1
|
Thor S. Indirect neurogenesis in space and time. Nat Rev Neurosci 2024; 25:519-534. [PMID: 38951687 DOI: 10.1038/s41583-024-00833-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2024] [Indexed: 07/03/2024]
Abstract
During central nervous system (CNS) development, neural progenitor cells (NPCs) generate neurons and glia in two different ways. In direct neurogenesis, daughter cells differentiate directly into neurons or glia, whereas in indirect neurogenesis, neurons or glia are generated after one or more daughter cell divisions. Intriguingly, indirect neurogenesis is not stochastically deployed and plays instructive roles during CNS development: increased generation of cells from specific lineages; increased generation of early or late-born cell types within a lineage; and increased cell diversification. Increased indirect neurogenesis might contribute to the anterior CNS expansion evident throughout the Bilateria and help to modify brain-region size without requiring increased NPC numbers or extended neurogenesis. Increased indirect neurogenesis could be an evolutionary driver of the gyrencephalic (that is, folded) cortex that emerged during mammalian evolution and might even have increased during hominid evolution. Thus, selection of indirect versus direct neurogenesis provides a powerful developmental and evolutionary instrument that drives not only the evolution of CNS complexity but also brain expansion and modulation of brain-region size, and thereby the evolution of increasingly advanced cognitive abilities. This Review describes indirect neurogenesis in several model species and humans, and highlights some of the molecular genetic mechanisms that control this important process.
Collapse
Affiliation(s)
- Stefan Thor
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia.
| |
Collapse
|
2
|
Stewart RK, Nguyen P, Laederach A, Volkan PC, Sawyer JK, Fox DT. Orb2 enables rare-codon-enriched mRNA expression during Drosophila neuron differentiation. Nat Commun 2024; 15:5270. [PMID: 38902233 PMCID: PMC11190236 DOI: 10.1038/s41467-024-48344-8] [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: 08/10/2023] [Accepted: 04/25/2024] [Indexed: 06/22/2024] Open
Abstract
Regulation of codon optimality is an increasingly appreciated layer of cell- and tissue-specific protein expression control. Here, we use codon-modified reporters to show that differentiation of Drosophila neural stem cells into neurons enables protein expression from rare-codon-enriched genes. From a candidate screen, we identify the cytoplasmic polyadenylation element binding (CPEB) protein Orb2 as a positive regulator of rare-codon-dependent mRNA stability in neurons. Using RNA sequencing, we reveal that Orb2-upregulated mRNAs in the brain with abundant Orb2 binding sites have a rare-codon bias. From these Orb2-regulated mRNAs, we demonstrate that rare-codon enrichment is important for mRNA stability and social behavior function of the metabotropic glutamate receptor (mGluR). Our findings reveal a molecular mechanism by which neural stem cell differentiation shifts genetic code regulation to enable critical mRNA stability and protein expression.
Collapse
Affiliation(s)
- Rebeccah K Stewart
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC, USA
- Duke Regeneration Center, Duke University, Durham, NC, USA
| | - Patrick Nguyen
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC, USA
| | - Alain Laederach
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | | | - Jessica K Sawyer
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC, USA
- Duke Regeneration Center, Duke University, Durham, NC, USA
| | - Donald T Fox
- Department of Pharmacology & Cancer Biology, Duke University, Durham, NC, USA.
- Duke Regeneration Center, Duke University, Durham, NC, USA.
| |
Collapse
|
3
|
Komori H, Rastogi G, Bugay JP, Luo H, Lin S, Angers S, Smibert CA, Lipshitz HD, Lee CY. Post-transcriptional regulatory pre-complex assembly drives timely cell-state transitions during differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.29.591706. [PMID: 38746105 PMCID: PMC11092521 DOI: 10.1101/2024.04.29.591706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Complexes that control mRNA stability and translation promote timely cell-state transitions during differentiation by ensuring appropriate expression patterns of key developmental regulators. The Drosophila RNA-binding protein Brain tumor (Brat) promotes degradation of target transcripts during the maternal-to-zygotic transition in syncytial embryos and in uncommitted intermediate neural progenitors (immature INPs). We identified Ubiquitin-specific protease 5 (Usp5) as a Brat interactor essential for the degradation of Brat target mRNAs in both cell types. Usp5 promotes Brat-dedadenylase pre-complex assembly in mitotic neural stem cells (neuroblasts) by bridging Brat and the scaffolding components of deadenylase complexes lacking their catalytic subunits. The adaptor protein Miranda binds the RNA-binding domain of Brat, limiting its ability to bind target mRNAs in mitotic neuroblasts. Cortical displacement of Miranda activates Brat-mediated mRNA decay in immature INPs. We propose that the assembly of an enzymatically inactive and RNA-binding-deficient pre-complex poises mRNA degradation machineries for rapid activation driving timely developmental transitions.
Collapse
|
4
|
Diaz LR, Gil-Ranedo J, Jaworek KJ, Nsek N, Marques JP, Costa E, Hilton DA, Bieluczyk H, Warrington O, Hanemann CO, Futschik ME, Bossing T, Barros CS. Ribogenesis boosts controlled by HEATR1-MYC interplay promote transition into brain tumour growth. EMBO Rep 2024; 25:168-197. [PMID: 38225354 PMCID: PMC10897169 DOI: 10.1038/s44319-023-00017-1] [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: 02/06/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 01/17/2024] Open
Abstract
Cell commitment to tumourigenesis and the onset of uncontrolled growth are critical determinants in cancer development but the early events directing tumour initiating cell (TIC) fate remain unclear. We reveal a single-cell transcriptome profile of brain TICs transitioning into tumour growth using the brain tumour (brat) neural stem cell-based Drosophila model. Prominent changes in metabolic and proteostasis-associated processes including ribogenesis are identified. Increased ribogenesis is a known cell adaptation in established tumours. Here we propose that brain TICs boost ribogenesis prior to tumour growth. In brat-deficient TICs, we show that this dramatic change is mediated by upregulated HEAT-Repeat Containing 1 (HEATR1) to promote ribosomal RNA generation, TIC enlargement and onset of overgrowth. High HEATR1 expression correlates with poor glioma patient survival and patient-derived glioblastoma stem cells rely on HEATR1 for enhanced ribogenesis and tumourigenic potential. Finally, we show that HEATR1 binds the master growth regulator MYC, promotes its nucleolar localisation and appears required for MYC-driven ribogenesis, suggesting a mechanism co-opted in ribogenesis reprogramming during early brain TIC development.
Collapse
Affiliation(s)
- Laura R Diaz
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Jon Gil-Ranedo
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Karolina J Jaworek
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
- School of Biological Sciences, Bangor University, LL57 2UW, Bangor, UK
| | - Nsikan Nsek
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Joao Pinheiro Marques
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Eleni Costa
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - David A Hilton
- Department of Cellular and Anatomical Pathology, University Hospitals Plymouth, PL6 8DH, Plymouth, UK
| | - Hubert Bieluczyk
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Oliver Warrington
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, WC1N 3AR, London, UK
| | - C Oliver Hanemann
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Matthias E Futschik
- School of Biomedical Sciences, Faculty of Health, Derriford Research Facility, University of Plymouth, PL6 8BU, Plymouth, UK
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-504, Coimbra, Portugal
| | - Torsten Bossing
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Claudia S Barros
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK.
| |
Collapse
|
5
|
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.
