1
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Cullen G, Gilligan JB, Guhlin JG, Dearden PK. Germline progenitors and oocyte production in the honeybee queen ovary. Genetics 2023; 225:iyad138. [PMID: 37487025 PMCID: PMC10471204 DOI: 10.1093/genetics/iyad138] [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: 04/26/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/26/2023] Open
Abstract
Understanding the reproduction of honeybee queens is crucial to support populations of this economically important insect. Here we examine the structure of the honeybee ovary to determine the nature of the germline progenitors in the ovary. Using a panel of marker genes that mark somatic or germline tissue in other insects we determine which cells in the honeybee ovary are somatic and which germline. We examine patterns of cell division and demonstrate that, unlike Drosophila, there is no evidence of single germline stem cells that provide the germline in honeybees. Germline progenitors are clustered in groups of 8 cells, joined by a polyfusome, and collections of these, in each ovariole, appear to maintain the germline during reproduction. We also show that these 8-cell clusters can divide and that their division occurs such that the numbers of germline progenitors are relatively constant over the reproductive life of queen honeybees. This information helps us to understand the diversity of structures in insect reproduction, and provide information to better support honeybee reproduction.
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Affiliation(s)
- Georgia Cullen
- Laboratory for Evolution and Development, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
| | - Joshua B Gilligan
- Laboratory for Evolution and Development, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
- Biological Heritage National Science Challenge, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
| | - Joseph G Guhlin
- Laboratory for Evolution and Development, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
- Genomics Aotearoa, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
| | - Peter K Dearden
- Laboratory for Evolution and Development, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
- Biological Heritage National Science Challenge, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
- Genomics Aotearoa, Biochemistry Department, University of Otago, Dunedin, 9054, Aotearoa-New Zealand
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2
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Galasso A, Xu DC, Hill C, Iakovleva D, Stefana MI, Baena‐Lopez LA. Non-apoptotic caspase activation ensures the homeostasis of ovarian somatic stem cells. EMBO Rep 2023; 24:e51716. [PMID: 37039000 PMCID: PMC10240206 DOI: 10.15252/embr.202051716] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/22/2023] [Accepted: 03/14/2023] [Indexed: 04/12/2023] Open
Abstract
Current evidence has associated caspase activation with the regulation of basic cellular functions without causing apoptosis. Malfunction of non-apoptotic caspase activities may contribute to specific neurological disorders, metabolic diseases, autoimmune conditions and cancers. However, our understanding of non-apoptotic caspase functions remains limited. Here, we show that non-apoptotic caspase activation prevents the intracellular accumulation of the Patched receptor in autophagosomes and the subsequent Patched-dependent induction of autophagy in Drosophila follicular stem cells. These events ultimately sustain Hedgehog signalling and the physiological properties of ovarian somatic stem cells and their progeny under moderate thermal stress. Importantly, our key findings are partially conserved in ovarian somatic cells of human origin. These observations attribute to caspases a pro-survival role under certain cellular conditions.
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Affiliation(s)
- Alessia Galasso
- Faculty of Medicine CentreImperial College London, South Kensington CampusLondonUK
| | - Derek Cui Xu
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
| | - Claire Hill
- School of Medicine, Dentistry and Biomedical SciencesQueen's University Belfast MedicineBelfastUK
| | - Daria Iakovleva
- Center for Regenerative MedicineUniversity of EdinburghEdinburghUK
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3
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Chatterjee D, Cong F, Wang XF, Machado Costa CA, Huang YC, Deng WM. Cell polarity opposes Jak/STAT-mediated Escargot activation that drives intratumor heterogeneity in a Drosophila tumor model. Cell Rep 2023; 42:112061. [PMID: 36709425 PMCID: PMC10374876 DOI: 10.1016/j.celrep.2023.112061] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 11/28/2022] [Accepted: 01/18/2023] [Indexed: 01/30/2023] Open
Abstract
In proliferating neoplasms, microenvironment-derived selective pressures promote tumor heterogeneity by imparting diverse capacities for growth, differentiation, and invasion. However, what makes a tumor cell respond to signaling cues differently from a normal cell is not well understood. In the Drosophila ovarian follicle cells, apicobasal-polarity loss induces heterogeneous epithelial multilayering. When exacerbated by oncogenic-Notch expression, this multilayer displays an increased consistency in the occurrence of morphologically distinguishable cells adjacent to the polar follicle cells. Polar cells release the Jak/STAT ligand Unpaired (Upd), in response to which neighboring polarity-deficient cells exhibit a precursor-like transcriptomic state. Among the several regulons active in these cells, we could detect and further validate the expression of Snail family transcription factor Escargot (Esg). We also ascertain a similar relationship between Upd and Esg in normally developing ovaries, where establishment of polarity determines early follicular differentiation. Overall, our results indicate that epithelial-cell polarity acts as a gatekeeper against microenvironmental selective pressures that drive heterogeneity.
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Affiliation(s)
- Deeptiman Chatterjee
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Fei Cong
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Xian-Feng Wang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Caique Almeida Machado Costa
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Yi-Chun Huang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Wu-Min Deng
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA.
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4
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Lee EH, Zinshteyn D, Miglo F, Wang MQ, Reinach J, Chau CM, Grosstephan JM, Correa I, Costa K, Vargas A, Johnson A, Longo SM, Alexander JI, O'Reilly AM. Sequential events during the quiescence to proliferation transition establish patterns of follicle cell differentiation in the Drosophila ovary. Biol Open 2023; 12:bio059625. [PMID: 36524613 PMCID: PMC9867896 DOI: 10.1242/bio.059625] [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: 09/06/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Stem cells cycle between periods of quiescence and proliferation to promote tissue health. In Drosophila ovaries, quiescence to proliferation transitions of follicle stem cells (FSCs) are exquisitely feeding-dependent. Here, we demonstrate feeding-dependent induction of follicle cell differentiation markers, eyes absent (Eya) and castor (Cas) in FSCs, a patterning process that does not depend on proliferation induction. Instead, FSCs extend micron-scale cytoplasmic projections that dictate Eya-Cas patterning. We identify still life and sickie as necessary and sufficient for FSC projection growth and Eya-Cas induction. Our results suggest that sequential, interdependent events establish long-term differentiation patterns in follicle cell precursors, independently of FSC proliferation induction.
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Affiliation(s)
- Eric H. Lee
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Daniel Zinshteyn
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Fred Miglo
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Melissa Q. Wang
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Jessica Reinach
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Cindy M. Chau
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | | | - Iliana Correa
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Kelly Costa
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Alberto Vargas
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Aminah Johnson
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Sheila M. Longo
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Drexel University College of Medicine, Molecular and Cellular Biology and Genetics Graduate Program, Philadelphia, PA 19129, USA
| | - Jennifer I. Alexander
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Alana M. O'Reilly
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Immersion Science Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Drexel University College of Medicine, Molecular and Cellular Biology and Genetics Graduate Program, Philadelphia, PA 19129, USA
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5
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Nellas I, Iyer KV, Iglesias‐Artola JM, Pippel M, Nadler A, Eaton S, Dye NA. Hedgehog signaling can enhance glycolytic ATP production in the Drosophila wing disc. EMBO Rep 2022; 23:e54025. [PMID: 36134875 PMCID: PMC9638854 DOI: 10.15252/embr.202154025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 08/02/2022] [Accepted: 08/22/2022] [Indexed: 09/08/2024] Open
Abstract
Adenosine triphosphate (ATP) production and utilization is critically important for animal development. How these processes are regulated in space and time during tissue growth remains largely unclear. We used a FRET-based sensor to dynamically monitor ATP levels across a growing tissue, using the Drosophila larval wing disc. Although steady-state levels of ATP are spatially uniform across the wing pouch, inhibiting oxidative phosphorylation reveals spatial differences in metabolic behavior, whereby signaling centers at compartment boundaries produce more ATP from glycolysis than the rest of the tissue. Genetic perturbations indicate that the conserved Hedgehog signaling pathway can enhance ATP production by glycolysis. Collectively, our work suggests the existence of a homeostatic feedback loop between Hh signaling and glycolysis, advancing our understanding of the connection between conserved developmental patterning genes and ATP production during animal tissue development.
