1
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Fausett SR, Sandjak A, Billard B, Braendle C. Higher-order epistasis shapes natural variation in germ stem cell niche activity. Nat Commun 2023; 14:2824. [PMID: 37198172 DOI: 10.1038/s41467-023-38527-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/05/2023] [Indexed: 05/19/2023] Open
Abstract
To study how natural allelic variation explains quantitative developmental system variation, we characterized natural differences in germ stem cell niche activity, measured as progenitor zone (PZ) size, between two Caenorhabditis elegans isolates. Linkage mapping yielded candidate loci on chromosomes II and V, and we found that the isolate with a smaller PZ size harbours a 148 bp promoter deletion in the Notch ligand, lag-2/Delta, a central signal promoting germ stem cell fate. As predicted, introducing this deletion into the isolate with a large PZ resulted in a smaller PZ size. Unexpectedly, restoring the deleted ancestral sequence in the isolate with a smaller PZ did not increase-but instead further reduced-PZ size. These seemingly contradictory phenotypic effects are explained by epistatic interactions between the lag-2/Delta promoter, the chromosome II locus, and additional background loci. These results provide first insights into the quantitative genetic architecture regulating an animal stem cell system.
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Affiliation(s)
- Sarah R Fausett
- Université Côte d'Azur, CNRS, Inserm, IBV, Nice, France.
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA.
| | - Asma Sandjak
- Université Côte d'Azur, CNRS, Inserm, IBV, Nice, France
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2
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Achache H, Falk R, Lerner N, Beatus T, Tzur YB. Oocyte aging is controlled by mitogen-activated protein kinase signaling. Aging Cell 2021; 20:e13386. [PMID: 34061407 PMCID: PMC8208789 DOI: 10.1111/acel.13386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 03/25/2021] [Accepted: 05/08/2021] [Indexed: 12/11/2022] Open
Abstract
Oogenesis is one of the first processes to fail during aging. In women, most oocytes cannot successfully complete meiotic divisions already during the fourth decade of life. Studies of the nematode Caenorhabditis elegans have uncovered conserved genetic pathways that control lifespan, but our knowledge regarding reproductive aging in worms and humans is limited. Specifically, little is known about germline internal signals that dictate the oogonial biological clock. Here, we report a thorough characterization of the changes in the worm germline during aging. We found that shortly after ovulation halts, germline proliferation declines, while apoptosis continues, leading to a gradual reduction in germ cell numbers. In late aging stages, we observed that meiotic progression is disturbed and crossover designation and DNA double-strand break repair decrease. In addition, we detected a decline in the quality of mature oocytes during aging, as reflected by decreasing size and elongation of interhomolog distance, a phenotype also observed in human oocytes. Many of these altered processes were previously attributed to MAPK signaling variations in young worms. In support of this, we observed changes in activation dynamics of MPK-1 during aging. We therefore tested the hypothesis that MAPK controls oocyte quality in aged worms using both genetic and pharmacological tools. We found that in mutants with high levels of activated MPK-1, oocyte quality deteriorates more rapidly than in wild-type worms, whereas reduction of MPK-1 levels enhances quality. Thus, our data suggest that MAPK signaling controls germline aging and could be used to attenuate the rate of oogenesis quality decline.
