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Ewe CK, Rechavi O. Natural probiotics improve heritable sterility. EMBO Rep 2023; 24:e58318. [PMID: 37983676 DOI: 10.15252/embr.202358318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 10/18/2023] [Indexed: 11/22/2023] Open
Abstract
Disrupting the small RNA pathway and chromatin-modifying enzymes in C. elegans often leads to a mortal germline (Mrt) phenotype, characterized by progressive sterility observed over multiple generations at elevated temperature. This phenotype arises from the inheritance of aberrant epigenetic memory across generations. In this issue of EMBO Reports, Frézal and colleagues reported that, while in standard laboratory environment C. elegans wild isolates exhibit the Mrt phenotype, sterility does not occur when the worms are exposed to naturally associated bacteria and microsporidia. Excitingly, diet-induced epigenetic memory may persist for multiple generations. This suggests intriguing diet-gene interactions in modulating nongenetic inheritance, potentially shaping the evolutionary trajectory of the animals.
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Affiliation(s)
- Chee Kiang Ewe
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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2
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Flowers S, Kothari R, Torres Cleuren YN, Alcorn MR, Ewe CK, Alok G, Fiallo SL, Joshi PM, Rothman JH. Regulation of defective mitochondrial DNA accumulation and transmission in C. elegans by the programmed cell death and aging pathways. eLife 2023; 12:e79725. [PMID: 37782016 PMCID: PMC10545429 DOI: 10.7554/elife.79725] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 09/15/2023] [Indexed: 10/03/2023] Open
Abstract
The heteroplasmic state of eukaryotic cells allows for cryptic accumulation of defective mitochondrial genomes (mtDNA). 'Purifying selection' mechanisms operate to remove such dysfunctional mtDNAs. We found that activators of programmed cell death (PCD), including the CED-3 and CSP-1 caspases, the BH3-only protein CED-13, and PCD corpse engulfment factors, are required in C. elegans to attenuate germline abundance of a 3.1-kb mtDNA deletion mutation, uaDf5, which is normally stably maintained in heteroplasmy with wildtype mtDNA. In contrast, removal of CED-4/Apaf1 or a mutation in the CED-4-interacting prodomain of CED-3, do not increase accumulation of the defective mtDNA, suggesting induction of a non-canonical germline PCD mechanism or non-apoptotic action of the CED-13/caspase axis. We also found that the abundance of germline mtDNAuaDf5 reproducibly increases with age of the mothers. This effect is transmitted to the offspring of mothers, with only partial intergenerational removal of the defective mtDNA. In mutants with elevated mtDNAuaDf5 levels, this removal is enhanced in older mothers, suggesting an age-dependent mechanism of mtDNA quality control. Indeed, we found that both steady-state and age-dependent accumulation rates of uaDf5 are markedly decreased in long-lived, and increased in short-lived, mutants. These findings reveal that regulators of both PCD and the aging program are required for germline mtDNA quality control and its intergenerational transmission.
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Affiliation(s)
- Sagen Flowers
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Rushali Kothari
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Yamila N Torres Cleuren
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
- Computational Biology Unit, Institute for Informatics, University of BergenBergenNorway
| | - Melissa R Alcorn
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Chee Kiang Ewe
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Geneva Alok
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Samantha L Fiallo
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Pradeep M Joshi
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Joel H Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
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Ewe CK, Rechavi O. The third barrier to transgenerational inheritance in animals: somatic epigenetic resetting. EMBO Rep 2023; 24:e56615. [PMID: 36862326 PMCID: PMC10074133 DOI: 10.15252/embr.202256615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/02/2023] [Accepted: 02/15/2023] [Indexed: 03/03/2023] Open
Abstract
After early controversy, it is now increasingly clear that acquired responses to environmental factors may perpetuate across multiple generations-a phenomenon termed transgenerational epigenetic inheritance (TEI). Experiments with Caenorhabditis elegans, which exhibits robust heritable epigenetic effects, demonstrated small RNAs as key factors of TEI. Here, we discuss three major barriers to TEI in animals, two of which, the "Weismann barrier" and germline epigenetic reprogramming, have been known for decades. These are thought to effectively prevent TEI in mammals but not to the same extent in C. elegans. We argue that a third barrier-that we termed "somatic epigenetic resetting"-may further inhibit TEI and, unlike the other two, restricts TEI in C. elegans as well. While epigenetic information can overcome the Weismann barrier and transmit from the soma to the germline, it usually cannot "travel back" directly from the germline to the soma in subsequent generations. Nevertheless, heritable germline memory may still influence the animal's physiology by indirectly modifying gene expression in somatic tissues.