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Affiliation(s)
- Ioannis Nellas
- Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
- Excellence Cluster, Physics of LifeTechnische Universität DresdenDresdenGermany
| | - K Venkatesan Iyer
- Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
- Department of Mechanical EngineeringIndian Institute of ScienceBangaloreIndia
| | | | - Martin Pippel
- Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
- Center for Systems Biology DresdenDresdenGermany
| | - André Nadler
- Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
| | - Suzanne Eaton
- Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
- Excellence Cluster, Physics of LifeTechnische Universität DresdenDresdenGermany
- Center for Systems Biology DresdenDresdenGermany
- Biotechnologisches ZentrumTechnische Universität DresdenDresdenGermany
| | - Natalie A Dye
- Max Planck Institute for Molecular Cell Biology and GeneticsDresdenGermany
- Excellence Cluster, Physics of LifeTechnische Universität DresdenDresdenGermany
- Mildred Scheel Nachwuchszentrum (MSNZ) P2, Medical FacultyTechnische Universität DresdenDresdenGermany
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6
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Eya-controlled affinity between cell lineages drives tissue self-organization during Drosophila oogenesis. Nat Commun 2022; 13:6377. [PMID: 36289235 PMCID: PMC9605976 DOI: 10.1038/s41467-022-33845-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 10/05/2022] [Indexed: 12/25/2022] Open
Abstract
Cooperative morphogenesis of cell lineages underlies the development of functional units and organs. To study mechanisms driving the coordination of lineages, we investigated soma-germline interactions during oogenesis. From invertebrates to vertebrates, oocytes develop as part of a germline cyst that consists of the oocyte itself and so-called nurse cells, which feed the oocyte and are eventually removed. The enveloping somatic cells specialize to facilitate either oocyte maturation or nurse cell removal, which makes it essential to establish the right match between germline and somatic cells. We uncover that the transcriptional regulator Eya, expressed in the somatic lineage, controls bilateral cell-cell affinity between germline and somatic cells in Drosophila oogenesis. Employing functional studies and mathematical modelling, we show that differential affinity and the resulting forces drive somatic cell redistribution over the germline surface and control oocyte growth to match oocyte and nurse cells with their respective somatic cells. Thus, our data demonstrate that differential affinity between cell lineages is sufficient to drive the complex assembly of inter-lineage functional units and underlies tissue self-organization during Drosophila oogenesis.
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7
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Shao TL, Ting RT, Lee MC. Identification of Lsd1-interacting non-coding RNAs as regulators of fly oogenesis. Cell Rep 2022; 40:111294. [PMID: 36044841 DOI: 10.1016/j.celrep.2022.111294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 06/03/2022] [Accepted: 08/10/2022] [Indexed: 11/03/2022] Open
Abstract
Lysine-specific demethylase 1 (Lsd1) plays a key role in balancing cell proliferation and differentiation. Lsd1 has been recently reported to associate with specific long noncoding RNAs (lncRNAs) to account for oncogenic gene expression in cancer cells. However, how lncRNA-Lsd1 interplay affects cell-specific differentiation remains elusive in vivo. Here, through Lsd1 specific RNA immunopecipitation sequencing (RIP-seq) experiments, we identify three long hairpin RNAs as Lsd1-interacting non-coding RNAs (LINRs) from fly ovaries. Knocking out LINR-1 and LINR-2 affects fly egg production, while each of the LINR deletion mutant females produce eggs with reduced hatch rate, indicating important functions of LINRs in supporting oogenesis. At the cellular level, LINR-2 regulates the differentiation of germline stem cells and follicle progenitors likely though modulating the expression and function of Lsd1 in vivo. Our identification of ovarian LINRs presents a physiological example of dynamic lncRNA-Lsd1 interplay that regulates stem cell/progenitor differentiation.
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Affiliation(s)
- Tzu-Ling Shao
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ruei-Teng Ting
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ming-Chia Lee
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan.
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8
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Riparbelli MG, Persico V, Callaini G. Cell-to-Cell Interactions during Early Drosophila Oogenesis: An Ultrastructural Analysis. Cells 2022; 11:cells11172658. [PMID: 36078066 PMCID: PMC9454453 DOI: 10.3390/cells11172658] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/27/2022] Open
Abstract
Drosophila oogenesis requires the subsequent growth of distinct egg chambers each containing a group of sixteen germline cells surrounded by a simple epithelium of follicle cells. The oocyte occupies a posterior position within the germ cells, thus giving a distinct asymmetry to the egg chamber. Although this disposition is critical for the formation of the anterior–posterior axis of the embryo, the interplay between somatic and germ cells during the early stages of oogenesis remains an open question. We uncover by stage 2, when the egg chambers leaved the germarium, some unique spatial interactions between the posterior follicle cells and the oocyte. These interactions are restricted to the surface of the oocyte over the centriole cluster that formed during early oogenesis. Moreover, the posterior follicle cells in front of the oocyte display a convoluted apical membrane with extensive contacts, whereas the other follicle cells have a flat apical surface without obvious surface protrusions. In addition, the germ cells located at the posterior end of the egg chamber have very elongated protrusions that come into contact with each other or with facing follicle cells. These observations point to distinct polarization events during early oogenesis supporting previous molecular data of an inherent asymmetry between the anterior and the posterior regions of the egg chambers.
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9
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Wu Z, Liu JL. CTP synthase does not form cytoophidia in Drosophila interfollicular stalks. Exp Cell Res 2022; 418:113250. [PMID: 35691380 DOI: 10.1016/j.yexcr.2022.113250] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/05/2022] [Accepted: 06/06/2022] [Indexed: 11/26/2022]
Abstract
CTP synthase (CTPS) catalyzes the final step of de novo synthesis of the nucleotide CTP. In 2010, CTPS has been found to form filamentous structures termed cytoophidia in Drosophila follicle cells and germline cells. Subsequently, cytoophidia have been reported in many species across three domains of life: bacteria, eukaryotes and archaea. Forming cytoophidia appears to be a highly conserved and ancient property of CTPS. To our surprise, here we find that polar cells and stalk cells, two specialized types of cells composing Drosophila interfollicular stalks, do not possess obvious cytoophidia. We show that Myc level is low in these two types of cells. Treatment with a glutamine analog, 6-diazo-5-oxo-l-norleucine (DON), increases cytoophidium assembly in main follicle cells, but not in polar cells or stalk cells. Moreover, overexpressing Myc induces cytoophidium formation in stalk cells. When CTPS is overexpressed, cytoophidia can be observed both in stalk cells and polar cells. Our findings provide an interesting paradigm for the in vivo study of cytoophidium assembly and disassembly among different populations of follicle cells.
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Affiliation(s)
- Zheng Wu
- School of Life Science and Technology, ShanghaiTech University, 230 Haike Road, 201210, Shanghai, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, 230 Haike Road, 201210, Shanghai, China; Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3PT, United Kingdom.
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10
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Sood C, Justis VT, Doyle SE, Siegrist SE. Notch signaling regulates neural stem cell quiescence entry and exit in Drosophila. Development 2022; 149:274416. [PMID: 35112131 PMCID: PMC8918809 DOI: 10.1242/dev.200275] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 01/13/2022] [Indexed: 12/18/2022]
Abstract
Stem cells enter and exit quiescence as part of normal developmental programs and to maintain tissue homeostasis in adulthood. Although it is clear that stem cell intrinsic and extrinsic cues, local and systemic, regulate quiescence, it remains unclear whether intrinsic and extrinsic cues coordinate to control quiescence and how cue coordination is achieved. Here, we report that Notch signaling coordinates neuroblast intrinsic temporal programs with extrinsic nutrient cues to regulate quiescence in Drosophila. When Notch activity is reduced, quiescence is delayed or altogether bypassed, with some neuroblasts dividing continuously during the embryonic-to-larval transition. During embryogenesis before quiescence, neuroblasts express Notch and the Notch ligand Delta. After division, Delta is partitioned to adjacent GMC daughters where it transactivates Notch in neuroblasts. Over time, in response to intrinsic temporal cues and increasing numbers of Delta-expressing daughters, neuroblast Notch activity increases, leading to cell cycle exit and consequently, attenuation of Notch pathway activity. Quiescent neuroblasts have low to no active Notch, which is required for exit from quiescence in response to nutrient cues. Thus, Notch signaling coordinates proliferation versus quiescence decisions.