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Affiliation(s)
- Hanna Achache
- Department of GeneticsInstitute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
| | - Roni Falk
- Department of GeneticsInstitute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
| | - Noam Lerner
- Department of NeurobiologyThe Institute of Life ScienceThe Hebrew University of JerusalemJerusalemIsrael
- The Alexander Grass Center for BioengineeringThe Rachel and Selim Benin School of Computer Science and EngineeringThe Hebrew University of JerusalemJerusalemIsrael
| | - Tsevi Beatus
- Department of NeurobiologyThe Institute of Life ScienceThe Hebrew University of JerusalemJerusalemIsrael
- The Alexander Grass Center for BioengineeringThe Rachel and Selim Benin School of Computer Science and EngineeringThe Hebrew University of JerusalemJerusalemIsrael
| | - Yonatan B. Tzur
- Department of GeneticsInstitute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
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3
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Almanzar DE, Gordon SG, Rog O. Meiotic sister chromatid exchanges are rare in C. elegans. Curr Biol 2021; 31:1499-1507.e3. [PMID: 33740426 PMCID: PMC8051885 DOI: 10.1016/j.cub.2020.11.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/08/2020] [Accepted: 11/05/2020] [Indexed: 11/16/2022]
Abstract
Sexual reproduction shuffles the parental genomes to generate new genetic combinations. To achieve that, the genome is subjected to numerous double-strand breaks, the repair of which involves two crucial decisions: repair pathway and repair template.1 Use of crossover pathways with the homologous chromosome as template exchanges genetic information and directs chromosome segregation. Crossover repair, however, can compromise the integrity of the repair template and is therefore tightly regulated. The extent to which crossover pathways are used during sister-directed repair is unclear because the identical sister chromatids are difficult to distinguish. Nonetheless, indirect assays have led to the suggestion that inter-sister crossovers, or sister chromatid exchanges (SCEs), are quite common.2-11 Here we devised a technique to directly score physiological SCEs in the C. elegans germline using selective sister chromatid labeling with the thymidine analog 5-ethynyl-2'-deoxyuridine (EdU). Surprisingly, we find SCEs to be rare in meiosis, accounting for <2% of repair events. SCEs remain rare even when the homologous chromosome is unavailable, indicating that almost all sister-directed repair is channeled into noncrossover pathways. We identify two mechanisms that limit SCEs. First, SCEs are elevated in the absence of the RecQ helicase BLMHIM-6. Second, the synaptonemal complex-a conserved interface that promotes crossover repair12,13-promotes SCEs when localized between the sisters. Our data suggest that crossover pathways in C. elegans are only used to generate the single necessary link between the homologous chromosomes. Noncrossover pathways repair almost all other breaks, regardless of the repair template.
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Affiliation(s)
- David E Almanzar
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112-0840, USA
| | - Spencer G Gordon
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112-0840, USA
| | - Ofer Rog
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112-0840, USA.
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4
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King SD, Gray CF, Song L, Mittler R, Padilla PA. The mitochondrial localized CISD-3.1/CISD-3.2 proteins are required to maintain normal germline structure and function in Caenorhabditis elegans. PLoS One 2021; 16:e0245174. [PMID: 33544710 PMCID: PMC7864470 DOI: 10.1371/journal.pone.0245174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/22/2020] [Indexed: 11/18/2022] Open
Abstract
Reproductive organs and developing tissues have high energy demands that require metabolic functions primarily supported by mitochondria function. The highly conserved CISD/NEET iron-sulfur (Fe-S) protein family regulates iron and reactive oxygen homeostasis, both of which are important for mitochondrial function. Disruption of iron and reactive oxygen homeostasis typically leads to detrimental effects. In humans, CISD dysfunction is associated with human health issues including Wolfram syndrome 2. Using C. elegans, we previously determined that the cisd-1, cisd-3.1 and cisd-3.2 have an overlapping role in the regulation of physiological germline apoptosis through the canonical programmed cell death pathway. Here, we isolated the cisd-3.2(pnIs68) mutant that resulted in physiological and fitness defects including germline abnormalities that are associated with abnormal stem cell niche and disrupted formation of bivalent chromosomes. The cisd-3.2(pnIs68) mutation led to complete disruption of the cisd-3.2 gene expression and a decrease in expression of genetically intact cisd-1 and cisd-3.1 genes suggesting an indirect impact of the cisd-3.2(pnIs68) allele. The CISD-3.2 and CISD-3.1 proteins localize to the mitochondria in many tissues throughout development. The cisd-3.2(pnIs68) mutant displays phenotypes associated with mitochondrial dysfunction, including disruption of the mitochondrial network within the germline. These results further support the idea that the CISD protein family is required for mitochondrial function that supports important functions in animals including overall fitness and germline viability.