Collapse
Affiliation(s)
- Pooja Kumari
- Department of Biosciences, University of Oslo, Oslo 0316, Norway
| | | | - Rafal Ciosk
- Department of Biosciences, University of Oslo, Oslo 0316, Norway
| |
Collapse
|
6
|
Harrison MM, Marsh AJ, Rushlow CA. Setting the stage for development: the maternal-to-zygotic transition in Drosophila. Genetics 2023; 225:iyad142. [PMID: 37616526 PMCID: PMC10550319 DOI: 10.1093/genetics/iyad142] [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: 05/18/2023] [Accepted: 07/18/2023] [Indexed: 08/26/2023] Open
Abstract
The zygote has a daunting task ahead of itself; it must develop from a single cell (fertilized egg) into a fully functioning adult with a multitude of different cell types. In the beginning, the zygote has help from its mother, in the form of gene products deposited into the egg, but eventually, it must rely on its own resources to proceed through development. The transfer of developmental control from the mother to the embryo is called the maternal-to-zygotic transition (MZT). All animals undergo this transition, which is defined by two main processes-the degradation of maternal RNAs and the synthesis of new RNAs from the zygote's own genome. Here, we review the regulation of the MZT in Drosophila, but given the broad conservation of this essential process, much of the regulation is shared among metazoans.
Collapse
Affiliation(s)
- Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706USA
| | - Audrey J Marsh
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706USA
| | | |
Collapse
|
7
|
Gao S, Xue S, Gao T, Lu R, Zhang X, Zhang Y, Zhang K, Li R. Transcriptome analysis reveals the role of Zelda in the regulation of embryonic and wing development of Tribolium castaneum. BULLETIN OF ENTOMOLOGICAL RESEARCH 2023; 113:587-597. [PMID: 37476851 DOI: 10.1017/s0007485323000263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Zinc finger protein (Zelda) of Tribolium castaneum (TcZelda) has been showed to play pivotal roles in embryonic development and metamorphosis. However, the regulatory mechanism of TcZelda associated with these physiology processes is unclear. Herein, the developmental expression profile showed that Zelda of T. castaneum was highly expressed in early eggs. Tissue expression profiling revealed that TcZelda was mainly expressed in the larval head and adult ovary of late adults and late larvae. TcZelda knockdown led to a 95% mortality rate in adults. These results suggested that TcZelda is related to the activation of the zygote genome in early embryonic development. Furthermore, 592 differentially expressed genes were identified from the dsZelda treated group. Compared with the control group, altered disjunction (ALD) and AGAP005368-PA (GAP) in the dsZelda group were significantly down-regulated, while TGF-beta, propeptide (TGF) was significantly up-regulated, suggesting that TcZelda may be involved in insect embryonic development. In addition, the expression of Ubx ultrabithorax (UBX), Cx cephalothorax (CX), En engrailed (EN), and two Endocuticle structural glycoprotein sgabd (ABD) genes were significantly down-regulated, suggesting that they may cooperate with TcZelda to regulate the development of insect wings. Additionally, Elongation (ELO), fatty acid synthase (FAS), and fatty acyl-CoA desaturase (FAD) expression was inhibited in dsZelda insects, which could disturb the lipase signaling pathways, thus, disrupting the insect reproductive system and pheromone synthesis. These results may help reveal the function of TcZelda in insects and the role of certain genes in the gene regulatory network and provide new ideas for the prevention and control of T. castaneum.
Collapse
Affiliation(s)
- Shanshan Gao
- Department of Food and Bioengineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Shuang Xue
- Department of Food and Bioengineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Tian Gao
- Department of Food and Bioengineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Ruixue Lu
- Department of Food and Bioengineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Xinyi Zhang
- Department of Food and Bioengineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Yonglei Zhang
- College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China
| | - Kunpeng Zhang
- Department of Food and Bioengineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Ruimin Li
- Department of Food and Bioengineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| |
Collapse
|
8
|
Stewart RK, Nguyen P, Laederach A, Volkan PC, Sawyer JK, Fox DT. Orb2 enables rare-codon-enriched mRNA expression during Drosophila neuron differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.26.550700. [PMID: 37546801 PMCID: PMC10402044 DOI: 10.1101/2023.07.26.550700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Regulation of codon optimality is an increasingly appreciated layer of cell- and tissue-specific protein expression control. Here, we use codon-modified reporters to show that differentiation of Drosophila neural stem cells into neurons enables protein expression from rare-codon-enriched genes. From a candidate screen, we identify the cytoplasmic polyadenylation element binding (CPEB) protein Orb2 as a positive regulator of rare-codon-dependent expression in neurons. Using RNA sequencing, we reveal that Orb2-upregulated mRNAs in the brain with abundant Orb2 binding sites have a rare-codon bias. From these Orb2-regulated mRNAs, we demonstrate that rare-codon enrichment is important for expression control and social behavior function of the metabotropic glutamate receptor (mGluR). Our findings reveal a molecular mechanism by which neural stem cell differentiation shifts genetic code regulation to enable critical mRNA and protein expression.
Collapse
|
9
|
Rajan A, Anhezini L, Rives-Quinto N, Chhabra JY, Neville MC, Larson ED, Goodwin SF, Harrison MM, Lee CY. Low-level repressive histone marks fine-tune gene transcription in neural stem cells. eLife 2023; 12:e86127. [PMID: 37314324 PMCID: PMC10344426 DOI: 10.7554/elife.86127] [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: 01/11/2023] [Accepted: 06/11/2023] [Indexed: 06/15/2023] Open
Abstract
Coordinated regulation of gene activity by transcriptional and translational mechanisms poise stem cells for a timely cell-state transition during differentiation. Although important for all stemness-to-differentiation transitions, mechanistic understanding of the fine-tuning of gene transcription is lacking due to the compensatory effect of translational control. We used intermediate neural progenitor (INP) identity commitment to define the mechanisms that fine-tune stemness gene transcription in fly neural stem cells (neuroblasts). We demonstrate that the transcription factor FruitlessC (FruC) binds cis-regulatory elements of most genes uniquely transcribed in neuroblasts. Loss of fruC function alone has no effect on INP commitment but drives INP dedifferentiation when translational control is reduced. FruC negatively regulates gene expression by promoting low-level enrichment of the repressive histone mark H3K27me3 in gene cis-regulatory regions. Identical to fruC loss-of-function, reducing Polycomb Repressive Complex 2 activity increases stemness gene activity. We propose low-level H3K27me3 enrichment fine-tunes gene transcription in stem cells, a mechanism likely conserved from flies to humans.