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Affiliation(s)
- Chee Kiang Ewe
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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Ewe CK, Joshi PM, Rothman JH. Endless Worms Most Beautiful: Current Methods For Using Nematodes To Study Evolutionary Developmental Biology. J Vis Exp 2022. [PMID: 37590519 DOI: 10.3791/64594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023] Open
Affiliation(s)
| | - Pradeep M Joshi
- Department of Molecular, Cellular, Developmental Biology, University of California Santa Barbara
| | - Joel H Rothman
- Department of Molecular, Cellular, Developmental Biology, University of California Santa Barbara
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Ewe CK, Sommermann EM, Kenchel J, Flowers SE, Maduro MF, Joshi PM, Rothman JH. Feedforward regulatory logic controls the specification-to-differentiation transition and terminal cell fate during Caenorhabditis elegans endoderm development. Development 2022; 149:dev200337. [PMID: 35758255 PMCID: PMC10656426 DOI: 10.1242/dev.200337] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 05/13/2022] [Indexed: 11/20/2023]
Abstract
The architecture of gene regulatory networks determines the specificity and fidelity of developmental outcomes. We report that the core regulatory circuitry for endoderm development in Caenorhabditis elegans operates through a transcriptional cascade consisting of six sequentially expressed GATA-type factors that act in a recursive series of interlocked feedforward modules. This structure results in sequential redundancy, in which removal of a single factor or multiple alternate factors in the cascade leads to a mild or no effect on gut development, whereas elimination of any two sequential factors invariably causes a strong phenotype. The phenotypic strength is successfully predicted with a computational model based on the timing and levels of transcriptional states. We found that one factor in the middle of the cascade, END-1, which straddles the distinct events of specification and differentiation, functions in both processes. Finally, we reveal roles for key GATA factors in establishing spatial regulatory state domains by repressing other fates, thereby defining boundaries in the digestive tract. Our findings provide a paradigm that could account for the genetic redundancy observed in many developmental regulatory systems.
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Affiliation(s)
- Chee Kiang Ewe
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Erica M. Sommermann
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Josh Kenchel
- Program in Biomolecular Science and Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA
- Chemical and Biomolecular Engineering Department, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Sagen E. Flowers
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Morris F. Maduro
- Molecular, Cell and Systems Biology Department, University of California Riverside, Riverside, CA 92521, USA
| | - Pradeep M. Joshi
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Joel H. Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
- Program in Biomolecular Science and Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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Ewe CK, Alok G, Rothman JH. Stressful development: integrating endoderm development, stress, and longevity. Dev Biol 2020; 471:34-48. [PMID: 33307045 DOI: 10.1016/j.ydbio.2020.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 10/22/2022]
Abstract
In addition to performing digestion and nutrient absorption, the intestine serves as one of the first barriers to the external environment, crucial for protecting the host from environmental toxins, pathogenic invaders, and other stress inducers. The gene regulatory network (GRN) governing embryonic development of the endoderm and subsequent differentiation and maintenance of the intestine has been well-documented in C. elegans. A key regulatory input that initiates activation of the embryonic GRN for endoderm and mesoderm in this animal is the maternally provided SKN-1 transcription factor, an ortholog of the vertebrate Nrf1 and 2, which, like C. elegans SKN-1, perform conserved regulatory roles in mediating a variety of stress responses across metazoan phylogeny. Other key regulatory factors in early gut development also participate in stress response as well as in innate immunity and aging and longevity. In this review, we discuss the intersection between genetic nodes that mediate endoderm/intestine differentiation and regulation of stress and homeostasis. We also consider how direct signaling from the intestine to the germline, in some cases involving SKN-1, facilitates heritable epigenetic changes, allowing transmission of adaptive stress responses across multiple generations. These connections between regulation of endoderm/intestine development and stress response mechanisms suggest that varying selective pressure exerted on the stress response pathways may influence the architecture of the endoderm GRN, thereby leading to genetic and epigenetic variation in early embryonic GRN regulatory events.
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Affiliation(s)
- Chee Kiang Ewe
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
| | - Geneva Alok
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
| | - Joel H Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA.
