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Blundon JM, Cesar BI, Bae JW, Čavka I, Haversat J, Ries J, Köhler S, Kim Y. Skp1 proteins are structural components of the synaptonemal complex in C. elegans. SCIENCE ADVANCES 2024; 10:eadl4876. [PMID: 38354250 PMCID: PMC10866564 DOI: 10.1126/sciadv.adl4876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/12/2024] [Indexed: 02/16/2024]
Abstract
The synaptonemal complex (SC) is a zipper-like protein assembly that links homologous chromosomes to regulate recombination and segregation during meiosis. The SC has been notoriously refractory to in vitro reconstitution, thus leaving its molecular organization largely unknown. Here, we report a moonlighting function of two paralogous S-phase kinase-associated protein 1 (Skp1)-related proteins (SKR-1 and SKR-2), well-known adaptors of the Skp1-Cul1-F-box (SCF) ubiquitin ligase, as the key missing components of the SC in Caenorhabditis elegans. SKR proteins repurpose their SCF-forming interfaces to dimerize and interact with meiosis-specific SC proteins, thereby driving synapsis independent of SCF activity. SKR-1 enables the formation of the long-sought-after soluble complex with previously identified SC proteins in vitro, which we propose it to represent a complete SC building block. Our findings demonstrate how a conserved cell cycle regulator has been co-opted to interact with rapidly evolving meiotic proteins to construct the SC and provide a foundation for understanding its structure and assembly mechanisms.
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Affiliation(s)
- Joshua M. Blundon
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Brenda I. Cesar
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jung Woo Bae
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ivana Čavka
- The European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Jocelyn Haversat
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jonas Ries
- The European Molecular Biology Laboratory, Heidelberg, Germany
| | - Simone Köhler
- The European Molecular Biology Laboratory, Heidelberg, Germany
| | - Yumi Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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2
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Kumari P, Thuestad L, Ciosk R. Post-transcriptional repression of CFP-1 expands the regulatory repertoire of LIN-41/TRIM71. Nucleic Acids Res 2023; 51:10668-10680. [PMID: 37670562 PMCID: PMC10602926 DOI: 10.1093/nar/gkad729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 09/07/2023] Open
Abstract
The Caenorhabditis elegans LIN-41/TRIM71 is a well-studied example of a versatile regulator of mRNA fate, which plays different biological functions involving distinct post-transcriptional mechanisms. In the soma, LIN-41 determines the timing of developmental transitions between larval stages. The somatic LIN-41 recognizes specific mRNAs via LREs (LIN-41 Recognition Elements) and elicits either mRNA decay or translational repression. In the germline, LIN-41 controls the oocyte-to-embryo transition (OET), although the relevant targets and regulatory mechanisms are poorly understood. The germline LIN-41 was suggested to regulate mRNAs indirectly by associating with another RNA-binding protein. We show here that LIN-41 can also regulate germline mRNAs via the LREs. Through a computational-experimental analysis, we identified the germline mRNAs potentially controlled via LREs and validated one target, the cfp-1 mRNA, encoding a conserved chromatin modifier. Our analysis suggests that cfp-1 may be a long-sought target whose LIN-41-mediated regulation during OET facilitates the transcriptional reprogramming underlying the switch from germ- to somatic cell identity.
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Affiliation(s)
- Pooja Kumari
- Department of Biosciences, University of Oslo, Oslo 0316, Norway
| | | | - Rafal Ciosk
- Department of Biosciences, University of Oslo, Oslo 0316, Norway
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3
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de la Cova CC. The Highs and Lows of FBXW7: New Insights into Substrate Affinity in Disease and Development. Cells 2023; 12:2141. [PMID: 37681873 PMCID: PMC10486803 DOI: 10.3390/cells12172141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/16/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023] Open
Abstract
FBXW7 is a critical regulator of cell cycle, cell signaling, and development. A highly conserved F-box protein and component of the SKP1-Cullin-F-box (SCF) complex, FBXW7 functions as a recognition subunit within a Cullin-RING E3 ubiquitin ligase responsible for ubiquitinating substrate proteins and targeting them for proteasome-mediated degradation. In human cells, FBXW7 promotes degradation of a large number of substrate proteins, including many that impact disease, such as NOTCH1, Cyclin E, MYC, and BRAF. A central focus for investigation has been to understand the molecular mechanisms that allow the exquisite substrate specificity exhibited by FBXW7. Recent work has produced a clearer understanding of how FBXW7 physically interacts with both high-affinity and low-affinity substrates. We review new findings that provide insights into the consequences of "hotspot" missense mutations of FBXW7 that are found in human cancers. Finally, we discuss how the FBXW7-substrate interaction, and the kinases responsible for substrate phosphorylation, contribute to patterned protein degradation in C. elegans development.