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Affiliation(s)
- Skylar D. King
- Division of Plant Sciences, College of Agriculture, Food and Natural Resources, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
- Department of Surgery, University of Missouri School of Medicine, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
| | - Chipo F. Gray
- Department of Biological Sciences, University of North Texas, Denton, TX, United States of America
| | - Luhua Song
- Department of Biological Sciences, University of North Texas, Denton, TX, United States of America
| | - Ron Mittler
- Division of Plant Sciences, College of Agriculture, Food and Natural Resources, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
- Department of Surgery, University of Missouri School of Medicine, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
| | - Pamela A. Padilla
- Department of Biological Sciences, University of North Texas, Denton, TX, United States of America
- * E-mail:
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5
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Delaney K, Strobino M, Wenda JM, Pankowski A, Steiner FA. H3.3K27M-induced chromatin changes drive ectopic replication through misregulation of the JNK pathway in C. elegans. Nat Commun 2019; 10:2529. [PMID: 31175278 PMCID: PMC6555832 DOI: 10.1038/s41467-019-10404-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 05/10/2019] [Indexed: 12/20/2022] Open
Abstract
Substitution of lysine 27 with methionine in histone H3.3 is a recently discovered driver mutation of pediatric high-grade gliomas. Mutant cells show decreased levels and altered distribution of H3K27 trimethylation (H3K27me3). How these chromatin changes are established genome-wide and lead to tumorigenesis remains unclear. Here we show that H3.3K27M-mediated alterations in H3K27me3 distribution result in ectopic DNA replication and cell cycle progression of germ cells in Caenorhabditis elegans. By genetically inducing changes in the H3.3 distribution, we demonstrate that both H3.3K27M and pre-existing H3K27me3 act locally and antagonistically on Polycomb Repressive Complex 2 (PRC2) in a concentration-dependent manner. The heterochromatin changes result in extensive gene misregulation, and genetic screening identified upregulation of JNK as an underlying cause of the germcell aberrations. Moreover, JNK inhibition suppresses the replicative fate in human tumor-derived H3.3K27M cells, thus establishing C. elegans as a powerful model for the identification of potential drug targets for treatment of H3.3K27M tumors. Substitution of lysine 27 with methionine in histone H3.3 (H3.3K27M) is a driver mutation of pediatric high-grade gliomas. Here the authors show that H3.3K27M-mediated alterations in H3K27me3 distribution result in ectopic DNA replication and cell cycle progression of germ cells in Caenorhabditis elegans, through JNK pathway misregulation.
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Affiliation(s)
- Kamila Delaney
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, University of Geneva, 1211, Geneva, Switzerland
| | - Maude Strobino
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, University of Geneva, 1211, Geneva, Switzerland
| | - Joanna M Wenda
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, University of Geneva, 1211, Geneva, Switzerland
| | - Andrzej Pankowski
- Team of Mathematics and Physics, Faculty of Civil Engineering, Mechanics and Petrochemistry, Warsaw University of Technology, 09-400, Płock, Poland
| | - Florian A Steiner
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, University of Geneva, 1211, Geneva, Switzerland.
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Gutnik S, Thomas Y, Guo Y, Stoecklin J, Neagu A, Pintard L, Merlet J, Ciosk R. PRP-19, a conserved pre-mRNA processing factor and E3 ubiquitin ligase, inhibits the nuclear accumulation of GLP-1/Notch intracellular domain. Biol Open 2018; 7:bio034066. [PMID: 30012553 PMCID: PMC6078339 DOI: 10.1242/bio.034066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/15/2018] [Indexed: 01/13/2023] Open
Abstract
The Notch signalling pathway is a conserved and widespread signalling paradigm, and its misregulation has been implicated in numerous disorders, including cancer. The output of Notch signalling depends on the nuclear accumulation of the Notch receptor intracellular domain (ICD). Using the Caenorhabditis elegans germline, where GLP-1/Notch-mediated signalling is essential for maintaining stem cells, we monitored GLP-1 in vivo We found that the nuclear enrichment of GLP-1 ICD is dynamic: while the ICD is enriched in germ cell nuclei during larval development, it is depleted from the nuclei in adult germlines. We found that this pattern depends on the ubiquitin proteolytic system and the splicing machinery and, identified the splicing factor PRP-19 as a candidate E3 ubiquitin ligase required for the nuclear depletion of GLP-1 ICD.