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11
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Vasudevan D, Katow H, Huang HW, Tang G, Ryoo HD. A Protein-trap allele reveals roles for Drosophila ATF4 in photoreceptor degeneration, oogenesis and wing development. Dis Model Mech 2021; 15:273766. [PMID: 34919148 PMCID: PMC8938396 DOI: 10.1242/dmm.049119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 12/08/2021] [Indexed: 11/20/2022] Open
Abstract
Metazoans have evolved various quality control mechanisms to cope with cellular stress inflicted by external and physiological conditions. ATF4 is a major effector of the Integrated Stress Response (ISR), an evolutionarily conserved pathway that mediates adaptation to various cellular stressors. Loss of function of Drosophila ATF4, encoded by the gene cryptocephal (crc), results in lethality during pupal development. The roles of crc in Drosophila disease models and in adult tissue homeostasis thus remain poorly understood. Here, we report that a protein-trap MiMIC insertion in the crc locus generates a crc-GFP fusion protein that allows visualization of crc activity in vivo. This allele also acts as a hypomorphic mutant that uncovers previously unknown roles for crc. Specifically, the crc protein-trap line shows crc-GFP induction in a Drosophila model for Retinitis Pigmentosa (RP). This crc allele renders flies more vulnerable to amino acid deprivation and age-dependent retinal degeneration. These mutants also show defects in wing veins and oocyte maturation. Together, our data reveal previously unknown roles for crc in development, cellular homeostasis and photoreceptor survival.
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Affiliation(s)
- Deepika Vasudevan
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA.,Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Hidetaka Katow
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | | | - Grace Tang
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
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12
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Tatapudy S, Peralta J, Nystul T. Distinct roles of Bendless in regulating FSC niche competition and daughter cell differentiation. Development 2021; 148:dev199630. [PMID: 35020878 PMCID: PMC8645206 DOI: 10.1242/dev.199630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 10/13/2021] [Indexed: 04/05/2024]
Abstract
A major goal in the study of adult stem cells is to understand how cell fates are specified at the proper time and place to facilitate tissue homeostasis. Here, we found that an E2 ubiquitin ligase, Bendless (Ben), has multiple roles in the Drosophila ovarian epithelial follicle stem cell (FSC) lineage. First, Ben is part of the JNK signaling pathway, and we found that it, as well as other JNK pathway genes, are essential for differentiation of FSC daughter cells. Our data suggest that JNK signaling promotes differentiation by suppressing the activation of the EGFR effector, ERK. Also, we found that loss of ben, but not the JNK kinase hemipterous, resulted in an upregulation of hedgehog signaling, increased proliferation and increased niche competition. Lastly, we demonstrate that the hypercompetition phenotype caused by loss of ben is suppressed by decreasing the rate of proliferation or knockdown of the hedgehog pathway effector, Smoothened (Smo). Taken together, our findings reveal a new layer of regulation in which a single gene influences cell signaling at multiple stages of differentiation in the early FSC lineage.
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Affiliation(s)
| | | | - Todd Nystul
- Department of Anatomy and Department of OB/Gyn-RS, University of California, San Francisco, Center for Reproductive Sciences, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, 513 Parnassus Avenue, San Francisco, CA, 94143, USA
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13
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Tidswell ORA, Benton MA, Akam M. The neuroblast timer gene nubbin exhibits functional redundancy with gap genes to regulate segment identity in Tribolium. Development 2021; 148:271199. [PMID: 34351412 PMCID: PMC8406537 DOI: 10.1242/dev.199719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/23/2021] [Indexed: 12/05/2022]
Abstract
The neuroblast timer genes hunchback, Krüppel, nubbin and castor are expressed in temporal sequence in neural stem cells, and in corresponding spatial sequence along the Drosophila blastoderm. As canonical gap genes, hunchback and Krüppel play a crucial role in insect segmentation, but the roles of nubbin and castor in this process remain ambiguous. We have investigated the expression and functions of nubbin and castor during segmentation in the beetle Tribolium. We show that Tc-hunchback, Tc-Krüppel, Tc-nubbin and Tc-castor are expressed sequentially in the segment addition zone, and that Tc-nubbin regulates segment identity redundantly with two previously described gap/gap-like genes, Tc-giant and Tc-knirps. Simultaneous knockdown of Tc-nubbin, Tc-giant and Tc-knirps results in the formation of ectopic legs on abdominal segments. This homeotic transformation is caused by loss of abdominal Hox gene expression, likely due to expanded Tc-Krüppel expression. Our findings support the theory that the neuroblast timer series was co-opted for use in insect segment patterning, and contribute to our growing understanding of the evolution and function of the gap gene network outside of Drosophila. Summary:nubbin and the gap genes knirps and giant redundantly repress Krüppel expression during segmentation. Simultaneous knockdown of all three genes causes ectopic Krüppel expression and loss of abdominal segment identity.
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Affiliation(s)
| | - Matthew A Benton
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Michael Akam
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
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14
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Slaidina M, Gupta S, Banisch TU, Lehmann R. A single-cell atlas reveals unanticipated cell type complexity in Drosophila ovaries. Genome Res 2021; 31:1938-1951. [PMID: 34389661 DOI: 10.1101/gr.274340.120] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 08/09/2021] [Indexed: 11/24/2022]
Abstract
Organ function relies on the spatial organization and functional coordination of numerous cell types. The Drosophila ovary is a widely used model system to study the cellular activities underlying organ function, including stem cell regulation, cell signaling and epithelial morphogenesis. However, the relative paucity of cell type-specific reagents hinders investigation of molecular functions at the appropriate cellular resolution. Here, we used single-cell RNA sequencing to characterize all cell types of the stem cell compartment and early follicles of the Drosophila ovary. We computed transcriptional signatures and identified specific markers for nine states of germ cell differentiation, and 23 somatic cell types and subtypes. We uncovered an unanticipated diversity of escort cells, the somatic cells that directly interact with differentiating germline cysts. Three escort cell subtypes reside in discrete anatomical positions, and express distinct sets of secreted and transmembrane proteins, suggesting that diverse micro-environments support the progressive differentiation of germ cells. Finally, we identified 17 follicle cell subtypes, and characterized their transcriptional profiles. Altogether, we provide a comprehensive resource of gene expression, cell type-specific markers, spatial coordinates and functional predictions for 34 ovarian cell types and subtypes.
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Affiliation(s)
| | - Selena Gupta
- Skirball Institute, NYU Grossman School of Medicine
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15
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Clerbaux LA, Schultz H, Roman-Holba S, Ruan DF, Yu R, Lamb AM, Bommer GT, Kennell JA. The microRNA miR-33 is a pleiotropic regulator of metabolic and developmental processes in Drosophila melanogaster. Dev Dyn 2021; 250:1634-1650. [PMID: 33840153 DOI: 10.1002/dvdy.344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND miR-33 family members are well characterized regulators of cellular lipid levels in mammals. Previous studies have shown that overexpression of miR-33 in Drosophila melanogaster leads to elevated triacylglycerol (TAG) levels in certain contexts. Although loss of miR-33 in flies causes subtle defects in larval and adult ovaries, the effects of miR-33 deficiency on lipid metabolism and other phenotypes impacted by metabolic state have not yet been characterized. RESULTS We found that loss of miR-33 predisposes flies to elevated TAG levels, and we identified genes involved in TAG synthesis as direct targets of miR-33, including atpcl, midway, and Akt1. miR-33 mutants survived longer upon starvation but showed greater sensitivity to an oxidative stressor. We also found evidence that miR-33 is a negative regulator of cuticle pigmentation and that miR-33 mutants show a reduction in interfollicular stalk cells during oogenesis. CONCLUSION Our data suggest that miR-33 is a conserved regulator of lipid homeostasis, and its targets are involved in both degradation and synthesis of fatty acids and TAG. The constellation of phenotypes involving tissues that are highly sensitive to metabolic state suggests that miR-33 serves to prevent extreme fluctuations in metabolically sensitive tissues.