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Affiliation(s)
- Claire C de la Cova
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
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4
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Albarqi MMY, Ryder SP. The role of RNA-binding proteins in orchestrating germline development in Caenorhabditis elegans. Front Cell Dev Biol 2023; 10:1094295. [PMID: 36684428 PMCID: PMC9846511 DOI: 10.3389/fcell.2022.1094295] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/19/2022] [Indexed: 01/06/2023] Open
Abstract
RNA passed from parents to progeny controls several aspects of early development. The germline of the free-living nematode Caenorhabditis elegans contains many families of evolutionarily conserved RNA-binding proteins (RBPs) that target the untranslated regions of mRNA transcripts to regulate their translation and stability. In this review, we summarize what is known about the binding specificity of C. elegans germline RNA-binding proteins and the mechanisms of mRNA regulation that contribute to their function. We examine the emerging role of miRNAs in translational regulation of germline and embryo development. We also provide an overview of current technology that can be used to address the gaps in our understanding of RBP regulation of mRNAs. Finally, we present a hypothetical model wherein multiple 3'UTR-mediated regulatory processes contribute to pattern formation in the germline to ensure the proper and timely localization of germline proteins and thus a functional reproductive system.
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5
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Mastrandreas P, Boglari C, Arnold A, Peter F, de Quervain DJF, Papassotiropoulos A, Stetak A. Phosphorylation of MSI-1 is implicated in the regulation of associative memory in Caenorhabditis elegans. PLoS Genet 2022; 18:e1010420. [PMID: 36223338 PMCID: PMC9555661 DOI: 10.1371/journal.pgen.1010420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/09/2022] [Indexed: 11/07/2022] Open
Abstract
The Musashi family of RNA-binding proteins controls several biological processes including stem cell maintenance, cell division and neural function. Previously, we demonstrated that the C. elegans Musashi ortholog, msi-1, regulates forgetting via translational repression of the Arp2/3 actin-branching complex. However, the mechanisms controlling MSI-1 activity during the regulation of forgetting are currently unknown. Here we investigated the effects of protein phosphorylation on MSI-1 activity. We showed that MSI-1 function is likely controlled by alterations of its activity rather than its expression levels. Furthermore, we found that MSI-1 is phosphorylated and using mass spectrometry we identified MSI-1 phosphorylation at three residues (T18, S19 and S34). CRISPR-based manipulations of MSI-1 phosphorylation sites revealed that phosphorylation is necessary for MSI-1 function in both short- and long-term aversive olfactory associative memory. Thus, our study provides insight into the mechanisms regulating memory-related MSI-1 activity and may facilitate the development of novel therapeutic approaches. Understanding neural circuits and molecular mechanisms underlying learning and memory are the major challenges of neuroscience. It is a generally accepted model that a learning event causes modification of synapses; strengthening some within a circuit and weakening others (termed “synaptic plasticity”). A plastic nervous system requires not only the ability to acquire and store but also to forget new inputs. While learning and memory is widely investigated, clear-cut evidence for mechanisms involved in forgetting is still sparse. Previously, we demonstrated the role of the protein Musashi (MSI-1) in the active regulation of forgetting in the nematode C. elegans. Here we investigated the role of protein modification (phosphorylation) as a possible regulatory mechanism of the MSI-1 protein activity. We found that MSI-1 protein is modified at different positions and all of these modifications at the protein level contribute to the correct activity of the protein leading to active forgetting of short and long-term memories.