Collapse
Affiliation(s)
- Arjun Rajan
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Lucas Anhezini
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Noemi Rives-Quinto
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Jay Y Chhabra
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Elizabeth D Larson
- Department of Biomolecular Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
- Department of Cell and Developmental Biology, University of Michigan Medical SchoolAnn ArborUnited States
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan Medical SchoolAnn ArborUnited States
- Rogel Cancer Center, University of Michigan Medical SchoolAnn ArborUnited States
| |
Collapse
|
10
|
Niu N, Ye J, Hu Z, Zhang J, Wang Y. Regulative Roles of Metabolic Plasticity Caused by Mitochondrial Oxidative Phosphorylation and Glycolysis on the Initiation and Progression of Tumorigenesis. Int J Mol Sci 2023; 24:ijms24087076. [PMID: 37108242 PMCID: PMC10139088 DOI: 10.3390/ijms24087076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/23/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
One important feature of tumour development is the regulatory role of metabolic plasticity in maintaining the balance of mitochondrial oxidative phosphorylation and glycolysis in cancer cells. In recent years, the transition and/or function of metabolic phenotypes between mitochondrial oxidative phosphorylation and glycolysis in tumour cells have been extensively studied. In this review, we aimed to elucidate the characteristics of metabolic plasticity (emphasizing their effects, such as immune escape, angiogenesis migration, invasiveness, heterogeneity, adhesion, and phenotypic properties of cancers, among others) on tumour progression, including the initiation and progression phases. Thus, this article provides an overall understanding of the influence of abnormal metabolic remodeling on malignant proliferation and pathophysiological changes in carcinoma.
Collapse
Affiliation(s)
- Nan Niu
- Shenzhen Engineering Labortaory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Lihu Campus of Shenzhen University, Shenzhen 518055, China
- College of Physics and Optoelectronic Engineering, Canghai Campus of Shenzhen University, Shenzhen 518060, China
| | - Jinfeng Ye
- Shenzhen Engineering Labortaory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Lihu Campus of Shenzhen University, Shenzhen 518055, China
| | - Zhangli Hu
- Shenzhen Engineering Labortaory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Lihu Campus of Shenzhen University, Shenzhen 518055, China
| | - Junbin Zhang
- Shenzhen Engineering Labortaory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Lihu Campus of Shenzhen University, Shenzhen 518055, China
| | - Yun Wang
- Shenzhen Engineering Labortaory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Lihu Campus of Shenzhen University, Shenzhen 518055, China
| |
Collapse
|
11
|
Rebelo AR, Homem CCF. dMyc-dependent upregulation of CD98 amino acid transporters is required for Drosophila brain tumor growth. Cell Mol Life Sci 2023; 80:30. [PMID: 36609617 PMCID: PMC9823048 DOI: 10.1007/s00018-022-04668-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/30/2022] [Accepted: 12/11/2022] [Indexed: 01/07/2023]
Abstract
Tumor cells have an increased demand for nutrients to sustain their growth, but how these increased metabolic needs are ensured or how this influences tumor formation and progression remains unclear. To unravel tumor metabolic dependencies, particularly from extracellular metabolites, we have analyzed the role of plasma membrane metabolic transporters in Drosophila brain tumors. Using a well-established neural stem cell-derived tumor model, caused by brat knockdown, we have found that 13 plasma membrane metabolic transporters, including amino acid, carbohydrate and monocarboxylate transporters, are upregulated in tumors and are required for tumor growth. We identified CD98hc and several of the light chains with which it can form heterodimeric amino acid transporters, as crucial players in brat RNAi (brat IR) tumor progression. Knockdown of these components of CD98 heterodimers caused a dramatic reduction in tumor growth. Our data also reveal that the oncogene dMyc is required and sufficient for the upregulation of CD98 transporter subunits in these tumors. Furthermore, tumor-upregulated dmyc and CD98 transporters orchestrate the overactivation of the growth-promoting signaling pathway TOR, forming a core growth regulatory network to support brat IR tumor progression. Our findings highlight the important link between oncogenes, metabolism, and signaling pathways in the regulation of tumor growth and allow for a better understanding of the mechanisms necessary for tumor progression.
Collapse
Affiliation(s)
- Ana R Rebelo
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Catarina C F Homem
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade Nova de Lisboa, Lisbon, Portugal.
| |
Collapse
|
12
|
Egger B. Neural Stem Cells and Brain Tumour Models in Drosophila. Neurogenetics 2023. [DOI: 10.1007/978-3-031-07793-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
13
|
Sang R, Wu C, Xie S, Xu X, Lou Y, Ge W, Xi Y, Yang X. Mxc, a Drosophila homolog of mental retardation-associated gene NPAT, maintains neural stem cell fate. Cell Biosci 2022; 12:78. [PMID: 35642004 PMCID: PMC9153134 DOI: 10.1186/s13578-022-00820-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/22/2022] [Indexed: 01/18/2023] Open
Abstract
Background Mental retardation is a complex neurodevelopmental disorder. NPAT, a component of the histone locus body (HLB), has been implicated as a candidate gene for mental retardation, with a mechanism yet to be elucidated. Results We identified that mxc, the Drosophila ortholog of NPAT, is required for the development of nervous system. Knockdown of mxc resulted in a massive loss of neurons and locomotion dysfunction in adult flies. In the mxc mutant or RNAi knockdown larval brains, the neuroblast (NB, also known as neural stem cell) cell fate is prematurely terminated and its proliferation potential is impeded concurrent with the blocking of the differentiation process of ganglion mother cells (GMCs). A reduction of transcription levels of histone genes was shown in mxc knockdown larval brains, accompanied by DNA double-strand breaks (DSBs). The subsidence of histone transcription levels leads to prematurely termination of NB cell fate and blockage of the GMC differentiation process. Our data also show that the increase in autophagy induced by mxc knockdown in NBs could be a defense mechanism in response to abnormal HLB assembly and premature termination of NB cell fate. Conclusions Our study demonstrate that Mxc plays a critical role in maintaining neural stem cell fate and GMC differentiation in the Drosophila larval brain. This discovery may shed light on the understanding of the pathogenesis of NPAT-related mental retardation in humans. Supplementary information The online version contains supplementary material available at 10.1186/s13578-022-00820-8.
Collapse
|
14
|
Larson ED, Komori H, Fitzpatrick ZA, Krabbenhoft SD, Lee CY, Harrison M. Premature translation of the Drosophila zygotic genome activator Zelda is not sufficient to precociously activate gene expression. G3 (BETHESDA, MD.) 2022; 12:6649735. [PMID: 35876878 PMCID: PMC9434156 DOI: 10.1093/g3journal/jkac159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/15/2022] [Indexed: 05/22/2023]
Abstract
Following fertilization, the unified germ cells rapidly transition to a totipotent embryo. Maternally deposited mRNAs encode the proteins necessary for this reprogramming as the zygotic genome remains transcriptionally quiescent during the initial stages of development. The transcription factors required to activate the zygotic genome are among these maternally deposited mRNAs and are robustly translated following fertilization. In Drosophila, the mRNA encoding Zelda, the major activator of the zygotic genome, is not translated until 1 h after fertilization. Here we demonstrate that zelda translation is repressed in the early embryo by the TRIM-NHL protein Brain tumor (BRAT). BRAT also regulates Zelda levels in the larval neuroblast lineage. In the embryo, BRAT-mediated translational repression is regulated by the Pan Gu kinase, which is triggered by egg activation. The Pan Gu kinase phosphorylates translational regulators, suggesting that Pan Gu kinase activity alleviates translational repression of zelda by BRAT and coupling translation of zelda with that of other regulators of early embryonic development. Using the premature translation of zelda in embryos lacking BRAT activity, we showed that early translation of a zygotic genome activator is not sufficient to drive precocious gene expression. Instead, Zelda-target genes showed increased expression at the time they are normally activated. We propose that transition through early development requires the integration of multiple processes, including the slowing of the nuclear division cycle and activation of the zygotic genome. These processes are coordinately controlled by Pan Gu kinase-mediated regulation of translation.