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Affiliation(s)
- Laure-Alix Clerbaux
- Laboratory of Physiological Chemistry, de Duve Institute, Université Catholique de Louvain, Bruxelles, Belgium.,Department of Biology and Program in Biochemistry, Vassar College, Poughkeepsie, New York, USA
| | - Hayley Schultz
- Department of Biology and Program in Biochemistry, Vassar College, Poughkeepsie, New York, USA
| | - Samara Roman-Holba
- Department of Biology and Program in Biochemistry, Vassar College, Poughkeepsie, New York, USA
| | - Dan Fu Ruan
- Department of Biology and Program in Biochemistry, Vassar College, Poughkeepsie, New York, USA
| | - Ronald Yu
- Department of Biology and Program in Biochemistry, Vassar College, Poughkeepsie, New York, USA
| | - Abigail M Lamb
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Guido T Bommer
- Laboratory of Physiological Chemistry, de Duve Institute, Université Catholique de Louvain, Bruxelles, Belgium
| | - Jennifer A Kennell
- Department of Biology and Program in Biochemistry, Vassar College, Poughkeepsie, New York, USA
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16
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Van De Bor V, Loreau V, Malbouyres M, Cerezo D, Placenti A, Ruggiero F, Noselli S. A dynamic and mosaic basement membrane controls cell intercalation in Drosophila ovaries. Development 2021; 148:dev.195511. [PMID: 33526583 DOI: 10.1242/dev.195511] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 01/13/2021] [Indexed: 12/18/2022]
Abstract
Basement membranes (BM) are extracellular matrices assembled into complex and highly organized networks essential for organ morphogenesis and function. However, little is known about the tissue origin of BM components and their dynamics in vivo Here, we unravel the assembly and role of the BM main component, Collagen type IV (ColIV), in Drosophila ovarian stalk morphogenesis. Stalks are short strings of cells assembled through cell intercalation that link adjacent follicles and maintain ovarian integrity. We show that stalk ColIV has multiple origins and is assembled following a regulated pattern leading to a unique BM organisation. Absence of ColIV leads to follicle fusion, as observed upon ablation of stalk cells. ColIV and integrins are both required to trigger cell intercalation and maintain mechanically strong cell-cell attachment within the stalk. These results show how the dynamic assembly of a mosaic BM controls complex tissue morphogenesis and integrity.
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Affiliation(s)
| | | | - Marilyne Malbouyres
- Institut de Génomique Fonctionnelle de Lyon, ENS de Lyon - CNRS UMR 5242 - INRA USC 1370, 46, allée d'Italie, 69364 Lyon cedex 07, France
| | | | | | - Florence Ruggiero
- Institut de Génomique Fonctionnelle de Lyon, ENS de Lyon - CNRS UMR 5242 - INRA USC 1370, 46, allée d'Italie, 69364 Lyon cedex 07, France
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17
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A Progressive Somatic Cell Niche Regulates Germline Cyst Differentiation in the Drosophila Ovary. Curr Biol 2021; 31:840-852.e5. [PMID: 33340458 DOI: 10.1016/j.cub.2020.11.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 10/02/2020] [Accepted: 11/18/2020] [Indexed: 12/20/2022]
Abstract
In the germarium of the Drosophila ovary, developing germline cysts are surrounded by a population of somatic escort cells that are known to function as the niche cells for germline differentiation;1 however, the underlying molecular mechanisms of this niche function remain poorly understood. Through single-cell gene expression profiling combined with genetic analyses, we here demonstrate that the escort cells can be spatially and functionally divided into two successive domains. The anterior escort cells (aECs) specifically produce ecdysone, which acts on the cystoblast to promote synchronous cell division, whereas the posterior escort cells (pECs) respond to ecdysone signaling and regulate soma-germline cell adhesion to promote the transition from 16-cell cyst-to-egg chamber formation. The patterning of the aEC and pEC domains is independent of the germline but is dependent on JAK/STAT signaling activity, which emanates from the posterior. Thus, a heterogeneous population of escort cells constitutes a stepwise niche environment to orchestrate cystoblast division and differentiation toward egg chamber formation.
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18
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A single-cell atlas and lineage analysis of the adult Drosophila ovary. Nat Commun 2020; 11:5628. [PMID: 33159074 PMCID: PMC7648648 DOI: 10.1038/s41467-020-19361-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/08/2020] [Indexed: 01/05/2023] Open
Abstract
The Drosophila ovary is a widely used model for germ cell and somatic tissue biology. Here we use single-cell RNA-sequencing (scRNA-seq) to build a comprehensive cell atlas of the adult Drosophila ovary that contains transcriptional profiles for every major cell type in the ovary, including the germline stem cells and their niche cells, follicle stem cells, and previously undescribed subpopulations of escort cells. In addition, we identify Gal4 lines with specific expression patterns and perform lineage tracing of subpopulations of escort cells and follicle cells. We discover that a distinct subpopulation of escort cells is able to convert to follicle stem cells in response to starvation or upon genetic manipulation, including knockdown of escargot, or overactivation of mTor or Toll signalling.
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19
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Jevitt A, Chatterjee D, Xie G, Wang XF, Otwell T, Huang YC, Deng WM. A single-cell atlas of adult Drosophila ovary identifies transcriptional programs and somatic cell lineage regulating oogenesis. PLoS Biol 2020; 18:e3000538. [PMID: 32339165 PMCID: PMC7205450 DOI: 10.1371/journal.pbio.3000538] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 05/07/2020] [Accepted: 03/27/2020] [Indexed: 12/28/2022] Open
Abstract
Oogenesis is a complex developmental process that involves spatiotemporally regulated coordination between the germline and supporting, somatic cell populations. This process has been modeled extensively using the Drosophila ovary. Although different ovarian cell types have been identified through traditional means, the large-scale expression profiles underlying each cell type remain unknown. Using single-cell RNA sequencing technology, we have built a transcriptomic data set for the adult Drosophila ovary and connected tissues. Using this data set, we identified the transcriptional trajectory of the entire follicle-cell population over the course of their development from stem cells to the oogenesis-to-ovulation transition. We further identify expression patterns during essential developmental events that take place in somatic and germline cell types such as differentiation, cell-cycle switching, migration, symmetry breaking, nurse-cell engulfment, egg-shell formation, and corpus luteum signaling. Extensive experimental validation of unique expression patterns in both ovarian and nearby, nonovarian cells also led to the identification of many new cell type-and stage-specific markers. The inclusion of several nearby tissue types in this data set also led to our identification of functional convergence in expression between distantly related cell types such as the immune-related genes that were similarly expressed in immune cells (hemocytes) and ovarian somatic cells (stretched cells) during their brief phagocytic role in nurse-cell engulfment. Taken together, these findings provide new insight into the temporal regulation of genes in a cell-type specific manner during oogenesis and begin to reveal the relatedness in expression between cell and tissues types.
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Affiliation(s)
- Allison Jevitt
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Deeptiman Chatterjee
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Gengqiang Xie
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Xian-Feng Wang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Taylor Otwell
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Yi-Chun Huang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Wu-Min Deng
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
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20
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Rust K, Nystul T. Signal transduction in the early Drosophila follicle stem cell lineage. CURRENT OPINION IN INSECT SCIENCE 2020; 37:39-48. [PMID: 32087562 PMCID: PMC7155752 DOI: 10.1016/j.cois.2019.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/13/2019] [Accepted: 11/16/2019] [Indexed: 05/08/2023]
Abstract
The follicle stem cell (FSC) lineage in the Drosophila ovary is a highly informative model of in vivo epithelial stem cell biology. Studies over the past 30 years have identified roles for every major signaling pathway in the early FSC lineage. These pathways regulate a wide variety of cell behaviors, including self-renewal, proliferation, survival and differentiation. Studies of cell signaling in the follicle epithelium have provided new insights into how these cell behaviors are coordinated within an epithelial stem cell lineage and how signaling pathways interact with each other in the native, in vivo context of a living tissue. Here, we review these studies, with a particular focus on how these pathways specify differences between the FSCs and their daughter cells. We also describe common themes that have emerged from these studies, and highlight new research directions that have been made possible by the detailed understanding of the follicle epithelium.
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21
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Fadiga J, Nystul TG. The follicle epithelium in the Drosophila ovary is maintained by a small number of stem cells. eLife 2019; 8:e49050. [PMID: 31850843 PMCID: PMC6946398 DOI: 10.7554/elife.49050] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/17/2019] [Indexed: 12/12/2022] Open
Abstract
The follicle stem cells (FSCs) in the Drosophila ovary are an important experimental model for the study of epithelial stem cell biology. Although decades of research support the conclusion that there are two FSCs per ovariole, a recent study used a novel clonal marking system to conclude that there are 15-16 FSCs per ovariole. We performed clonal analysis using both this novel clonal marking system and standard clonal marking systems, and identified several problems that may have contributed to the overestimate of FSC number. In addition, we developed new methods for accurately measuring clone size, and found that FSC clones produce, on average, half of the follicle cells in each ovariole. Our findings provide strong independent support for the conclusion that there are typically two active FSCs per ovariole, though they are consistent with up to four FSCs per germarium.