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Affiliation(s)
- Pavlina Mastrandreas
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Csaba Boglari
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Andreas Arnold
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Fabian Peter
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
| | - Dominique J.-F. de Quervain
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Cognitive Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- University Psychiatric Clinics, University of Basel, Basel, Switzerland
| | - Andreas Papassotiropoulos
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
- University Psychiatric Clinics, University of Basel, Basel, Switzerland
| | - Attila Stetak
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Division of Molecular Neuroscience, Department of Psychology, University of Basel, Basel, Switzerland
- Biozentrum, Life Sciences Training Facility, University of Basel, Basel, Switzerland
- University Psychiatric Clinics, University of Basel, Basel, Switzerland
- * E-mail:
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6
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Spike CA, Tsukamoto T, Greenstein D. Ubiquitin ligases and a processive proteasome facilitate protein clearance during the oocyte-to-embryo transition in Caenorhabditis elegans. Genetics 2022; 221:iyac051. [PMID: 35377419 PMCID: PMC9071522 DOI: 10.1093/genetics/iyac051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 03/27/2022] [Indexed: 02/07/2023] Open
Abstract
The ubiquitin-mediated degradation of oocyte translational regulatory proteins is a conserved feature of the oocyte-to-embryo transition. In the nematode Caenorhabditis elegans, multiple translational regulatory proteins, including the TRIM-NHL RNA-binding protein LIN-41/Trim71 and the Pumilio-family RNA-binding proteins PUF-3 and PUF-11, are degraded during the oocyte-to-embryo transition. Degradation of each protein requires activation of the M-phase cyclin-dependent kinase CDK-1, is largely complete by the end of the first meiotic division and does not require the anaphase-promoting complex. However, only LIN-41 degradation requires the F-box protein SEL-10/FBW7/Cdc4p, the substrate recognition subunit of an SCF-type E3 ubiquitin ligase. This finding suggests that PUF-3 and PUF-11, which localize to LIN-41-containing ribonucleoprotein particles, are independently degraded through the action of other factors and that the oocyte ribonucleoprotein particles are disassembled in a concerted fashion during the oocyte-to-embryo transition. We develop and test the hypothesis that PUF-3 and PUF-11 are targeted for degradation by the proteasome-associated HECT-type ubiquitin ligase ETC-1/UBE3C/Hul5, which is broadly expressed in C. elegans. We find that several GFP-tagged fusion proteins that are degraded during the oocyte-to-embryo transition, including fusions with PUF-3, PUF-11, LIN-41, IFY-1/Securin, and CYB-1/Cyclin B, are incompletely degraded when ETC-1 function is compromised. However, it is the fused GFP moiety that appears to be the critical determinant of this proteolysis defect. These findings are consistent with a conserved role for ETC-1 in promoting proteasome processivity and suggest that proteasomal processivity is an important element of the oocyte-to-embryo transition during which many key oocyte regulatory proteins are rapidly targeted for degradation.
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Affiliation(s)
- Caroline A Spike
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tatsuya Tsukamoto
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - David Greenstein
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
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7
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Kinterová V, Kaňka J, Bartková A, Toralová T. SCF Ligases and Their Functions in Oogenesis and Embryogenesis-Summary of the Most Important Findings throughout the Animal Kingdom. Cells 2022; 11:234. [PMID: 35053348 PMCID: PMC8774150 DOI: 10.3390/cells11020234] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 12/10/2022] Open
Abstract
SCF-dependent proteolysis was first discovered via genetic screening of budding yeast almost 25 years ago. In recent years, more and more functions of SCF (Skp1-Cullin 1-F-box) ligases have been described, and we can expect the number of studies on this topic to increase. SCF ligases, which are E3 ubiquitin multi-protein enzymes, catalyse protein ubiquitination and thus allow protein degradation mediated by the 26S proteasome. They play a crucial role in the degradation of cell cycle regulators, regulation of the DNA repair and centrosome cycle and play an important role in several diseases. SCF ligases seem to be needed during all phases of development, from oocyte formation through fertilization, activation of the embryonic genome to embryo implantation. In this review, we summarize known data on SCF ligase-mediated degradation during oogenesis and embryogenesis. In particular, SCFβTrCP and SCFSEL-10/FBXW7 are among the most important and best researched ligases during early development. SCFβTrCP is crucial for the oogenesis of Xenopus and mouse and also in Xenopus and Drosophila embryogenesis. SCFSEL-10/FBXW7 participates in the degradation of several RNA-binding proteins and thereby affects the regulation of gene expression during the meiosis of C. elegans. Nevertheless, a large number of SCF ligases that are primarily involved in embryogenesis remain to be elucidated.