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Affiliation(s)
- Silvia Gutnik
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Yann Thomas
- Cell Cycle and Development, Institut Jacques Monod, UMR7592 CNRS - Université Paris Diderot, Sorbonne Paris Cité, F-75013 Paris, France
| | - Yanwu Guo
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Janosch Stoecklin
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Anca Neagu
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Lionel Pintard
- Cell Cycle and Development, Institut Jacques Monod, UMR7592 CNRS - Université Paris Diderot, Sorbonne Paris Cité, F-75013 Paris, France
| | - Jorge Merlet
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Developmental Biology Laboratory, UMR 7622, F-75005 Paris, France
| | - Rafal Ciosk
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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7
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Reichman R, Shi Z, Malone R, Smolikove S. Mitotic and Meiotic Functions for the SUMOylation Pathway in the Caenorhabditis elegans Germline. Genetics 2018; 208:1421-1441. [PMID: 29472245 PMCID: PMC5887140 DOI: 10.1534/genetics.118.300787] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/19/2018] [Indexed: 02/07/2023] Open
Abstract
Meiosis is a highly regulated process, partly due to the need to break and then repair DNA as part of the meiotic program. Post-translational modifications are widely used during meiotic events to regulate steps such as protein complex formation, checkpoint activation, and protein attenuation. In this paper, we investigate how proteins that are obligatory components of the SUMO (small ubiquitin-like modifier) pathway, one such post-translational modification, affect the Caenorhabditis elegans germline. We show that UBC-9, the E2 conjugation enzyme, and the C. elegans homolog of SUMO, SMO-1, localize to germline nuclei throughout prophase I. Mutant analysis of smo-1 and ubc-9 revealed increased recombination intermediates throughout the germline, originating during the mitotic divisions. SUMOylation mutants also showed late meiotic defects including defects in the restructuring of oocyte bivalents and endomitotic oocytes. Increased rates of noninterfering crossovers were observed in ubc-9 heterozygotes, even though interfering crossovers were unaffected. We have also identified a physical interaction between UBC-9 and DNA repair protein MRE-11 ubc-9 and mre-11 null mutants exhibited similar phenotypes at germline mitotic nuclei and were synthetically sick. These phenotypes and genetic interactions were specific to MRE-11 null mutants as opposed to RAD-50 or resection-defective MRE-11 We propose that the SUMOylation pathway acts redundantly with MRE-11, and in this process MRE-11 likely plays a structural role.
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Affiliation(s)
- Rachel Reichman
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Zhuoyue Shi
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Robert Malone
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
| | - Sarit Smolikove
- Department of Biology, The University of Iowa, Iowa City, Iowa 52242
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8
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Herbette M, Mercier M, Michal F, Cluet D, Burny C, Yvert G, Robert V, Palladino F. The C. elegans SET-2/SET1 histone H3 Lys4 (H3K4) methyltransferase preserves genome stability in the germline. DNA Repair (Amst) 2017; 57:139-150. [DOI: 10.1016/j.dnarep.2017.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/13/2017] [Accepted: 07/13/2017] [Indexed: 10/19/2022]
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9
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Abstract
The Caenorhabditis elegans germline is an excellent model for studying the regulation of a pool of stem cells and progression of cells from a stem cell state to a differentiated state. At the tissue level, the germline is organized in an assembly line with the germline stem cell (GSC) pool at one end and differentiated cells at the other. A simple mesenchymal niche caps the GSC region of the germline and maintains GSCs in an undifferentiated state by signaling through the conserved Notch pathway. Downstream of Notch signaling, key regulators include novel LST-1 and SYGL-1 proteins and a network of RNA regulatory proteins. In this chapter we present methods for characterizing the C. elegans GSC pool and early germ cell differentiation. The methods include examination of the germline in living and fixed worms, cell cycle analysis, and analysis of markers. We also discuss assays to separate mutants that affect the stem cell vs. differentiation decision from those that affect germ cell processes more generally.