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Affiliation(s)
- Jocelyne Fadiga
- Department of AnatomyUniversity of California, San FranciscoSan FranciscoUnited States
- Department of OB/GYN-RS, Center for Reproductive SciencesUniversity of California, San FranciscoSan FranciscoUnited States
| | - Todd G Nystul
- Department of AnatomyUniversity of California, San FranciscoSan FranciscoUnited States
- Department of OB/GYN-RS, Center for Reproductive SciencesUniversity of California, San FranciscoSan FranciscoUnited States
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22
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Merkle JA, Wittes J, Schüpbach T. Signaling between somatic follicle cells and the germline patterns the egg and embryo of Drosophila. Curr Top Dev Biol 2019; 140:55-86. [PMID: 32591083 DOI: 10.1016/bs.ctdb.2019.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In Drosophila, specification of the embryonic body axes requires signaling between the germline and the somatic follicle cells. These signaling events are necessary to properly localize embryonic patterning determinants in the egg or eggshell during oogenesis. There are three maternal patterning systems that specify the anterior-posterior axis, and one that establishes the dorsal-ventral axis. We will first review oogenesis, focusing on the establishment of the oocyte and nurse cells and patterning of the follicle cells into different subpopulations. We then describe how two coordinated signaling events between the oocyte and follicle cells establish polarity of the oocyte and localize the anterior determinant bicoid, the posterior determinant oskar, and Gurken/epidermal growth factor (EGF), which breaks symmetry to initiate dorsal-ventral axis establishment. Next, we review how dorsal-ventral asymmetry of the follicle cells is transmitted to the embryo. This process also involves Gurken-EGF receptor (EGFR) signaling between the oocyte and follicle cells, leading to ventrally-restricted expression of the sulfotransferase Pipe. These events promote the ventral processing of Spaetzle, a ligand for Toll, which ultimately sets up the embryonic dorsal-ventral axis. We then describe the activation of the terminal patterning system by specialized polar follicle cells. Finally, we present open questions regarding soma-germline signaling during Drosophila oogenesis required for cell identity and embryonic axis formation.
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Affiliation(s)
- Julie A Merkle
- Department of Biology, University of Evansville, Evansville, IN, United States
| | - Julia Wittes
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Trudi Schüpbach
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States.
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23
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Kim-Yip RP, Nystul TG. Wingless promotes EGFR signaling in follicle stem cells to maintain self-renewal. Development 2018; 145:dev.168716. [PMID: 30389852 DOI: 10.1242/dev.168716] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/29/2018] [Indexed: 12/20/2022]
Abstract
Adult stem cell niche boundaries must be precisely maintained to facilitate the segregation of stem cell and daughter cell fates. However, the mechanisms that govern this process in epithelial tissues are not fully understood. In this study, we investigated the relationship between two signals, Wnt and EGFR, that are necessary for self-renewal of the epithelial follicle stem cells (FSCs) in the Drosophila ovary, but must be downregulated in cells that have exited the niche to allow for differentiation. We found that Wingless produced by inner germarial sheath (IGS) cells acts over a short distance to activate Wnt signaling in FSCs, and that movement across the FSC niche boundary is limited. In addition, we show that Wnt signaling functions genetically upstream of EGFR signaling by activating the expression of the EGFR ligand, Spitz, and that constitutive activation of EGFR partially rescues the self-renewal defect caused by loss of Wnt signaling. Collectively, our findings support a model in which the Wnt and EGFR pathways operate in a signaling hierarchy to promote FSC self-renewal.
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Affiliation(s)
- Rebecca P Kim-Yip
- Center for Reproductive Sciences, Departments of Anatomy and OB/GYN-RS, University of California, San Francisco, CA 94143-0452, USA
| | - Todd G Nystul
- Center for Reproductive Sciences, Departments of Anatomy and OB/GYN-RS, University of California, San Francisco, CA 94143-0452, USA
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24
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Kamath AD, Deehan MA, Frydman HM. Polar cell fate stimulates Wolbachia intracellular growth. Development 2018; 145:dev.158097. [PMID: 29467241 DOI: 10.1242/dev.158097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 02/12/2018] [Indexed: 11/20/2022]
Abstract
Bacteria are crucial partners in the development and evolution of vertebrates and invertebrates. A large fraction of insects harbor Wolbachia, bacterial endosymbionts that manipulate host reproduction to favor their spreading. Because they are maternally inherited, Wolbachia are under selective pressure to reach the female germline and infect the offspring. However, Wolbachia infection is not limited to the germline. Somatic cell types, including stem cell niches, have higher Wolbachia loads compared with the surrounding tissue. Here, we show a novel Wolbachia tropism to polar cells (PCs), specialized somatic cells in the Drosophila ovary. During oogenesis, all stages of PC development are easily visualized, facilitating the investigation of the kinetics of Wolbachia intracellular growth. Wolbachia accumulation is triggered by particular events of PC morphogenesis, including differentiation from progenitors and between stages 8 and 9 of oogenesis. Moreover, induction of ectopic PC fate is sufficient to promote Wolbachia accumulation. We found that Wolbachia PC tropism is evolutionarily conserved across most Drosophila species, but not in Culex mosquitos. These findings highlight the coordination of endosymbiont tropism with host development and cell differentiation.
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Affiliation(s)
- Ajit D Kamath
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Mark A Deehan
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Horacio M Frydman
- Department of Biology, Boston University, Boston, MA 02215, USA .,National Emerging Infectious Disease Laboratory, Boston University, Boston, MA 02118, USA
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25
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Borensztejn A, Mascaro A, Wharton KA. JAK/STAT signaling prevents excessive apoptosis to ensure maintenance of the interfollicular stalk critical for Drosophila oogenesis. Dev Biol 2018; 438:1-9. [PMID: 29571611 DOI: 10.1016/j.ydbio.2018.03.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/12/2018] [Accepted: 03/19/2018] [Indexed: 12/21/2022]
Abstract
Apoptosis not only eliminates cells that are damaged or dangerous but also cells whose function during development in patterning or organogenesis is complete. The successful formation of germ cells is essential for the perpetuation of a species. The production of an oocyte often depends on signaling between germline and somatic cells, but also between specialized types of somatic cells. In Drosophila, each developing egg chamber is separated from the next by a single file of interfollicular somatic cells. Little is known about the function of the interfollicular stalk, although its presumed role in separating egg chambers is to ensure that patterning cues from one egg chamber do not impact or disrupt the development of adjacent egg chambers. We found that cells comprising the stalk undergo a progressive decrease in number during oogenesis through an apoptotic-dependent loss. The extent of programmed cell death is restricted by JAK/STAT signaling in a cell-autonomous manner to ensure that the stalk is maintained. Both a failure to undergo the normal reduction in stalk cell number, or to prevent excessive stalk cell apoptosis results in a decrease in fecundity. Thus, activation of JAK/STAT signaling in the Drosophila interfollicular stalk emerges as a model to study the tight regulation of signaling-dependent apoptosis.
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Affiliation(s)
- Antoine Borensztejn
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Alexandra Mascaro
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Kristi A Wharton
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA.
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26
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Decreased expression of lethal giant larvae causes ovarian follicle cell outgrowth in the Drosophila Scutoid mutant. PLoS One 2017; 12:e0188917. [PMID: 29261681 PMCID: PMC5737974 DOI: 10.1371/journal.pone.0188917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/15/2017] [Indexed: 11/19/2022] Open
Abstract
Snail, a zinc-finger transcription factor, controls the process of epithelial-mesenchymal transition, and ectopic expression of this protein may produce cells with stem cell properties. Because the effect of Snail expression in ovarian epithelial cells remains unclear, we generated Drosophila ovarian follicle stem cells (FSCs) with homozygous Scutoid (Sco) mutation. The Sco mutation is a reciprocal transposition that is known to induce ectopic Snail activity. We found that Sco mutant FSCs showed excess proliferation and high competitiveness for niche occupancy, and the descendants of this lineage formed outgrowths that failed to enter the endocycle. Surprisingly, such phenotypes were not rescued by suppressing Snail expression, but were completely restored by supplying Lethal giant larvae (Lgl). The lgl allele is a cell polarity gene that is often mutated in the genome. Importantly, Sco mutants survived in a complementation test with lgl. This result was probably obtained because the Sco-associated lgl allele appears to diminish, but not ablate lgl expression. While our data do not rule out the possibility that the Sco mutation disrupts a regulator of lgl transcription, our results strongly suggest that the phenotypes we found in Sco mutants are more closely associated with the lgl allele than ectopic Snail activity.