Collapse
Affiliation(s)
- Elizabeth D Larson
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hideyuki Komori
- Department of Cell and Developmental Biology and Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zoe A Fitzpatrick
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Samuel D Krabbenhoft
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Cheng-Yu Lee
- Department of Cell and Developmental Biology and Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Melissa Harrison
- Corresponding author: Department of Biomolecular Chemistry, University of Wisconsin-Madison, 440 Henry Mall, 6204B Biochemical Sciences Building, Madison, WI 53706, USA.
| |
Collapse
|
15
|
Chen R, Deng X, Zhu S. The Ets protein Pointed P1 represses Asense expression in type II neuroblasts by activating Tailless. PLoS Genet 2022; 18:e1009928. [PMID: 35100262 PMCID: PMC8830786 DOI: 10.1371/journal.pgen.1009928] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/10/2022] [Accepted: 01/20/2022] [Indexed: 12/03/2022] Open
Abstract
Intermediate neural progenitors (INPs) boost the number and diversity of neurons generated from neural stem cells (NSCs) by undergoing transient proliferation. In the developing Drosophila brains, INPs are generated from type II neuroblasts (NBs). In order to maintain type II NB identity and their capability to produce INPs, the proneural protein Asense (Ase) needs to be silenced by the Ets transcription factor pointed P1 (PntP1), a master regulator of type II NB development. However, the molecular mechanisms underlying the PntP1-mediated suppression of Ase is still unclear. In this study, we utilized genetic and molecular approaches to determine the transcriptional property of PntP1 and identify the direct downstream effector of PntP1 and the cis-DNA elements that mediate the suppression of ase. Our results demonstrate that PntP1 directly activates the expression of the transcriptional repressor, Tailless (Tll), by binding to seven Ets-binding sites, and Tll in turn suppresses the expression of Ase in type II NBs by binding to two hexameric core half-site motifs. We further show that Tll provides positive feedback to maintain the expression of PntP1 and the identity of type II NBs. Thus, our study identifies a novel direct target of PntP1 and reveals mechanistic details of the specification and maintenance of the type II NB identity by PntP1. Type II neuroblasts (NBs) are the neural stem cells (NSCs) in Drosophila central brains that produce neurons by generating intermediate neural progenitors (INPs) to boost brain complexity, as mammalian NSCs do during the development of neocortex. The key to the generation of INPs from type II NBs is the suppression of proneural protein Asense (Ase) in type II NBs by the Ets family transcription factor Pointed P1 (PntP1), but how PntP1 suppresses Ase expression remains unclear. In this study, we provided evidence to demonstrate that PntP1 directly activates the orphan nuclear receptor Tailless (Tll), which in turn suppresses Ase expression to maintain the capability of type II NBs to produce INPs. Meanwhile, Tll provides positive feedback to maintain the expression of PntP1 and type II NB identity. We further identified seven PntP1 binding sites in the tll enhancer regions and two Tll binding sites in the ase regulatory regions that mediate the activation of tll and the suppression of ase, respectively. Our work reveals detailed mechanisms of the specification and maintenance of the type II NB identity by PntP1.
Collapse
Affiliation(s)
- Rui Chen
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Xiaobing Deng
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Sijun Zhu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
- * E-mail:
| |
Collapse
|
16
|
Larson ED, Komori H, Gibson TJ, Ostgaard CM, Hamm DC, Schnell JM, Lee CY, Harrison MM. Cell-type-specific chromatin occupancy by the pioneer factor Zelda drives key developmental transitions in Drosophila. Nat Commun 2021; 12:7153. [PMID: 34887421 PMCID: PMC8660810 DOI: 10.1038/s41467-021-27506-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 11/24/2021] [Indexed: 12/14/2022] Open
Abstract
During Drosophila embryogenesis, the essential pioneer factor Zelda defines hundreds of cis-regulatory regions and in doing so reprograms the zygotic transcriptome. While Zelda is essential later in development, it is unclear how the ability of Zelda to define cis-regulatory regions is shaped by cell-type-specific chromatin architecture. Asymmetric division of neural stem cells (neuroblasts) in the fly brain provide an excellent paradigm for investigating the cell-type-specific functions of this pioneer factor. We show that Zelda synergistically functions with Notch to maintain neuroblasts in an undifferentiated state. Zelda misexpression reprograms progenitor cells to neuroblasts, but this capacity is limited by transcriptional repressors critical for progenitor commitment. Zelda genomic occupancy in neuroblasts is reorganized as compared to the embryo, and this reorganization is correlated with differences in chromatin accessibility and cofactor availability. We propose that Zelda regulates essential transitions in the neuroblasts and embryo through a shared gene-regulatory network driven by cell-type-specific enhancers.
Collapse
Affiliation(s)
- Elizabeth D Larson
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Hideyuki Komori
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Tyler J Gibson
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Cyrina M Ostgaard
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Danielle C Hamm
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Jack M Schnell
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Stem Cell and Regenerative Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Cheng-Yu Lee
- Division of Genetic Medicine, Department of Internal Medicine and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
| |
Collapse
|
17
|
Rajan A, Ostgaard CM, Lee CY. Regulation of Neural Stem Cell Competency and Commitment during Indirect Neurogenesis. Int J Mol Sci 2021; 22:12871. [PMID: 34884676 PMCID: PMC8657492 DOI: 10.3390/ijms222312871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/24/2021] [Accepted: 11/24/2021] [Indexed: 11/29/2022] Open
Abstract
Indirect neurogenesis, during which neural stem cells generate neurons through intermediate progenitors, drives the evolution of lissencephalic brains to gyrencephalic brains. The mechanisms that specify intermediate progenitor identity and that regulate stem cell competency to generate intermediate progenitors remain poorly understood despite their roles in indirect neurogenesis. Well-characterized lineage hierarchy and available powerful genetic tools for manipulating gene functions make fruit fly neural stem cell (neuroblast) lineages an excellent in vivo paradigm for investigating the mechanisms that regulate neurogenesis. Type II neuroblasts in fly larval brains repeatedly undergo asymmetric divisions to generate intermediate neural progenitors (INPs) that undergo limited proliferation to increase the number of neurons generated per stem cell division. Here, we review key regulatory genes and the mechanisms by which they promote the specification and generation of INPs, safeguarding the indirect generation of neurons during fly larval brain neurogenesis. Homologs of these regulators of INPs have been shown to play important roles in regulating brain development in vertebrates. Insight into the precise regulation of intermediate progenitors will likely improve our understanding of the control of indirect neurogenesis during brain development and brain evolution.
Collapse
Affiliation(s)
- Arjun Rajan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
| | - Cyrina M. Ostgaard
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (A.R.); (C.M.O.)