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7
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Affiliation(s)
- Chee Kiang Ewe
- Chee Kiang Ewe is a Ph.D. candidate at the University of California, Santa Barbara. Send your career story to
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8
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Ewe CK. How I learned to celebrate my identity as a first-generation, international student. Science 2020. [DOI: 10.1126/science.caredit.abg0913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Ewe CK, Torres Cleuren YN, Rothman JH. Evolution and Developmental System Drift in the Endoderm Gene Regulatory Network of Caenorhabditis and Other Nematodes. Front Cell Dev Biol 2020; 8:170. [PMID: 32258041 PMCID: PMC7093329 DOI: 10.3389/fcell.2020.00170] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/02/2020] [Indexed: 01/17/2023] Open
Abstract
Developmental gene regulatory networks (GRNs) underpin metazoan embryogenesis and have undergone substantial modification to generate the tremendous variety of animal forms present on Earth today. The nematode Caenorhabditis elegans has been a central model for advancing many important discoveries in fundamental mechanistic biology and, more recently, has provided a strong base from which to explore the evolutionary diversification of GRN architecture and developmental processes in other species. In this short review, we will focus on evolutionary diversification of the GRN for the most ancient of the embryonic germ layers, the endoderm. Early embryogenesis diverges considerably across the phylum Nematoda. Notably, while some species deploy regulative development, more derived species, such as C. elegans, exhibit largely mosaic modes of embryogenesis. Despite the relatively similar morphology of the nematode gut across species, widespread variation has been observed in the signaling inputs that initiate the endoderm GRN, an exemplar of developmental system drift (DSD). We will explore how genetic variation in the endoderm GRN helps to drive DSD at both inter- and intraspecies levels, thereby resulting in a robust developmental system. Comparative studies using divergent nematodes promise to unveil the genetic mechanisms controlling developmental plasticity and provide a paradigm for the principles governing evolutionary modification of an embryonic GRN.
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Affiliation(s)
- Chee Kiang Ewe
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| | | | - Joel H. Rothman
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
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Ewe CK, Torres Cleuren Y, Alok G, Rothman J. ICD-1/BTF3 antagonizes SKN-1-mediated endoderm specification in Caenorhabditis elegans. MicroPubl Biol 2019; 2019. [PMID: 32550464 PMCID: PMC7252400 DOI: 10.17912/micropub.biology.000167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- Chee Kiang Ewe
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, CA, USA
| | - Yamila Torres Cleuren
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, CA, USA.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Geneva Alok
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, CA, USA
| | - Joel Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California Santa Barbara, CA, USA
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Torres Cleuren YN, Ewe CK, Chipman KC, Mears ER, Wood CG, Al-Alami CEA, Alcorn MR, Turner TL, Joshi PM, Snell RG, Rothman JH. Extensive intraspecies cryptic variation in an ancient embryonic gene regulatory network. eLife 2019; 8:48220. [PMID: 31414984 PMCID: PMC6754231 DOI: 10.7554/elife.48220] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/15/2019] [Indexed: 12/13/2022] Open
Abstract
Innovations in metazoan development arise from evolutionary modification of gene regulatory networks (GRNs). We report widespread cryptic variation in the requirement for two key regulatory inputs, SKN-1/Nrf2 and MOM-2/Wnt, into the C. elegans endoderm GRN. While some natural isolates show a nearly absolute requirement for these two regulators, in others, most embryos differentiate endoderm in their absence. GWAS and analysis of recombinant inbred lines reveal multiple genetic regions underlying this broad phenotypic variation. We observe a reciprocal trend, in which genomic variants, or knockdown of endoderm regulatory genes, that result in a high SKN-1 requirement often show low MOM-2/Wnt requirement and vice-versa, suggesting that cryptic variation in the endoderm GRN may be tuned by opposing requirements for these two key regulatory inputs. These findings reveal that while the downstream components in the endoderm GRN are common across metazoan phylogeny, initiating regulatory inputs are remarkably plastic even within a single species.
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Affiliation(s)
- Yamila N Torres Cleuren
- Department of MCD Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Chee Kiang Ewe
- Department of MCD Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Kyle C Chipman
- Department of MCD Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Emily R Mears
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Cricket G Wood
- Department of MCD Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | | | - Melissa R Alcorn
- Department of MCD Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Thomas L Turner
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - Pradeep M Joshi
- Department of MCD Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Russell G Snell
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Joel H Rothman
- Department of MCD Biology, University of California, Santa Barbara, Santa Barbara, United States.,School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
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