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27
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Dai W, Peterson A, Kenney T, Burrous H, Montell DJ. Quantitative microscopy of the Drosophila ovary shows multiple niche signals specify progenitor cell fate. Nat Commun 2017; 8:1244. [PMID: 29093440 PMCID: PMC5665863 DOI: 10.1038/s41467-017-01322-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 09/09/2017] [Indexed: 01/28/2023] Open
Abstract
Adult stem cells commonly give rise to transit-amplifying progenitors, whose progeny differentiate into distinct cell types. It is unclear if stem cell niche signals coordinate fate decisions within the progenitor pool. Here we use quantitative analysis of Wnt, Hh, and Notch signalling reporters and the cell fate markers Eyes Absent (Eya) and Castor (Cas) to study the effects of hyper-activation and loss of niche signals on progenitor development in the Drosophila ovary. Follicle stem cell (FSC) progeny adopt distinct polar, stalk, and main body cell fates. We show that Wnt signalling transiently inhibits expression of the main body cell fate determinant Eya, and Wnt hyperactivity strongly biases cells towards polar and stalk fates. Hh signalling independently controls the proliferation to differentiation transition. Notch is permissive but not instructive for differentiation of multiple cell types. These findings reveal that multiple niche signals coordinate cell fates and differentiation of progenitor cells.
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Affiliation(s)
- Wei Dai
- MCDB Department, University of California, Santa Barbara, CA, 93106, USA
| | - Amy Peterson
- MCDB Department, University of California, Santa Barbara, CA, 93106, USA
| | - Thomas Kenney
- MCDB Department, University of California, Santa Barbara, CA, 93106, USA
| | - Haley Burrous
- MCDB Department, University of California, Santa Barbara, CA, 93106, USA
| | - Denise J Montell
- MCDB Department, University of California, Santa Barbara, CA, 93106, USA.
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28
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Yeh PA, Chang CJ. A novel function of twins, B subunit of protein phosphatase 2A, in regulating actin polymerization. PLoS One 2017; 12:e0186037. [PMID: 28977036 PMCID: PMC5627941 DOI: 10.1371/journal.pone.0186037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/22/2017] [Indexed: 11/18/2022] Open
Abstract
Actin is an important component of the cytoskeleton and its polymerization is delicately regulated by several kinases and phosphatases. Heterotrimeric protein phosphatase 2A (PP2A) is a potent phosphatase that is crucial for cell proliferation, apoptosis, tumorigenesis, signal transduction, cytoskeleton arrangement, and neurodegeneration. To facilitate these varied functions, different regulators determine the different targets of PP2A. Among these regulators of PP2A, the B subunits in particular may be involved in cytoskeleton arrangement. However, little is known about the role of PP2A in actin polymerization in vivo. Using sophisticated fly genetics, we demonstrated a novel function for the fly B subunit, twins, to promote actin polymerization in varied tissue types, suggesting a broad and conserved effect. Furthermore, our genetic data suggest that twins may act upstream of the actin-polymerized-proteins, Moesin and Myosin-light-chain, and downstream of Rho to promote actin polymerization. This work opens a new avenue for exploring the biological functions of a PP2A regulator, twins, in cytoskeleton regulation.
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Affiliation(s)
- Po-An Yeh
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan
- Department of Bioscience Technology, Chung Yuan Christian University, Chung Li, Taiwan
- * E-mail:
| | - Ching-Jin Chang
- Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei, Taiwan
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29
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The Hippo pathway acts downstream of the Hedgehog signaling to regulate follicle stem cell maintenance in the Drosophila ovary. Sci Rep 2017; 7:4480. [PMID: 28667262 PMCID: PMC5493701 DOI: 10.1038/s41598-017-04052-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 05/09/2017] [Indexed: 11/18/2022] Open
Abstract
The Hippo pathway is conserved and plays important roles in organ size control. The core components of the Hippo pathway are two kinases Hippo (Hpo), Warts (Wts), and a transcription-co-activator Yorkie (Yki). Yki activity is regulated by phosphorylation, which affects its nuclear localization and stability. To determine the role of the Hippo pathway in stem cells, we examine follicle stem cells (FSCs) in the Drosophila ovary. Yki is detected in the nucleus of FSCs. Knockdown of yki in the follicle cell lineage leads to a disruption of the follicular epithelium. Mitotic clones of FSCs mutant for hpo or wts are maintained in the niche and tend to replace the other FSCs, and FSCs mutant for yki are rapidly lost, demonstrating that the Hippo pathway is both required and sufficient for FSC maintenance. Using genetic interaction analyses, we demonstrate that the Hedgehog pathway acts upstream of the Hippo pathway in regulating FSC maintenance. The nuclear localization of Yki is enhanced when the Hedgehog signaling is activated. Furthermore, a constitutively active but not a wild-type Yki promotes FSC maintenance as activation of the Hedgehog signaling does, suggesting that the Hedgehog pathway regulates Yki through a post-translational mechanism in maintaining FSCs.
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30
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Teuscher M, Ströhlein N, Birkenbach M, Schultheis D, Schoppmeier M. TC003132 is essential for the follicle stem cell lineage in telotrophic Tribolium oogenesis. Front Zool 2017; 14:26. [PMID: 28533810 PMCID: PMC5438533 DOI: 10.1186/s12983-017-0212-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/11/2017] [Indexed: 12/31/2022] Open
Abstract
Background Stem cells are undifferentiated cells with a potential for self-renewal, which are essential to support normal development and homeostasis. To gain insight into the molecular mechanisms underlying adult stem cell biology and organ evolution, we use the telotrophic ovary of the beetle Tribolium. To this end, we participated in a large-scale RNAi screen in the red flour beetle Tribolium, which identified functions in embryonic and postembryonic development for more than half of the Tribolium genes. Results We identified TC003132 as candidate gene for the follicle stem cell linage in telotrophic Tribolium oogenesis. TC003132 belongs to the Casein Kinase 2 substrate family (CK2S), which in humans is associated with the proliferative activity of different cancers. Upon TC003132 RNAi, central pre-follicular cells are lost, which results in termination of oogenesis. Given that also Notch-signalling is required to promote the mitotic activity of central pre-follicular cells, we performed epistasis experiments with Notch and cut. In addition, we identified a putative follicle stem cell population by monitoring the mitotic pattern of wild type and TC003132 depleted follicle cells by EdU incorporations. In TC003132 RNAi these putative FSCs cease the expression of differentiation makers and are eventually lost. Conclusions TC003132 depleted pre-follicular cells neither react to mitosis or endocycle stimulating signals, suggesting that TC003132 provides competence for differentiation cues. This may resemble the situation in C. elegans were CK2 is required to maintain the balance between proliferation and differentiation in the germ line. Since the earliest effect of TC003132 RNAi is characterized by the loss of putative FSCs, we posit that TC003132 crucially contributes to the proliferation or maintenance of follicle stem cells in the telotrophic Tribolium ovary. Electronic supplementary material The online version of this article (doi:10.1186/s12983-017-0212-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthias Teuscher
- Department Biology, Developmental Biology Unit, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Nadi Ströhlein
- Department Biology, Developmental Biology Unit, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Markus Birkenbach
- Department Biology, Developmental Biology Unit, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Dorothea Schultheis
- Present address: Institute of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany
| | - Michael Schoppmeier
- Department Biology, Developmental Biology Unit, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
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Duhart JC, Parsons TT, Raftery LA. The repertoire of epithelial morphogenesis on display: Progressive elaboration of Drosophila egg structure. Mech Dev 2017; 148:18-39. [PMID: 28433748 DOI: 10.1016/j.mod.2017.04.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/07/2017] [Accepted: 04/12/2017] [Indexed: 12/26/2022]
Abstract
Epithelial structures are foundational for tissue organization in all metazoans. Sheets of epithelial cells form lateral adhesive junctions and acquire apico-basal polarity perpendicular to the surface of the sheet. Genetic analyses in the insect model, Drosophila melanogaster, have greatly advanced our understanding of how epithelial organization is established, and how it is modulated during tissue morphogenesis. Major insights into collective cell migrations have come from analyses of morphogenetic movements within the adult follicular epithelium that cooperates with female germ cells to build a mature egg. Epithelial follicle cells progress through tightly choreographed phases of proliferation, patterning, reorganization and migrations, before they differentiate to form the elaborate structures of the eggshell. Distinct structural domains are organized by differential adhesion, within which lateral junctions are remodeled to further shape the organized epithelia. During collective cell migrations, adhesive interactions mediate supracellular organization of planar polarized macromolecules, and facilitate crawling over the basement membrane or traction against adjacent cell surfaces. Comparative studies with other insects are revealing the diversification of morphogenetic movements for elaboration of epithelial structures. This review surveys the repertoire of follicle cell morphogenesis, to highlight the coordination of epithelial plasticity with progressive differentiation of a secretory epithelium. Technological advances will keep this tissue at the leading edge for interrogating the precise spatiotemporal regulation of normal epithelial reorganization events, and provide a framework for understanding pathological tissue dysplasia.