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Division of Genetic Medicine, Department of Internal Medicine and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| |
Collapse
|
18
|
Brenneis G, Schwentner M, Giribet G, Beltz BS. Insights into the genetic regulatory network underlying neurogenesis in the parthenogenetic marbled crayfish Procambarus virginalis. Dev Neurobiol 2021; 81:939-974. [PMID: 34554654 DOI: 10.1002/dneu.22852] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/26/2021] [Accepted: 09/20/2021] [Indexed: 11/09/2022]
Abstract
Nervous system development has been intensely studied in insects (especially Drosophila melanogaster), providing detailed insights into the genetic regulatory network governing the formation and maintenance of the neural stem cells (neuroblasts) and the differentiation of their progeny. Despite notable advances over the last two decades, neurogenesis in other arthropod groups remains by comparison less well understood, hampering finer resolution of evolutionary cell type transformations and changes in the genetic regulatory network in some branches of the arthropod tree of life. Although the neurogenic cellular machinery in malacostracan crustaceans is well described morphologically, its genetic molecular characterization is pending. To address this, we established an in situ hybridization protocol for the crayfish Procambarus virginalis and studied embryonic expression patterns of a suite of key genes, encompassing three SoxB group transcription factors, two achaete-scute homologs, a Snail family member, the differentiation determinants Prospero and Brain tumor, and the neuron marker Elav. We document cell type expression patterns with notable similarities to insects and branchiopod crustaceans, lending further support to the homology of hexapod-crustacean neuroblasts and their cell lineages. Remarkably, in the crayfish head region, cell emigration from the neuroectoderm coupled with gene expression data points to a neuroblast-independent initial phase of brain neurogenesis. Further, SoxB group expression patterns suggest an involvement of Dichaete in segmentation, in concordance with insects. Our target gene set is a promising starting point for further embryonic studies, as well as for the molecular genetic characterization of subregions and cell types in the neurogenic systems in the adult crayfish brain.
Collapse
Affiliation(s)
- Georg Brenneis
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts, USA.,Zoologisches Institut und Museum, Universität Greifswald, Greifswald, Germany
| | - Martin Schwentner
- Naturhistorisches Museum Wien, Vienna, Austria.,Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Gonzalo Giribet
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Barbara S Beltz
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts, USA
| |
Collapse
|
19
|
Climent-Cantó P, Carbonell A, Tamirisa S, Henn L, Pérez-Montero S, Boros IM, Azorín F. The tumour suppressor brain tumour (Brat) regulates linker histone dBigH1 expression in the Drosophila female germline and the early embryo. Open Biol 2021; 11:200408. [PMID: 33947246 PMCID: PMC8097206 DOI: 10.1098/rsob.200408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Linker histones H1 are essential chromatin components that exist as multiple developmentally regulated variants. In metazoans, specific H1s are expressed during germline development in a tightly regulated manner. However, the mechanisms governing their stage-dependent expression are poorly understood. Here, we address this question in Drosophila, which encodes for a single germline-specific dBigH1 linker histone. We show that during female germline lineage differentiation, dBigH1 is expressed in germ stem cells and cystoblasts, becomes silenced during transit-amplifying (TA) cystocytes divisions to resume expression after proliferation stops and differentiation starts, when it progressively accumulates in the oocyte. We find that dBigH1 silencing during TA divisions is post-transcriptional and depends on the tumour suppressor Brain tumour (Brat), an essential RNA-binding protein that regulates mRNA translation and stability. Like other oocyte-specific variants, dBigH1 is maternally expressed during early embryogenesis until it is replaced by somatic dH1 at the maternal-to-zygotic transition (MZT). Brat also mediates dBigH1 silencing at MZT. Finally, we discuss the situation in testes, where Brat is not expressed, but dBigH1 is translationally silenced too.
Collapse
Affiliation(s)
- Paula Climent-Cantó
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Albert Carbonell
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Srividya Tamirisa
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Laszlo Henn
- Institute of Biochemistry, Biological Research Centre of Szeged, Szeged 6726, Hungary
| | - Salvador Pérez-Montero
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| | - Imre M Boros
- Institute of Biochemistry, Biological Research Centre of Szeged, Szeged 6726, Hungary.,Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, Szeged 6726, Hungary
| | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona 08028, Spain.,Institute for Research in Biomedicine, IRB Barcelona, The Barcelona Institute for Science and Technology, Barcelona 08028, Spain
| |
Collapse
|
20
|
Chen R, Hou Y, Connell M, Zhu S. Homeodomain protein Six4 prevents the generation of supernumerary Drosophila type II neuroblasts and premature differentiation of intermediate neural progenitors. PLoS Genet 2021; 17:e1009371. [PMID: 33556050 PMCID: PMC7895384 DOI: 10.1371/journal.pgen.1009371] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 02/19/2021] [Accepted: 01/15/2021] [Indexed: 11/19/2022] Open
Abstract
In order to boost the number and diversity of neurons generated from neural stem cells, intermediate neural progenitors (INPs) need to maintain their homeostasis by avoiding both dedifferentiation and premature differentiation. Elucidating how INPs maintain homeostasis is critical for understanding the generation of brain complexity and various neurological diseases resulting from defects in INP development. Here we report that Six4 expressed in Drosophila type II neuroblast (NB) lineages prevents the generation of supernumerary type II NBs and premature differentiation of INPs. We show that loss of Six4 leads to supernumerary type II NBs likely due to dedifferentiation of immature INPs (imINPs). We provide data to further demonstrate that Six4 inhibits the expression and activity of PntP1 in imINPs in part by forming a trimeric complex with Earmuff and PntP1. Furthermore, knockdown of Six4 exacerbates the loss of INPs resulting from the loss of PntP1 by enhancing ectopic Prospero expression in imINPs, suggesting that Six4 is also required for preventing premature differentiation of INPs. Taken together, our work identified a novel transcription factor that likely plays important roles in maintaining INP homeostasis. Intermediate neural progenitors (INPs) are descendants of neural stem cells that can proliferate for a short term to amplify the number of nerve cells generated in the brain. INPs play critical roles in determining how big and complex a brain can grow. To perform their function, INPs need to maintain their own population and must not adopt the identity of neural stem cells, a process called dedifferentiation, or acquire the fate of their own daughter cells and stop proliferation too soon, a process called premature differentiation. However, how INPs avoid dedifferentiation and premature differentiation is not fully understood. In this study, we identified a protein called Six4 as a novel factor that plays important roles in preventing the generation of extra neural stem cells and premature differentiation of INPs in developing fruit fly brains. We described how Six4 functionally and physically interacts with other factors that are involved in regulating INP cell fate specification. Our work provides novel insights into the mechanisms regulating INP development and could have important implications in understanding how complex brains are generated during normal development and how abnormal brain development or brain tumor can occur when INPs fail to avoid premature differentiation or dedifferentiation.
Collapse
Affiliation(s)
- Rui Chen
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Yanjun Hou
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Marisa Connell
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
| | - Sijun Zhu
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, United States of America
- * E-mail:
| |
Collapse
|
21
|
Magadi SS, Voutyraki C, Anagnostopoulos G, Zacharioudaki E, Poutakidou IK, Efraimoglou C, Stapountzi M, Theodorou V, Nikolaou C, Koumbanakis KA, Fullard JF, Delidakis C. Dissecting Hes-centred transcriptional networks in neural stem cell maintenance and tumorigenesis in Drosophila. Development 2020; 147:147/22/dev191544. [PMID: 33229432 DOI: 10.1242/dev.191544] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 10/05/2020] [Indexed: 01/26/2023]
Abstract
Neural stem cells divide during embryogenesis and juvenile life to generate the entire complement of neurons and glia in the nervous system of vertebrates and invertebrates. Studies of the mechanisms controlling the fine balance between neural stem cells and more differentiated progenitors have shown that, in every asymmetric cell division, progenitors send a Delta-Notch signal to their sibling stem cells. Here, we show that excessive activation of Notch or overexpression of its direct targets of the Hes family causes stem-cell hyperplasias in the Drosophila larval central nervous system, which can progress to malignant tumours after allografting to adult hosts. We combined transcriptomic data from these hyperplasias with chromatin occupancy data for Dpn, a Hes transcription factor, to identify genes regulated by Hes factors in this process. We show that the Notch/Hes axis represses a cohort of transcription factor genes. These are excluded from the stem cells and promote early differentiation steps, most likely by preventing the reversion of immature progenitors to a stem-cell fate. We describe the impact of two of these 'anti-stemness' factors, Zfh1 and Gcm, on Notch/Hes-triggered tumorigenesis.
