ◽  
Underlying Mechanisms

Pulsed actomyosin contractility underlies diverse modes of tissue morphogenesis, but the underlying mechanisms remain poorly understood. Here, we combined quantitative imaging with genetic perturbations to identify a core mechanism for pulsed contractility in early Caenorhabditis elegans embryos. We show that pulsed accumulation of actomyosin is governed by local control of assembly and disassembly downstream of RhoA. Pulsed activation and inactivation of RhoA precede, respectively, the accumulation and disappearance of actomyosin and persist in the absence of Myosin II. We find that fast (likely indirect) autoactivation of RhoA drives pulse initiation, while delayed, F-actin–dependent accumulation of the RhoA GTPase-activating proteins RGA-3/4 provides negative feedback to terminate each pulse. A mathematical model, constrained by our data, suggests that this combination of feedbacks is tuned to generate locally excitable RhoA dynamics. We propose that excitable RhoA dynamics are a common driver for pulsed contractility that can be tuned or coupled differently to actomyosin dynamics to produce a diversity of morphogenetic outcomes.

scholarly journals Excitable RhoA dynamics drive pulsed contractions in the early C. elegans embryo

2016 ◽  
Author(s):  
Jonathan B. Michaux ◽  
François B. Robin ◽  
William M. McFadden ◽  
Edwin M. Munro
Keyword(s):  
Mathematical Model ◽  
Quantitative Imaging ◽  
Myosin Ii ◽  
C Elegans ◽  
Rhoa Activation ◽  
Gtpase Activating Proteins ◽  
Actomyosin Contractility ◽  
Rhoa Gtpase ◽  
Genetic Perturbations ◽  
Underlying Mechanisms

AbstractPulsed actomyosin contractility underlies diverse modes of tissue morphogenesis, but the underlying mechanisms remain poorly understood. Here, we combine quantitative imaging with genetic perturbations to identify a core mechanism for pulsed contractility in early C. elegans embryos. We show that pulsed accumulation of actomyosin is governed by local control of assembly and disassembly downstream of RhoA. Pulsed activation and inactivation of RhoA precede, respectively, accumulation and disappearance of actomyosin, and persist in the nearly complete absence of Myosin II. We find that fast positive feedback on RhoA activation drives pulse initiation, while F-actin dependent accumulation of the RhoA GTPase activating proteins (GAPs) RGA-3/4 provides delayed negative feedback to terminate each pulse. An experimentally constrained mathematical model confirms that in principle these feedbacks are sufficient to generate locally excitable RhoA dynamics. We propose that excitable RhoA dynamics are a common driver for pulsed contractility that can be differently tuned or coupled to actomyosin dynamics to produce a diversity of morphogenetic outcomes.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

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