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Affiliation(s)
- Juan Carlos Duhart
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, United States
| | - Travis T Parsons
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, United States
| | - Laurel A Raftery
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, United States.
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Reilein A, Melamed D, Park KS, Berg A, Cimetta E, Tandon N, Vunjak-Novakovic G, Finkelstein S, Kalderon D. Alternative direct stem cell derivatives defined by stem cell location and graded Wnt signalling. Nat Cell Biol 2017; 19:433-444. [PMID: 28414313 PMCID: PMC5672635 DOI: 10.1038/ncb3505] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 03/06/2017] [Indexed: 12/15/2022]
Abstract
Adult stem cells provide a renewable source of differentiated cells for a wide variety of tissues and generally give rise to multiple cell types. Basic principles of stem cell organization and regulation underlying this behavior are emerging. Local niche signals maintain stem cells, while different sets of signals act outside the niche to diversify initially equivalent stem cell progeny. Here we show that Drosophila ovarian Follicle Stem Cells (FSCs) produced two distinct cell types directly. This cell fate choice was determined by the A/P position of an FSC and by the magnitude of spatially graded Wnt pathway activity. These findings reveal a paradigm of immediate diversification of stem cell derivatives according to stem cell position within a larger population, guided by a graded niche signal. We also found that FSCs strongly resemble mammalian intestinal stem cells in many aspects of their organization, including population asymmetry and dynamic heterogeneity.
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Affiliation(s)
- Amy Reilein
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - David Melamed
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Karen Sophia Park
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Ari Berg
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Elisa Cimetta
- Department of Biomedical Engineering, Columbia University, New York, New York 10032, USA
| | - Nina Tandon
- Department of Biomedical Engineering, Columbia University, New York, New York 10032, USA
| | | | - Sarah Finkelstein
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Daniel Kalderon
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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33
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Hirono K, Kohwi M, Clark MQ, Heckscher ES, Doe CQ. The Hunchback temporal transcription factor establishes, but is not required to maintain, early-born neuronal identity. Neural Dev 2017; 12:1. [PMID: 28137283 PMCID: PMC5282720 DOI: 10.1186/s13064-017-0078-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/26/2017] [Indexed: 01/01/2023] Open
Abstract
Background Drosophila and mammalian neural progenitors typically generate a diverse family of neurons in a stereotyped order. Neuronal diversity can be generated by the sequential expression of temporal transcription factors. In Drosophila, neural progenitors (neuroblasts) sequentially express the temporal transcription factors Hunchback (Hb), Kruppel, Pdm, and Castor. Hb is necessary and sufficient to specify early-born neuronal identity in multiple lineages, and is maintained in the post-mitotic neurons produced during each neuroblast expression window. Surprisingly, nothing is currently known about whether Hb acts in neuroblasts or post-mitotic neurons (or both) to specify first-born neuronal identity. Methods Here we selectively remove Hb from post-mitotic neurons, and assay the well-characterized NB7-1 and NB1-1 lineages for defects in neuronal identity and function. Results We find that loss of Hb from embryonic and larval post-mitotic neurons does not affect neuronal identity. Furthermore, removing Hb from post-mitotic neurons throughout the entire CNS has no effect on larval locomotor velocity, a sensitive assay for motor neuron and pre-motor neuron function. Conclusions We conclude that Hb functions in progenitors (neuroblasts/GMCs) to establish heritable neuronal identity that is maintained by a Hb-independent mechanism. We suggest that Hb acts in neuroblasts to establish an epigenetic state that is permanently maintained in early-born neurons. Electronic supplementary material The online version of this article (doi:10.1186/s13064-017-0078-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Keiko Hirono
- Howard Hughes Medical Institute, Eugene, 97403, USA.,Institute of Molecular Biology, Eugene, 97403, USA.,Institute of Neuroscience, University of Oregon, Eugene, 97403, USA
| | - Minoree Kohwi
- Department of Neuroscience, Columbia University Medical Center, New York, NY, 10032, USA
| | - Matt Q Clark
- Howard Hughes Medical Institute, Eugene, 97403, USA.,Institute of Molecular Biology, Eugene, 97403, USA.,Institute of Neuroscience, University of Oregon, Eugene, 97403, USA
| | - Ellie S Heckscher
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Chris Q Doe
- Howard Hughes Medical Institute, Eugene, 97403, USA. .,Institute of Molecular Biology, Eugene, 97403, USA. .,Institute of Neuroscience, University of Oregon, Eugene, 97403, USA.
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Flora P, McCarthy A, Upadhyay M, Rangan P. Role of Chromatin Modifications in Drosophila Germline Stem Cell Differentiation. Results Probl Cell Differ 2017; 59:1-30. [PMID: 28247044 DOI: 10.1007/978-3-319-44820-6_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
During Drosophila oogenesis, germline stem cells (GSCs) self-renew and differentiate to give rise to a mature egg. Self-renewal and differentiation of GSCs are regulated by both intrinsic mechanisms such as regulation of gene expression in the germ line and extrinsic signaling pathways from the surrounding somatic niche. Epigenetic mechanisms, including histone-modifying proteins, nucleosome remodeling complexes, and histone variants, play a critical role in regulating intrinsic gene expression and extrinsic signaling cues from the somatic niche. In the GSCs, intrinsic epigenetic modifiers are required to maintain a stem cell fate by promoting expression of self-renewal factors and repressing the differentiation program. Subsequently, in the GSC daughters, epigenetic regulators activate the differentiation program to promote GSC differentiation. During differentiation, the GSC daughter undergoes meiosis to give rise to the developing egg, containing a compacted chromatin architecture called the karyosome. Epigenetic modifiers control the attachment of chromosomes to the nuclear lamina to aid in meiotic recombination and the release from the lamina for karyosome formation. The germ line is in close contact with the soma for the entirety of this developmental process. This proximity facilitates signaling from the somatic niche to the developing germ line. Epigenetic modifiers play a critical role in the somatic niche, modulating signaling pathways in order to coordinate the transition of GSC to an egg. Together, intrinsic and extrinsic epigenetic mechanisms modulate this exquisitely balanced program.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Alicia McCarthy
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Maitreyi Upadhyay
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA.
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.
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Riechmann V. In vivo RNAi in the Drosophila Follicular Epithelium: Analysis of Stem Cell Maintenance, Proliferation, and Differentiation. Methods Mol Biol 2017; 1622:185-206. [PMID: 28674810 DOI: 10.1007/978-1-4939-7108-4_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In vivo RNAi in Drosophila facilitates simple and rapid analysis of gene functions in a cell- or tissue-specific manner. The versatility of the UAS-GAL4 system allows to control exactly where and when during development the function of a gene is depleted. The epithelium of the ovary is a particularly good model to study in a living animal how stem cells are maintained and how their descendants proliferate and differentiate. Here I provide basic information about the publicly available reagents for in vivo RNAi, and I describe how the oogenesis system can be applied to analyze stem cells and epithelial development at a histological level. Moreover, I give helpful hints to optimize the use of the UAS-GAL4 system for RNAi induction in the follicular epithelium. Finally, I provide detailed step-by-step protocols for ovary dissection, antibody stainings, and ovary mounting for microscopic analysis.