Collapse
Affiliation(s)
- Srivathsa S Magadi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Chrysanthi Voutyraki
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Gerasimos Anagnostopoulos
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Evanthia Zacharioudaki
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Ioanna K Poutakidou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Christina Efraimoglou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Margarita Stapountzi
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Vasiliki Theodorou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Christoforos Nikolaou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Konstantinos A Koumbanakis
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece.,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - John F Fullard
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece
| | - Christos Delidakis
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 70013 Heraklion, Crete, Greece .,Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| |
Collapse
|
22
|
Kurihara M, Takarada K, Inoue YH. Enhancement of leukemia-like phenotypes in Drosophila mxc mutant larvae due to activation of the RAS-MAP kinase cascade possibly via down-regulation of DE-cadherin. Genes Cells 2020; 25:757-769. [PMID: 33012036 DOI: 10.1111/gtc.12811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 01/10/2023]
Abstract
Loss of mxc gene function in mature hemocytes of Drosophila mxcmbn1 mutant results in malignant hyperplasia in larval hematopoietic tissues termed lymph glands (LGs) owing to over-proliferation of immature cells. This is a useful model for genetic analyses of leukemia progression. To identify other mutations that deteriorate the hyperplasia, we aimed to investigate whether hyper-activation of common signaling cascade enabled to enhance the phenotypes. Ectopic expression of the constitutively active forms of MAPK signaling factors in the mutant increased the hyperplasia and the number of circulating hemocytes, resulting in the production of LG fragments. The LG phenotype was related to the reduced DE-cadherin level in the mutants. Depletion of Drosophila MCRIP, involved in MAPK-induced silencing of cadherin gene expression, exhibited a similar enhancement of the mxcmbn1 phenotypes. Furthermore, expression of MMP1 proteinase that cleaves the extracellular matrix proteins increased in the mutant larvae harboring MAPK cascade activation. Depletion of Mmp1 and that of pnt (required for Mmp1 expression) suppressed the LG hyperplasia. Hence, we speculated that reduction in DE-cadherin level by either down-regulation of MCRIP or up-regulation of MMP1 was involved in the progression of the tumor phenotype. Our findings can contribute to understanding the mechanism underlying human leukemia progression.
Collapse
Affiliation(s)
- Masanori Kurihara
- Department of Insect Biomedical Research, Center for Advanced Insect Research Promotion, Kyoto Institute of Technology, Matsugasaki, Kyoto, Japan
| | - Kazuki Takarada
- Department of Insect Biomedical Research, Center for Advanced Insect Research Promotion, Kyoto Institute of Technology, Matsugasaki, Kyoto, Japan
| | - Yoshihiro H Inoue
- Department of Insect Biomedical Research, Center for Advanced Insect Research Promotion, Kyoto Institute of Technology, Matsugasaki, Kyoto, Japan
| |
Collapse
|
23
|
Bonnay F, Veloso A, Steinmann V, Köcher T, Abdusselamoglu MD, Bajaj S, Rivelles E, Landskron L, Esterbauer H, Zinzen RP, Knoblich JA. Oxidative Metabolism Drives Immortalization of Neural Stem Cells during Tumorigenesis. Cell 2020; 182:1490-1507.e19. [PMID: 32916131 DOI: 10.1016/j.cell.2020.07.039] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 06/24/2020] [Accepted: 07/28/2020] [Indexed: 01/04/2023]
Abstract
Metabolic reprogramming is a key feature of many cancers, but how and when it contributes to tumorigenesis remains unclear. Here we demonstrate that metabolic reprogramming induced by mitochondrial fusion can be rate-limiting for immortalization of tumor-initiating cells (TICs) and trigger their irreversible dedication to tumorigenesis. Using single-cell transcriptomics, we find that Drosophila brain tumors contain a rapidly dividing stem cell population defined by upregulation of oxidative phosphorylation (OxPhos). We combine targeted metabolomics and in vivo genetic screening to demonstrate that OxPhos is required for tumor cell immortalization but dispensable in neural stem cells (NSCs) giving rise to tumors. Employing an in vivo NADH/NAD+ sensor, we show that NSCs precisely increase OxPhos during immortalization. Blocking OxPhos or mitochondrial fusion stalls TICs in quiescence and prevents tumorigenesis through impaired NAD+ regeneration. Our work establishes a unique connection between cellular metabolism and immortalization of tumor-initiating cells.
Collapse
Affiliation(s)
- François Bonnay
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria
| | - Ana Veloso
- Systems Biology of Neurogenesis, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Victoria Steinmann
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria
| | - Thomas Köcher
- Vienna Biocenter Core Facilities (VBCF), 1030 Vienna, Austria
| | | | - Sunanjay Bajaj
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria
| | - Elisa Rivelles
- Department of Laboratory Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Lisa Landskron
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria
| | - Harald Esterbauer
- Department of Laboratory Medicine, Medical University of Vienna, 1090 Vienna, Austria
| | - Robert P Zinzen
- Systems Biology of Neurogenesis, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria.
| |
Collapse
|
24
|
Connacher RP, Goldstrohm AC. Molecular and biological functions of TRIM-NHL RNA-binding proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1620. [PMID: 32738036 DOI: 10.1002/wrna.1620] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 01/02/2023]
Abstract
The TRIM-NHL family of proteins shares a conserved domain architecture and play crucial roles in stem cell biology, fertility, and development. This review synthesizes new insights that have revolutionized our understanding of the molecular and biological functions of TRIM-NHL proteins. Multiple TRIM-NHLs have been shown to bind specific RNA sequences and structures. X-ray crystal structures of TRIM-NHL proteins in complex with RNA ligands reveal versatile modes of RNA recognition by the NHL domain. Functional and genetic analyses show that TRIM-NHL RNA-binding proteins negatively regulate the protein expression from the target mRNAs that they bind. This repressive activity plays a crucial role in controlling stem cell fate in the developing brain and differentiating germline. To highlight these paradigms, we focus on several of the most-extensively studied TRIM-NHL proteins, specifically Drosophila and vertebrate TRIM71, among others. Brat is essential for development and regulates key target mRNAs to control differentiation of germline and neural stem cells. TRIM71 is also required for development and promotes stem cell proliferation while antagonizing differentiation. Moreover, TRIM71 can be utilized to help reprogram fibroblasts into induced pluripotent stem cells. Recently discovered mutations in TRIM71 cause the neurodevelopmental disease congenital hydrocephalus and emphasize the importance of its RNA-binding function in brain development. Further relevance of TRIM71 to disease pathogenesis comes from evidence linking it to several types of cancer, including liver and testicular cancer. Collectively, these advances demonstrate a primary role for TRIM-NHL proteins in the post-transcriptional regulation of gene expression in crucial biological processes. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Translation Regulation RNA Turnover and Surveillance > Regulation of RNA Stability.
