scholarly journals TGFβ-like DAF-7 acts as a systemic signal for autophagy regulation in C. elegans

2019 ◽  
Vol 218 (12) ◽  
pp. 3998-4006 ◽  
Author(s):  
Yujie Zhang ◽  
Linxiang Qi ◽  
Hong Zhang
Keyword(s):  
Tgfβ Signaling ◽  
Animal Development ◽  
C Elegans ◽  
Systemic Factor ◽  
Systemic Signal ◽  
Response To Stress ◽  
Specific Pair ◽  
Multicellular Organisms ◽  
Autophagy Activity ◽  
Ciliated Neurons

In response to stress conditions, autophagy activity in multicellular organisms is systemically modulated to ensure maintenance of cellular homeostasis at an organismal level. Very little is known about the intercellular signals that elicit the long-range organism-wide autophagy response. Here we showed that during Caenorhabditis elegans development, loss of cuticle annular furrow collagens elicits autophagy in the hypodermis, intestine, and muscle. The cilia of sensory neurons with cuticle-localized endings are essential for triggering this systemic response. The TGFβ-like molecule DAF-7, which is secreted in part from a specific pair of ciliated neurons, acts as a systemic factor that activates a canonical TGFβ signaling pathway in distant tissues to induce autophagy. We also showed that AAK-2/AMPK and the STAT-like protein STA-2 act differentially in different tissues for autophagy activation. Our study reveals a circuit that senses and transduces the signal from the damaged cuticle to activate systemic autophagy during animal development.

scholarly journals The secreted endoribonuclease ENDU-2 from the soma protects germline immortality in C. elegans

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjing Qi ◽  
Erika D. V. Gromoff ◽  
Fan Xu ◽  
Qian Zhao ◽  
Wei Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cell ◽  
Small Rnas ◽  
C Elegans ◽  
Cleavage Activity ◽  
Response To Temperature ◽  
Multicellular Organisms ◽  
Cell Immortality ◽  
Mature Mrnas ◽  
Endoribonuclease Activity

AbstractMulticellular organisms coordinate tissue specific responses to environmental information via both cell-autonomous and non-autonomous mechanisms. In addition to secreted ligands, recent reports implicated release of small RNAs in regulating gene expression across tissue boundaries. Here, we show that the conserved poly-U specific endoribonuclease ENDU-2 in C. elegans is secreted from the soma and taken-up by the germline to ensure germline immortality at elevated temperature. ENDU-2 binds to mature mRNAs and negatively regulates mRNA abundance both in the soma and the germline. While ENDU-2 promotes RNA decay in the soma directly via its endoribonuclease activity, ENDU-2 prevents misexpression of soma-specific genes in the germline and preserves germline immortality independent of its RNA-cleavage activity. In summary, our results suggest that the secreted RNase ENDU-2 regulates gene expression across tissue boundaries in response to temperature alterations and contributes to maintenance of stem cell immortality, probably via retaining a stem cell specific program of gene expression.

Context-specific regulation of lysosomal lipolysis through network-level diverting of transcription factor interactions

2021 ◽  
Vol 118 (41) ◽  
pp. e2104832118
Author(s):  
Vinod K. Mony ◽  
Anna Drangowska-Way ◽  
Reka Albert ◽  
Emma Harrison ◽  
Abbas Ghaddar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Target Gene ◽  
Specific Nature ◽  
C Elegans ◽  
Functional Interactions ◽  
Genetic Epistasis ◽  
Specific Regulation ◽  
Context Specific ◽  
Factor Interactions ◽  
Multicellular Organisms

Plasticity in multicellular organisms involves signaling pathways converting contexts—either natural environmental challenges or laboratory perturbations—into context-specific changes in gene expression. Congruently, the interactions between the signaling molecules and transcription factors (TF) regulating these responses are also context specific. However, when a target gene responds across contexts, the upstream TF identified in one context is often inferred to regulate it across contexts. Reconciling these stable TF–target gene pair inferences with the context-specific nature of homeostatic responses is therefore needed. The induction of the Caenorhabditis elegans genes lipl-3 and lipl-4 is observed in many genetic contexts and is essential to survival during fasting. We find DAF-16/FOXO mediating lipl-4 induction in all contexts tested; hence, lipl-4 regulation seems context independent and compatible with across-context inferences. In contrast, DAF-16–mediated regulation of lipl-3 is context specific. DAF-16 reduces the induction of lipl-3 during fasting, yet it promotes it during oxidative stress. Through discrete dynamic modeling and genetic epistasis, we define that DAF-16 represses HLH-30/TFEB—the main TF activating lipl-3 during fasting. Contrastingly, DAF-16 activates the stress-responsive TF HSF-1 during oxidative stress, which promotes C. elegans survival through induction of lipl-3. Furthermore, the TF MXL-3 contributes to the dominance of HSF-1 at the expense of HLH-30 during oxidative stress but not during fasting. This study shows how context-specific diverting of functional interactions within a molecular network allows cells to specifically respond to a large number of contexts with a limited number of molecular players, a mode of transcriptional regulation we name “contextualized transcription.”