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Affiliation(s)
- Sarah L Crittenden
- HHMI/Department of Biochemistry, Howard Hughes Medical Institute and University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706-1544, USA.
| | - Hannah S Seidel
- HHMI/Department of Biochemistry, Howard Hughes Medical Institute and University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706-1544, USA
| | - Judith Kimble
- HHMI/Department of Biochemistry, Howard Hughes Medical Institute and University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706-1544, USA
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10
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Li Y, Zhang M, Li S, Lv R, Chen P, Liu R, Liang G, Yin L. The Use of the Nematode Caenorhabditis elegans to Evaluate the Adverse Effects of Epoxiconazole Exposure on Spermatogenesis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:E993. [PMID: 27740608 PMCID: PMC5086732 DOI: 10.3390/ijerph13100993] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/20/2016] [Accepted: 09/29/2016] [Indexed: 12/29/2022]
Abstract
There is increasing evidence that epoxiconazole exposure can affect reproductive function, but few studies have investigated adverse effects on spermatogenesis. The nematode Caenorhabditis elegans (C. elegans) was used in our study to assess effects of epoxiconazole on spermatogenesis in male nematodes after 48 h of exposure to concentrations of 0.1, 1.0, or 10.0 μg/L. The results demonstrated that epoxiconazole exposure affected spermatogenesis, decreasing the number of total germ cells, mitotic cells, meiotic cells and spermatids, spermatid diameter, and cross-sectional area, and inducing mitotic germ cell proliferation arrest, premature entry into meiosis, and sperm activation inhibition; however, sperm transfer showed no abnormal changes. In addition, the results showed that epoxiconazole activated the transforming growth factor-β (TGFβ) signaling pathway and increased the expression levels of gene daf-1, daf-3, daf-4, daf-5 and daf-7 in nematodes. We therefore propose that epoxiconazole acts by activating the TGFβ signaling pathway, leading to the impairment of spermatogenesis and the consequent decline in male fertility.
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Affiliation(s)
- Yunhui Li
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Minhui Zhang
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Shaojun Li
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
| | - Rongrong Lv
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Pan Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
| | - Ran Liu
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Geyu Liang
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
| | - Lihong Yin
- Key Laboratory of Environmental Medicine Engineering Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
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11
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Poullet N, Vielle A, Gimond C, Carvalho S, Teotónio H, Braendle C. Complex heterochrony underlies the evolution of Caenorhabditis elegans
hermaphrodite sex allocation. Evolution 2016; 70:2357-2369. [DOI: 10.1111/evo.13032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/30/2016] [Accepted: 08/02/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Nausicaa Poullet
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
| | - Anne Vielle
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
| | - Clotilde Gimond
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
| | - Sara Carvalho
- Instituto Gulbenkian de Ciência; Apartado 14 P-2781-901 Oeiras Portugal
| | - Henrique Teotónio
- Institut de Biologie; École Normale Supérieure; CNRS UMR 8197, INSERM U1024 F-75005 Paris France
| | - Christian Braendle
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
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12
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Hall BA, Piterman N, Hajnal A, Fisher J. Emergent stem cell homeostasis in the C. elegans germline is revealed by hybrid modeling. Biophys J 2016. [PMID: 26200879 PMCID: PMC4621618 DOI: 10.1016/j.bpj.2015.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The establishment of homeostasis among cell growth, differentiation, and apoptosis is of key importance for organogenesis. Stem cells respond to temporally and spatially regulated signals by switching from mitotic proliferation to asymmetric cell division and differentiation. Executable computer models of signaling pathways can accurately reproduce a wide range of biological phenomena by reducing detailed chemical kinetics to a discrete, finite form. Moreover, coordinated cell movements and physical cell-cell interactions are required for the formation of three-dimensional structures that are the building blocks of organs. To capture all these aspects, we have developed a hybrid executable/physical model describing stem cell proliferation, differentiation, and homeostasis in the Caenorhabditis elegans germline. Using this hybrid model, we are able to track cell lineages and dynamic cell movements during germ cell differentiation. We further show how apoptosis regulates germ cell homeostasis in the gonad, and propose a role for intercellular pressure in developmental control. Finally, we use the model to demonstrate how an executable model can be developed from the hybrid system, identifying a mechanism that ensures invariance in fate patterns in the presence of instability.