Collapse
Affiliation(s)
- Robert P Connacher
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | | |
Collapse
|
25
|
Williams FP, Haubrich K, Perez-Borrajero C, Hennig J. Emerging RNA-binding roles in the TRIM family of ubiquitin ligases. Biol Chem 2020; 400:1443-1464. [PMID: 31120853 DOI: 10.1515/hsz-2019-0158] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/11/2019] [Indexed: 12/14/2022]
Abstract
TRIM proteins constitute a large, diverse and ancient protein family which play a key role in processes including cellular differentiation, autophagy, apoptosis, DNA repair, and tumour suppression. Mostly known and studied through the lens of their ubiquitination activity as E3 ligases, it has recently emerged that many of these proteins are involved in direct RNA binding through their NHL or PRY/SPRY domains. We summarise the current knowledge concerning the mechanism of RNA binding by TRIM proteins and its biological role. We discuss how RNA-binding relates to their previously described functions such as E3 ubiquitin ligase activity, and we will consider the potential role of enrichment in membrane-less organelles.
Collapse
Affiliation(s)
- Felix Preston Williams
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Kevin Haubrich
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Cecilia Perez-Borrajero
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany, e-mail:
| |
Collapse
|
26
|
Blatt P, Martin ET, Breznak SM, Rangan P. Post-transcriptional gene regulation regulates germline stem cell to oocyte transition during Drosophila oogenesis. Curr Top Dev Biol 2019; 140:3-34. [PMID: 32591078 DOI: 10.1016/bs.ctdb.2019.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
During oogenesis, several developmental processes must be traversed to ensure effective completion of gametogenesis including, stem cell maintenance and asymmetric division, differentiation, mitosis and meiosis, and production of maternally contributed mRNAs, making the germline a salient model for understanding how cell fate transitions are mediated. Due to silencing of the genome during meiotic divisions, there is little instructive transcription, barring a few examples, to mediate these critical transitions. In Drosophila, several layers of post-transcriptional regulation ensure that the mRNAs required for these processes are expressed in a timely manner and as needed during germline differentiation. These layers of regulation include alternative splicing, RNA modification, ribosome production, and translational repression. Many of the molecules and pathways involved in these regulatory activities are conserved from Drosophila to humans making the Drosophila germline an elegant model for studying the role of post-transcriptional regulation during stem cell differentiation and meiosis.
Collapse
Affiliation(s)
- Patrick Blatt
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, United States; University at Albany SUNY, Albany, NY, United States
| | - Elliot T Martin
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, United States; University at Albany SUNY, Albany, NY, United States
| | - Shane M Breznak
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, United States; University at Albany SUNY, Albany, NY, United States
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, United States; University at Albany SUNY, Albany, NY, United States.
| |
Collapse
|
27
|
Ventos-Alfonso A, Ylla G, Belles X. Zelda and the maternal-to-zygotic transition in cockroaches. FEBS J 2019; 286:3206-3221. [PMID: 30993896 DOI: 10.1111/febs.14856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 03/22/2019] [Accepted: 04/15/2019] [Indexed: 12/22/2022]
Abstract
In the endopterygote Drosophila melanogaster, Zelda is an activator of the zygotic genome during the maternal-to-zygotic transition (MZT). Zelda binds cis-regulatory elements (TAGteam heptamers), making chromatin accessible for gene transcription. Zelda has been studied in other endopterygotes: Apis mellifera and Tribolium castaneum, and the paraneopteran Rhodnius prolixus. We studied Zelda in the cockroach Blattella germanica, a hemimetabolan, short germ-band, and polyneopteran species. B. germanica Zelda has the complete set of functional domains, which is typical of species displaying ancestral features concerning embryogenesis. Interestingly, we found D. melanogaster TAGteam heptamers in the B. germanica genome. The canonical one, CAGGTAG, is present at a similar proportion in the genome of these two species and in the genome of other insects, suggesting that the genome admits as many CAGGTAG motifs as its length allows. Zelda-depleted embryos of B. germanica show defects involving blastoderm formation and abdomen development, and genes contributing to these processes are down-regulated. We conclude that in B. germanica, Zelda strictly activates the zygotic genome, within the MZT, a role conserved in more derived endopterygote insects. In B. germanica, zelda is expressed during MZT, whereas in D. melanogaster and T. castaneum it is expressed beyond this transition. In these species and A. mellifera, Zelda has functions even in postembryonic development. The expansion of zelda expression beyond the MZT in endopterygotes might be related with the evolutionary innovation of holometabolan metamorphosis. DATABASES: The RNA-seq datasets of B. germanica, D. melanogaster, and T. castaneum are accessible at the GEO databases GSE99785, GSE18068, GSE63770, and GSE84253. In addition, the RNA-seq library from T. castaneum adult females is available at SRA: SRX021963. The B. germanica reference genome is available as BioProject PRJNA203136.
Collapse
Affiliation(s)
- Alba Ventos-Alfonso
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Guillem Ylla
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Xavier Belles
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| |
Collapse
|
28
|
Mirkovic M, Guilgur LG, Tavares A, Passagem-Santos D, Oliveira RA. Induced aneuploidy in neural stem cells triggers a delayed stress response and impairs adult life span in flies. PLoS Biol 2019; 17:e3000016. [PMID: 30794535 PMCID: PMC6402706 DOI: 10.1371/journal.pbio.3000016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 03/06/2019] [Accepted: 01/31/2019] [Indexed: 02/07/2023] Open
Abstract
Studying aneuploidy during organism development has strong limitations because chronic mitotic perturbations used to generate aneuploidy usually result in lethality. We developed a genetic tool to induce aneuploidy in an acute and time-controlled manner during Drosophila development. This is achieved by reversible depletion of cohesin, a key molecule controlling mitotic fidelity. Larvae challenged with aneuploidy hatch into adults with severe motor defects shortening their life span. Neural stem cells, despite being aneuploid, display a delayed stress response and continue proliferating, resulting in the rapid appearance of chromosomal instability, a complex array of karyotypes, and cellular abnormalities. Notably, when other brain-cell lineages are forced to self-renew, aneuploidy-associated stress response is significantly delayed. Protecting only the developing brain from induced aneuploidy is sufficient to rescue motor defects and adult life span, suggesting that neural tissue is the most ill-equipped to deal with developmental aneuploidy.