scholarly journals pop-1/TCF, ref-2/ZIC and T-box factors regulate the development of anterior cells in the C. elegans embryo

2021 ◽  
Author(s):  
Jonathan D Rumley ◽  
Elicia A Preston ◽  
Dylan Cook ◽  
Felicia L Peng ◽  
Amanda L Zacharias ◽  
...  
Keyword(s):  
Wnt Pathway ◽  
Expression Patterns ◽  
Specific Expression ◽  
T Box ◽  
Animal Development ◽  
C Elegans ◽  
The Many ◽  
Necessary And Sufficient ◽  
Cell Division Timing ◽  
Anterior Posterior

Patterning of the anterior-posterior axis is fundamental to animal development. The Wnt pathway plays a major role in this process by activating the expression of posterior genes in animals from worms to humans. This observation raises the question of whether the Wnt pathway or other regulators control the expression of the many anterior-expressed genes. We found that the expression of five anterior-specific genes in Caenorhabditis elegans embryos depends on the Wnt pathway effectors pop-1/TCF and sys-1/β-catenin. We focused further on one of these anterior genes, ref-2/ZIC, a conserved transcription factor expressed in multiple anterior lineages. Live imaging of ref-2 mutant embryos identified defects in cell division timing and position in anterior lineages. Cis-regulatory dissection identified three ref-2 transcriptional enhancers, one of which is necessary and sufficient for anterior-specific expression. This enhancer is activated by the T-box transcription factors TBX-37 and TBX-38, and surprisingly, concatemerized TBX-37/38 binding sites are sufficient to drive anterior-biased expression alone, despite the broad expression of TBX-37 and TBX-38. Taken together, our results highlight the diverse mechanisms used to regulate anterior expression patterns in the embryo.

scholarly journals Apoptosis, guardian of the genome: Review

2021 ◽  
Vol 5 (1) ◽  
pp. 037-054
Author(s):  
Ahmad Mohammad Khalil
Keyword(s):  
Cell Death ◽  
Growth And Development ◽  
Scientific Community ◽  
Direct Result ◽  
Life And Death ◽  
Cellular Events ◽  
Response To Stress ◽  
Biochemical Mechanisms ◽  
Number Of Publications ◽  
Multicellular Organisms

Apoptosis has attracted great attention in the last two decades and the number of publications related to apoptosis has been growing exponentially. The revolution that has occurred in apoptosis research is a direct result of a better understanding of the genetic program and biochemical mechanisms of apoptosis. Apoptosis is not only a common normal event but also essential for the growth and development of organisms. In the adult, apoptosis is mostly abnormal, but in its absence or failure cancer cells obtain immortality by escaping this type of cell death. Apoptosis works synergistically in intrinsic and extrinsic pathways. The first pathway is initiated by the cell itself in response to stress. The second is initiated via death receptors stimulated by cells of the immune system. This review is an attempt to answer questions like: Why is cell death important to study? How cells undergo apoptosis? What controls the decision between life and death? Which cellular events could cause the control of apoptosis to be impaired? The literature cited below shows some sort of unity in the scientific community on the necessity of a sophisticated balance between “pro-survival” and “pro-death” forces to ensure the happiness of cells in multicellular organisms

scholarly journals Recent Findings of the Types of Programmed Cell Death

2017 ◽  
Vol 5 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Sylwia Borys ◽  
Ronza Khozmi ◽  
Wiesława Kranc ◽  
Artur Bryja ◽  
Marta Dyszkiewicz-Konwińska ◽  
...  
Keyword(s):  
Cell Death ◽  
Membrane Receptors ◽  
Stress Factors ◽  
Mitotic Catastrophe ◽  
Death Domain ◽  
Apoptotic Pathway ◽  
Response To Stress ◽  
Multicellular Organisms ◽  
Different Characteristics ◽  
Apoptosis And Necrosis

Summary Cell death plays an important role in maintaining the homeostasis of multicellular organisms. It can occur in a controlled manner by apoptosis or autophagy. Cell death which occurs regardless of regulatory factors include necrosis, mitotic catastrophe or oncosis. Apoptosis and necrosis are cellular process that leads to cell death. However their mechanisms are different, although factors triggering them can be similar. Necrosis and apoptosis have many different characteristics in terms of biochemistry and morphology. There are two main pathways of apoptosis induction signal: receptor - dependent and mitochondrial. The outsider apoptotic pathway is induced by external factors stimulating membrane receptors having an intracellular domain called death domain. Mitochondrial apoptotic pathway is activated by increased concentration of reactive oxygen species (ROS), DNA damage, disorders electrolyte transport and an increase in the concentration of the calcium ions in the cytoplasm. In response to stress-factors, mitochondrial channels are opened, so that is released into the cytoplasm cytochrome C. This work is aimed at an overall description of exchanged processes.