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Affiliation(s)
- Veronika Kinterová
- Laboratory of Developmental Biology, Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, 27721 Libechov, Czech Republic; (J.K.); (A.B.); (T.T.)
| | - Jiří Kaňka
- Laboratory of Developmental Biology, Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, 27721 Libechov, Czech Republic; (J.K.); (A.B.); (T.T.)
| | - Alexandra Bartková
- Laboratory of Developmental Biology, Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, 27721 Libechov, Czech Republic; (J.K.); (A.B.); (T.T.)
- Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, 949 01 Nitra, Slovakia
| | - Tereza Toralová
- Laboratory of Developmental Biology, Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, 27721 Libechov, Czech Republic; (J.K.); (A.B.); (T.T.)
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8
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Cao WX, Karaiskakis A, Lin S, Angers S, Lipshitz HD. The F-box protein Bard (CG14317) targets the Smaug RNA-binding protein for destruction during the Drosophila maternal-to-zygotic transition. Genetics 2022; 220:iyab177. [PMID: 34757425 PMCID: PMC8733446 DOI: 10.1093/genetics/iyab177] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/11/2021] [Indexed: 01/12/2023] Open
Abstract
During the maternal-to-zygotic transition (MZT), which encompasses the earliest stages of animal embryogenesis, a subset of maternally supplied gene products is cleared, thus permitting activation of zygotic gene expression. In the Drosophila melanogaster embryo, the RNA-binding protein Smaug (SMG) plays an essential role in progression through the MZT by translationally repressing and destabilizing a large number of maternal mRNAs. The SMG protein itself is rapidly cleared at the end of the MZT by a Skp/Cullin/F-box (SCF) E3-ligase complex. Clearance of SMG requires zygotic transcription and is required for an orderly MZT. Here, we show that an F-box protein, which we name Bard (encoded by CG14317), is required for degradation of SMG. Bard is expressed zygotically and physically interacts with SMG at the end of the MZT, coincident with binding of the maternal SCF proteins, SkpA and Cullin1, and with degradation of SMG. shRNA-mediated knock-down of Bard or deletion of the bard gene in the early embryo results in stabilization of SMG protein, a phenotype that is rescued by transgenes expressing Bard. Bard thus times the clearance of SMG at the end of the MZT.
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Affiliation(s)
- Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Angelo Karaiskakis
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Sichun Lin
- Department of Pharmaceutical Sciences & Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences & Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
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9
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Samaddar M, Goudeau J, Sanchez M, Hall DH, Bohnert KA, Ingaramo M, Kenyon C. A genetic screen identifies new steps in oocyte maturation that enhance proteostasis in the immortal germ lineage. eLife 2021; 10:e62653. [PMID: 33848238 PMCID: PMC8043744 DOI: 10.7554/elife.62653] [Citation(s) in RCA: 6] [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: 09/02/2020] [Accepted: 03/24/2021] [Indexed: 12/24/2022] Open
Abstract
Somatic cells age and die, but the germ-cell lineage is immortal. In Caenorhabditis elegans, germline immortality involves proteostasis renewal at the beginning of each new generation, when oocyte maturation signals from sperm trigger the clearance of carbonylated proteins and protein aggregates. Here, we explore the cell biology of this proteostasis renewal in the context of a whole-genome RNAi screen. Oocyte maturation signals are known to trigger protein-aggregate removal via lysosome acidification. Our findings suggest that lysosomes are acidified as a consequence of changes in endoplasmic reticulum activity that permit assembly of the lysosomal V-ATPase, which in turn allows lysosomes to clear the aggregates via microautophagy. We define two functions for mitochondria, both of which appear to be independent of ATP generation. Many genes from the screen also regulate lysosome acidification and age-dependent protein aggregation in the soma, suggesting a fundamental mechanistic link between proteostasis renewal in the germline and somatic longevity.