Collapse
|
29
|
Mir M, Stadler MR, Ortiz SA, Hannon CE, Harrison MM, Darzacq X, Eisen MB. Dynamic multifactor hubs interact transiently with sites of active transcription in Drosophila embryos. eLife 2018; 7:e40497. [PMID: 30589412 PMCID: PMC6307861 DOI: 10.7554/elife.40497] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/30/2018] [Indexed: 12/12/2022] Open
Abstract
The regulation of transcription requires the coordination of numerous activities on DNA, yet how transcription factors mediate these activities remains poorly understood. Here, we use lattice light-sheet microscopy to integrate single-molecule and high-speed 4D imaging in developing Drosophila embryos to study the nuclear organization and interactions of the key transcription factors Zelda and Bicoid. In contrast to previous studies suggesting stable, cooperative binding, we show that both factors interact with DNA with surprisingly high off-rates. We find that both factors form dynamic subnuclear hubs, and that Bicoid binding is enriched within Zelda hubs. Remarkably, these hubs are both short lived and interact only transiently with sites of active Bicoid-dependent transcription. Based on our observations, we hypothesize that, beyond simply forming bridges between DNA and the transcription machinery, transcription factors can organize other proteins into hubs that transiently drive multiple activities at their gene targets. Editorial note This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
Collapse
Affiliation(s)
- Mustafa Mir
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Michael R Stadler
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Stephan A Ortiz
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Colleen E Hannon
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Melissa M Harrison
- Department of Biomolecular ChemistryUniversity of Wisconsin–MadisonMadisonUnited States
| | - Xavier Darzacq
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Michael B Eisen
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
| |
Collapse
|
30
|
Komori H, Golden KL, Kobayashi T, Kageyama R, Lee CY. Multilayered gene control drives timely exit from the stem cell state in uncommitted progenitors during Drosophila asymmetric neural stem cell division. Genes Dev 2018; 32:1550-1561. [PMID: 30463902 PMCID: PMC6295162 DOI: 10.1101/gad.320333.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/09/2018] [Indexed: 12/23/2022]
Abstract
Self-renewal genes maintain stem cells in an undifferentiated state by preventing the commitment to differentiate. Robust inactivation of self-renewal gene activity following asymmetric stem cell division allows uncommitted stem cell progeny to exit from an undifferentiated state and initiate the commitment to differentiate. Nonetheless, how self-renewal gene activity at mRNA and protein levels becomes synchronously terminated in uncommitted stem cell progeny is unclear. We demonstrate that a multilayered gene regulation system terminates self-renewal gene activity at all levels in uncommitted stem cell progeny in the fly neural stem cell lineage. We found that the RNA-binding protein Brain tumor (Brat) targets the transcripts of a self-renewal gene, deadpan (dpn), for decay by recruiting the deadenylation machinery to the 3' untranslated region (UTR). Furthermore, we identified a nuclear protein, Insensible, that complements Cullin-mediated proteolysis to robustly inactivate Dpn activity by limiting the level of active Dpn through protein sequestration. The synergy between post-transcriptional and transcriptional control of self-renewal genes drives timely exit from the stem cell state in uncommitted progenitors. Our proposed multilayered gene regulation system could be broadly applicable to the control of exit from stemness in all stem cell lineages.
Collapse
Affiliation(s)
- Hideyuki Komori
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Krista L Golden
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Taeko Kobayashi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Shogoin-Kawahara, Sakyo-ku, Kyoto 606-8507, Japan
| | - Ryoichiro Kageyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Shogoin-Kawahara, Sakyo-ku, Kyoto 606-8507, Japan
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA.,Division of Genetic Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| |
Collapse
|
31
|
Olesnicky EC, Wright EG. Drosophila as a Model for Assessing the Function of RNA-Binding Proteins during Neurogenesis and Neurological Disease. J Dev Biol 2018; 6:E21. [PMID: 30126171 PMCID: PMC6162566 DOI: 10.3390/jdb6030021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/15/2018] [Accepted: 08/15/2018] [Indexed: 12/16/2022] Open
Abstract
An outstanding question in developmental neurobiology is how RNA processing events contribute to the regulation of neurogenesis. RNA processing events are increasingly recognized as playing fundamental roles in regulating multiple developmental events during neurogenesis, from the asymmetric divisions of neural stem cells, to the generation of complex and diverse neurite morphologies. Indeed, both asymmetric cell division and neurite morphogenesis are often achieved by mechanisms that generate asymmetric protein distributions, including post-transcriptional gene regulatory mechanisms such as the transport of translationally silent messenger RNAs (mRNAs) and local translation of mRNAs within neurites. Additionally, defects in RNA splicing have emerged as a common theme in many neurodegenerative disorders, highlighting the importance of RNA processing in maintaining neuronal circuitry. RNA-binding proteins (RBPs) play an integral role in splicing and post-transcriptional gene regulation, and mutations in RBPs have been linked with multiple neurological disorders including autism, dementia, amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), Fragile X syndrome (FXS), and X-linked intellectual disability disorder. Despite their widespread nature and roles in neurological disease, the molecular mechanisms and networks of regulated target RNAs have been defined for only a small number of specific RBPs. This review aims to highlight recent studies in Drosophila that have advanced our knowledge of how RBP dysfunction contributes to neurological disease.
Collapse
Affiliation(s)
- Eugenia C Olesnicky
- Department of Biology, University of Colorado Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918, USA.
| | - Ethan G Wright
- Department of Biology, University of Colorado Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918, USA.
| |
Collapse
|
32
|
Nunes da Fonseca R, Venancio TM. Maternal or zygotic: Unveiling the secrets of the Pancrustacea transcription factor zelda. PLoS Genet 2018; 14:e1007201. [PMID: 29494591 PMCID: PMC5832190 DOI: 10.1371/journal.pgen.1007201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Rodrigo Nunes da Fonseca
- Laboratório Integrado de Bioquímica Hatisaburo Masuda, Núcleo em Ecologia e Desenvolvimento SócioAmbiental de Macaé (NUPEM), Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular—INCT-EM, Brazil
- * E-mail: (RNdF); (TMV)
| | - Thiago M. Venancio
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular—INCT-EM, Brazil
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Rio de Janeiro, Brazil
- * E-mail: (RNdF); (TMV)
| |
Collapse
|
33
|
Reichardt I, Bonnay F, Steinmann V, Loedige I, Burkard TR, Meister G, Knoblich JA. The tumor suppressor Brat controls neuronal stem cell lineages by inhibiting Deadpan and Zelda. EMBO Rep 2017; 19:102-117. [PMID: 29191977 DOI: 10.15252/embr.201744188] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 10/31/2017] [Accepted: 11/10/2017] [Indexed: 11/09/2022] Open
Abstract
The TRIM-NHL protein Brain tumor (Brat) acts as a tumor suppressor in the Drosophila brain, but how it suppresses tumor formation is not completely understood. Here, we combine temperature-controlled brat RNAi with transcriptome analysis to identify the immediate Brat targets in Drosophila neuroblasts. Besides the known target Deadpan (Dpn), our experiments identify the transcription factor Zelda (Zld) as a critical target of Brat. Our data show that Zld is expressed in neuroblasts and required to allow re-expression of Dpn in transit-amplifying intermediate neural progenitors. Upon neuroblast division, Brat is enriched in one daughter cell where its NHL domain directly binds to specific motifs in the 3'UTR of dpn and zld mRNA to mediate their degradation. In brat mutants, both Dpn and Zld continue to be expressed, but inhibition of either transcription factor prevents tumorigenesis. Our genetic and biochemical data indicate that Dpn inhibition requires higher Brat levels than Zld inhibition and suggest a model where stepwise post-transcriptional inhibition of distinct factors ensures sequential generation of fates in a stem cell lineage.
Collapse
Affiliation(s)
- Ilka Reichardt
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - François Bonnay
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Victoria Steinmann
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Inga Loedige
- Laboratory for RNA Biology, Biochemistry Center Regensburg (BZR), University of Regensburg, Regensburg, Germany
| | - Thomas R Burkard
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Gunter Meister
- Laboratory for RNA Biology, Biochemistry Center Regensburg (BZR), University of Regensburg, Regensburg, Germany
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| |
Collapse
|