scholarly journals Microtubule-dependent ribosome localization in C. elegans neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Kentaro Noma ◽  
Alexandr Goncharov ◽  
Mark H Ellisman ◽  
Yishi Jin
Keyword(s):  
Cell Biology ◽  
Neuronal Development ◽  
Ultrastructural Level ◽  
Synthesis Methods ◽  
Tissue Specific ◽  
C Elegans ◽  
Multicellular Organisms ◽  
Axonal Trafficking ◽  
Insight Into

Subcellular localization of ribosomes defines the location and capacity for protein synthesis. Methods for in vivo visualizing ribosomes in multicellular organisms are desirable in mechanistic investigations of the cell biology of ribosome dynamics. Here, we developed an approach using split GFP for tissue-specific visualization of ribosomes in Caenorhabditis elegans. Labeled ribosomes are detected as fluorescent puncta in the axons and synaptic terminals of specific neuron types, correlating with ribosome distribution at the ultrastructural level. We found that axonal ribosomes change localization during neuronal development and after axonal injury. By examining mutants affecting axonal trafficking and performing a forward genetic screen, we showed that the microtubule cytoskeleton and the JIP3 protein UNC-16 exert distinct effects on localization of axonal and somatic ribosomes. Our data demonstrate the utility of tissue-specific visualization of ribosomes in vivo, and provide insight into the mechanisms of active regulation of ribosome localization in neurons.

A Dynamic Body Model of the NematodeC. eleganswith Neural Oscillators

2005 ◽  
Vol 17 (3) ◽  
pp. 318-326 ◽  
Author(s):  
Michiyo Suzuki ◽  
◽  
Takeshi Goto ◽  
Toshio Tsuji ◽  
Hisao Ohtake ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Motor Control ◽  
Caenorhabditis Elegans ◽  
Neural Circuit ◽  
Rhythmic Movement ◽  
Circuit Model ◽  
Neural Oscillators ◽  
C Elegans ◽  
Body Model ◽  
Multicellular Organisms

The nematode <I>Caenorhabditis elegans (C. elegans)</I>, a relatively simple organism in structure, is one of the most well-studied multicellular organisms. We developed a <I>virtual C. elegans</I> based on the actual organism to analyze motor control. We propose a dynamic body model, including muscles, controlled by a neural circuit model based on the actual nematode. The model uses neural oscillators to generate rhythmic movement. Computer simulation confirmed that the <I>virtual C. elegans</I> realizes motor control similar qualitatively to that of the actual organism. Specified classes of neurons are killed in the neural circuit model corresponding to actual <I>unc</I> mutants, demonstrating that resulting movement of the <I>virtual C. elegans</I> resembles that of actual mutants.

scholarly journals Regulation of the mitosis/meiosis decision in the Caenorhabditis elegans germline

2003 ◽  
Vol 358 (1436) ◽  
pp. 1359-1362 ◽  
Author(s):  
Sarah L. Crittenden ◽  
Christian R. Eckmann ◽  
Liaoteng Wang ◽  
David S. Bernstein ◽  
Marvin Wickens ◽  
...  
Keyword(s):  
Stem Cells ◽  
Caenorhabditis Elegans ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Germline Stem Cells ◽  
Puf Proteins ◽  
C Elegans ◽  
Transcriptional Regulatory ◽  
Mitotic Proliferation ◽  
Multicellular Organisms

During the development of multicellular organisms, the processes of growth and differentiation are kept in balance to generate and maintain tissues and organs of the correct size, shape and cellular composition. We have investigated the molecular controls of growth and differentiation in the Caenorhabditis elegans germline. A single somatic cell, called the distal tip cell, promotes mitotic proliferation in the adjacent germline by GLP–1/Notch signalling. Within the germline, the decisions between mitosis and meiosis and between spermatogenesis and oogenesis are controlled by a group of conserved RNA regulators. FBF, a member of the PUF (for Pumilio and FBF) family of RNA–binding proteins, promotes mitosis by repressing gld–1 mRNA activity; the GLD–1, GLD–2, GLD–3 and NOS–3 proteins promote entry into meiosis by regulating mRNAs that remain unknown. The regulatory balance between opposing FBF and GLD activities is crucial for controlling the extent of germline proliferation. PUF proteins regulate germline stem cells in both Drosophila and C. elegans and are localized to germline stem cells of the mammalian testis. Therefore, this post–transcriptional regulatory switch may be an ancient mechanism for controlling maintenance of stem cells versus differentiation.

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