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Affiliation(s)
- Benjamin A Hall
- Medical Research Council Cancer Unit, Hutchison/Medical Research Council Research Centre, University of Cambridge, Cambridge, United Kingdom; Microsoft Research Cambridge, Cambridge, UK.
| | - Nir Piterman
- Department of Computer Science, University of Leicester, Leicester, UK
| | - Alex Hajnal
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Jasmin Fisher
- Microsoft Research Cambridge, Cambridge, UK; Department of Biochemistry, University of Cambridge, Cambridge, UK.
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13
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Poullet N, Vielle A, Gimond C, Ferrari C, Braendle C. Evolutionarily divergent thermal sensitivity of germline development and fertility in hermaphroditicCaenorhabditisnematodes. Evol Dev 2015; 17:380-97. [DOI: 10.1111/ede.12170] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Nausicaa Poullet
- Institut de Biologie Valrose, CNRS UMR7277; Parc Valrose; 06108 Nice cedex 02 France
- Université Nice Sophia Antipolis; UFR Sciences; 06108 Nice cedex 02 France
| | - Anne Vielle
- Institut de Biologie Valrose, CNRS UMR7277; Parc Valrose; 06108 Nice cedex 02 France
- Université Nice Sophia Antipolis; UFR Sciences; 06108 Nice cedex 02 France
| | - Clotilde Gimond
- Institut de Biologie Valrose, CNRS UMR7277; Parc Valrose; 06108 Nice cedex 02 France
- Université Nice Sophia Antipolis; UFR Sciences; 06108 Nice cedex 02 France
| | - Céline Ferrari
- Institut de Biologie Valrose, CNRS UMR7277; Parc Valrose; 06108 Nice cedex 02 France
- Université Nice Sophia Antipolis; UFR Sciences; 06108 Nice cedex 02 France
| | - Christian Braendle
- Institut de Biologie Valrose, CNRS UMR7277; Parc Valrose; 06108 Nice cedex 02 France
- Université Nice Sophia Antipolis; UFR Sciences; 06108 Nice cedex 02 France
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14
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Fox PM, Vought VE, Hanazawa M, Lee MH, Maine EM, Schedl T. Cyclin E and CDK-2 regulate proliferative cell fate and cell cycle progression in the C. elegans germline. Development 2011; 138:2223-34. [PMID: 21558371 DOI: 10.1242/dev.059535] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The C. elegans germline provides an excellent model for analyzing the regulation of stem cell activity and the decision to differentiate and undergo meiotic development. The distal end of the adult hermaphrodite germline contains the proliferative zone, which includes a population of mitotically cycling cells and cells in meiotic S phase, followed by entry into meiotic prophase. The proliferative fate is specified by somatic distal tip cell (DTC) niche-germline GLP-1 Notch signaling through repression of the redundant GLD-1 and GLD-2 pathways that promote entry into meiosis. Here, we describe characteristics of the proliferative zone, including cell cycle kinetics and population dynamics, as well as the role of specific cell cycle factors in both cell cycle progression and the decision between the proliferative and meiotic cell fate. Mitotic cell cycle progression occurs rapidly, continuously, with little or no time spent in G1, and with cyclin E (CYE-1) levels and activity high throughout the cell cycle. In addition to driving mitotic cell cycle progression, CYE-1 and CDK-2 also play an important role in proliferative fate specification. Genetic analysis indicates that CYE-1/CDK-2 promotes the proliferative fate downstream or in parallel to the GLD-1 and GLD-2 pathways, and is important under conditions of reduced GLP-1 signaling, possibly corresponding to mitotically cycling proliferative zone cells that are displaced from the DTC niche. Furthermore, we find that GLP-1 signaling regulates a third pathway, in addition to the GLD-1 and GLD-2 pathways and also independent of CYE-1/CDK-2, to promote the proliferative fate/inhibit meiotic entry.