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Affiliation(s)
| | - Jérôme Goudeau
- Calico Life Sciences LLCSouth San FranciscoUnited States
| | - Melissa Sanchez
- Department of Molecular and Cellular Biology, University of California, BerkeleyBerkeleyUnited States
| | - David H Hall
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineNew YorkUnited States
| | - K Adam Bohnert
- Calico Life Sciences LLCSouth San FranciscoUnited States
| | - Maria Ingaramo
- Calico Life Sciences LLCSouth San FranciscoUnited States
| | - Cynthia Kenyon
- Calico Life Sciences LLCSouth San FranciscoUnited States
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10
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Goudeau J, Samaddar M, Bohnert KA, Kenyon C. Addendum: A lysosomal switch triggers proteostasis renewal in the immortal C. elegans germ lineage. Nature 2020; 580:E5. [PMID: 32269336 DOI: 10.1038/s41586-020-2108-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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11
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Hubbard EJA, Schedl T. Biology of the Caenorhabditis elegans Germline Stem Cell System. Genetics 2019; 213:1145-1188. [PMID: 31796552 PMCID: PMC6893382 DOI: 10.1534/genetics.119.300238] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 09/09/2019] [Indexed: 12/14/2022] Open
Abstract
Stem cell systems regulate tissue development and maintenance. The germline stem cell system is essential for animal reproduction, controlling both the timing and number of progeny through its influence on gamete production. In this review, we first draw general comparisons to stem cell systems in other organisms, and then present our current understanding of the germline stem cell system in Caenorhabditis elegans In contrast to stereotypic somatic development and cell number stasis of adult somatic cells in C. elegans, the germline stem cell system has a variable division pattern, and the system differs between larval development, early adult peak reproduction and age-related decline. We discuss the cell and developmental biology of the stem cell system and the Notch regulated genetic network that controls the key decision between the stem cell fate and meiotic development, as it occurs under optimal laboratory conditions in adult and larval stages. We then discuss alterations of the stem cell system in response to environmental perturbations and aging. A recurring distinction is between processes that control stem cell fate and those that control cell cycle regulation. C. elegans is a powerful model for understanding germline stem cells and stem cell biology.
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Affiliation(s)
- E Jane Albert Hubbard
- Skirball Institute of Biomolecular Medicine, Departments of Cell Biology and Pathology, New York University School of Medicine, New York 10016
| | - Tim Schedl
- and Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
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12
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Vastenhouw NL, Cao WX, Lipshitz HD. The maternal-to-zygotic transition revisited. Development 2019; 146:146/11/dev161471. [PMID: 31189646 DOI: 10.1242/dev.161471] [Citation(s) in RCA: 207] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The development of animal embryos is initially directed by maternal gene products. Then, during the maternal-to-zygotic transition (MZT), developmental control is handed to the zygotic genome. Extensive research in both vertebrate and invertebrate model organisms has revealed that the MZT can be subdivided into two phases, during which very different modes of gene regulation are implemented: initially, regulation is exclusively post-transcriptional and post-translational, following which gradual activation of the zygotic genome leads to predominance of transcriptional regulation. These changes in the gene expression program of embryos are precisely controlled and highly interconnected. Here, we review current understanding of the mechanisms that underlie handover of developmental control during the MZT.
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Affiliation(s)
- Nadine L Vastenhouw
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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13
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Kocsisova Z, Kornfeld K, Schedl T. Rapid population-wide declines in stem cell number and activity during reproductive aging in C. elegans. Development 2019; 146:dev173195. [PMID: 30936182 PMCID: PMC6503983 DOI: 10.1242/dev.173195] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/13/2019] [Indexed: 01/03/2023]
Abstract
C. elegans hermaphrodites display dramatic age-related decline of reproduction early in life, while somatic functions are still robust. To understand reproductive aging, we analyzed the assembly line of oocyte production that generates fertilized eggs. Aging germlines displayed both sporadic and population-wide changes. A small fraction of aging animals displayed endomitotic oocytes in the germline and other defects. By contrast, all animals displayed age-related decreases in germline size and function. As early as day 3 of adulthood, animals displayed fewer stem cells and a slower cell cycle, which combine to substantially decrease progenitor zone output. The C. elegans germline is the only adult tissue that contains stem cells, allowing the analysis of stem cells in aging. To investigate the mechanism of the decrease in stem cell number, we analyzed the Notch signaling pathway. The Notch effectors LST-1 and SYGL-1 displayed age-related decreases in expression domains, suggesting a role for Notch signaling in germline aging. The results indicate that although sporadic defects account for the sterility of some animals, population-wide changes account for the overall pattern of reproductive aging.
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Affiliation(s)
- Zuzana Kocsisova
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
- Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Tim Schedl
- Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
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