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Affiliation(s)
- Paul M Fox
- Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
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Morgan DE, Crittenden SL, Kimble J. The C. elegans adult male germline: stem cells and sexual dimorphism. Dev Biol 2010; 346:204-14. [PMID: 20659446 PMCID: PMC2945412 DOI: 10.1016/j.ydbio.2010.07.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/14/2010] [Accepted: 07/18/2010] [Indexed: 01/07/2023]
Abstract
The hermaphrodite Caenorhabditis elegans germline has become a classic model for stem cell regulation, but the male C. elegans germline has been largely neglected. This work provides a cellular analysis of the adult C. elegans male germline, focusing on its predicted stem cell region in the distal gonad. The goals of this study were two-fold: to establish the C. elegans male germline as a stem cell model and to identify sex-specific traits of potential relevance to the sperm/oocyte decision. Our results support two major conclusions. First, adult males do indeed possess a population of germline stem cells (GSCs) with properties similar to those of hermaphrodite GSCs (lack of cell cycle quiescence and lack of reproducibly oriented divisions). Second, germ cells in the mitotic region, including those most distal within the niche, exhibit sex-specific behaviors (e.g. cell cycle length) and therefore have acquired sexual identity. Previous studies demonstrated that some germ cells are not committed to a sperm or oocyte cell fate, even in adults. We propose that germ cells can acquire sexual identity without being committed to a sperm or oocyte cell fate.
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Affiliation(s)
- Dyan E. Morgan
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Sarah L. Crittenden
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Judith Kimble
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706 USA
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA
- Laboratory of Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706 USA
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI 53706 USA
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Cinquin O, Crittenden SL, Morgan DE, Kimble J. Progression from a stem cell-like state to early differentiation in the C. elegans germ line. Proc Natl Acad Sci U S A 2010; 107:2048-53. [PMID: 20080700 PMCID: PMC2836686 DOI: 10.1073/pnas.0912704107] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Controls of stem cell maintenance and early differentiation are known in several systems. However, the progression from stem cell self-renewal to overt signs of early differentiation is a poorly understood but important problem in stem cell biology. The Caenorhabditis elegans germ line provides a genetically defined model for studying that progression. In this system, a single-celled mesenchymal niche, the distal tip cell (DTC), employs GLP-1/Notch signaling and an RNA regulatory network to balance self-renewal and early differentiation within the "mitotic region," which continuously self-renews while generating new gametes. Here, we investigate germ cells in the mitotic region for their capacity to differentiate and their state of maturation. Two distinct pools emerge. The "distal pool" is maintained by the DTC in an essentially uniform and immature or "stem cell-like" state; the "proximal pool," by contrast, contains cells that are maturing toward early differentiation and are likely transit-amplifying cells. A rough estimate of pool sizes is 30-70 germ cells in the distal immature pool and approximately 150 in the proximal transit-amplifying pool. We present a simple model for how the network underlying the switch between self-renewal and early differentiation may be acting in these two pools. According to our model, the self-renewal mode of the network maintains the distal pool in an immature state, whereas the transition between self-renewal and early differentiation modes of the network underlies the graded maturation of germ cells in the proximal pool. We discuss implications of this model for controls of stem cells more broadly.
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Affiliation(s)
- Olivier Cinquin
- Howard Hughes Medical Institute,
- Department of Developmental and Cell Biology and Center for Complex Biological Systems, University of California, Irvine, CA 92697
| | | | | | - Judith Kimble
- Howard Hughes Medical Institute,
- Program in Cellular and Molecular Biology, and
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706; and
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Structural basis for specific recognition of multiple mRNA targets by a PUF regulatory protein. Proc Natl Acad Sci U S A 2009; 106:20186-91. [PMID: 19901328 DOI: 10.1073/pnas.0812076106] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Caenorhabditis elegans fem-3 binding factor (FBF) is a founding member of the PUMILIO/FBF (PUF) family of mRNA regulatory proteins. It regulates multiple mRNAs critical for stem cell maintenance and germline development. Here, we report crystal structures of FBF in complex with 6 different 9-nt RNA sequences, including elements from 4 natural mRNAs. These structures reveal that FBF binds to conserved bases at positions 1-3 and 7-8. The key specificity determinant of FBF vs. other PUF proteins lies in positions 4-6. In FBF/RNA complexes, these bases stack directly with one another and turn away from the RNA-binding surface. A short region of FBF is sufficient to impart its unique specificity and lies directly opposite the flipped bases. We suggest that this region imposes a flattened curvature on the protein; hence, the requirement for the additional nucleotide. The principles of FBF/RNA recognition suggest a general mechanism by which PUF proteins recognize distinct families of RNAs yet exploit very nearly identical atomic contacts in doing so.
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