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Affiliation(s)
- Veit Riechmann
- Medical Faculty Mannheim, Department of Cell and Molecular Biology, Heidelberg University, Ludolf-Krehl-Strasse 13-17, D-68167, Mannheim, Germany.
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36
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Johnston MJ, Bar-Cohen S, Paroush Z, Nystul TG. Phosphorylated Groucho delays differentiation in the follicle stem cell lineage by providing a molecular memory of EGFR signaling in the niche. Development 2016; 143:4631-4642. [PMID: 27836963 PMCID: PMC5201033 DOI: 10.1242/dev.143263] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/31/2016] [Indexed: 01/03/2023]
Abstract
In the epithelial follicle stem cells (FSCs) of the Drosophila ovary, Epidermal Growth Factor Receptor (EGFR) signaling promotes self-renewal, whereas Notch signaling promotes differentiation of the prefollicle cell (pFC) daughters. We have identified two proteins, Six4 and Groucho (Gro), that link the activity of these two pathways to regulate the earliest cell fate decision in the FSC lineage. Our data indicate that Six4 and Gro promote differentiation towards the polar cell fate by promoting Notch pathway activity. This activity of Gro is antagonized by EGFR signaling, which inhibits Gro-dependent repression via p-ERK mediated phosphorylation. We have found that the phosphorylated form of Gro persists in newly formed pFCs, which may delay differentiation and provide these cells with a temporary memory of the EGFR signal. Collectively, these findings demonstrate that phosphorylated Gro labels a transition state in the FSC lineage and describe the interplay between Notch and EGFR signaling that governs the differentiation processes during this period.
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Affiliation(s)
- Michael J Johnston
- The University of California, San Francisco, Departments of Anatomy and OB-GYN/RS, CA 94122, USA
| | - Shaked Bar-Cohen
- The Hebrew University, Department of Developmental Biology and Cancer Research, IMRIC, Faculty of Medicine, Jerusalem 9112102, Israel
| | - Ze'ev Paroush
- The Hebrew University, Department of Developmental Biology and Cancer Research, IMRIC, Faculty of Medicine, Jerusalem 9112102, Israel
| | - Todd G Nystul
- The University of California, San Francisco, Departments of Anatomy and OB-GYN/RS, CA 94122, USA
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37
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Ulmschneider B, Grillo-Hill BK, Benitez M, Azimova DR, Barber DL, Nystul TG. Increased intracellular pH is necessary for adult epithelial and embryonic stem cell differentiation. J Cell Biol 2016; 215:345-355. [PMID: 27821494 PMCID: PMC5100294 DOI: 10.1083/jcb.201606042] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/18/2016] [Accepted: 10/05/2016] [Indexed: 12/19/2022] Open
Abstract
Despite extensive knowledge about the transcriptional regulation of stem cell differentiation, less is known about the role of dynamic cytosolic cues. We report that an increase in intracellular pH (pHi) is necessary for the efficient differentiation of Drosophila adult follicle stem cells (FSCs) and mouse embryonic stem cells (mESCs). We show that pHi increases with differentiation from FSCs to prefollicle cells (pFCs) and follicle cells. Loss of the Drosophila Na+-H+ exchanger DNhe2 lowers pHi in differentiating cells, impairs pFC differentiation, disrupts germarium morphology, and decreases fecundity. In contrast, increasing pHi promotes excess pFC cell differentiation toward a polar/stalk cell fate through suppressing Hedgehog pathway activity. Increased pHi also occurs with mESC differentiation and, when prevented, attenuates spontaneous differentiation of naive cells, as determined by expression of microRNA clusters and stage-specific markers. Our findings reveal a previously unrecognized role of pHi dynamics for the differentiation of two distinct types of stem cell lineages, which opens new directions for understanding conserved regulatory mechanisms.
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Affiliation(s)
- Bryne Ulmschneider
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143
| | - Bree K Grillo-Hill
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
- Department of Biological Sciences, San Jose State University, San Jose, CA 95192
| | - Marimar Benitez
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143
| | - Dinara R Azimova
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
| | - Todd G Nystul
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143
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38
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Laws KM, Drummond-Barbosa D. AMP-activated protein kinase has diet-dependent and -independent roles in Drosophila oogenesis. Dev Biol 2016; 420:90-99. [PMID: 27729213 DOI: 10.1016/j.ydbio.2016.10.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/16/2016] [Accepted: 10/07/2016] [Indexed: 12/31/2022]
Abstract
Multiple aspects of organismal physiology influence the number and activity of stem cells and their progeny, including nutritional status. Previous studies demonstrated that Drosophila germline stem cells (GSCs), follicle stem cells (FSCs), and their progeny sense and respond to diet via complex mechanisms involving many systemic and local signals. AMP-activated protein kinase, or AMPK, is a highly conserved regulator of energy homeostasis known to be activated under low cellular energy conditions; however, its role in the ovarian response to diet has not been investigated. Here, we describe nutrient-dependent and -independent requirements for AMPK in Drosophila oogenesis. We found that AMPK is cell autonomously required for the slow down in GSC and follicle cell proliferation that occurs on a poor diet. Similarly, AMPK activity is necessary in the germline for the degeneration of vitellogenic stages in response to nutrient deprivation. In contrast, AMPK activity is not required within the germline to modulate its growth. Instead, AMPK acts in follicle cells to negatively regulate their growth and proliferation, thereby indirectly limiting the size of the underlying germline cyst within developing follicles. Paradoxically, AMPK is required for GSC maintenance in well-fed flies (when AMPK activity is presumably at its lowest), suggesting potentially important roles for basal AMPK activity in specific cell types. Finally, we identified a nutrient-independent, developmental role for AMPK in cyst encapsulation by follicle cells. These results uncover specific AMPK requirements in multiple cell types in the ovary and suggest that AMPK can function outside of its canonical nutrient-sensing role in specific developmental contexts.
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Affiliation(s)
- Kaitlin M Laws
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W3118, Baltimore, MD 21205, USA.
| | - Daniela Drummond-Barbosa
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W3118, Baltimore, MD 21205, USA; Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W3118, Baltimore, MD 21205, USA.
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A Genetic Mosaic Screen Reveals Ecdysone-Responsive Genes Regulating Drosophila Oogenesis. G3-GENES GENOMES GENETICS 2016; 6:2629-42. [PMID: 27226164 PMCID: PMC4978916 DOI: 10.1534/g3.116.028951] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Multiple aspects of Drosophila oogenesis, including germline stem cell activity, germ cell differentiation, and follicle survival, are regulated by the steroid hormone ecdysone. While the transcriptional targets of ecdysone signaling during development have been studied extensively, targets in the ovary remain largely unknown. Early studies of salivary gland polytene chromosomes led to a model in which ecdysone stimulates a hierarchical transcriptional cascade, wherein a core group of ecdysone-sensitive transcription factors induce tissue-specific responses by activating secondary branches of transcriptional targets. More recently, genome-wide approaches have identified hundreds of putative ecdysone-responsive targets. Determining whether these putative targets represent bona fide targets in vivo, however, requires that they be tested via traditional mutant analysis in a cell-type specific fashion. To investigate the molecular mechanisms whereby ecdysone signaling regulates oogenesis, we used genetic mosaic analysis to screen putative ecdysone-responsive genes for novel roles in the control of the earliest steps of oogenesis. We identified a cohort of genes required for stem cell maintenance, stem and progenitor cell proliferation, and follicle encapsulation, growth, and survival. These genes encode transcription factors, chromatin modulators, and factors required for RNA transport, stability, and ribosome biogenesis, suggesting that ecdysone might control a wide range of molecular processes during oogenesis. Our results suggest that, although ecdysone target genes are known to have cell type-specific roles, many ecdysone response genes that control larval or pupal cell types at developmental transitions are used reiteratively in the adult ovary. These results provide novel insights into the molecular mechanisms by which ecdysone signaling controls oogenesis, laying new ground for future studies.
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Tseng CY, Kao SH, Hsu HJ. Snail controls proliferation of Drosophila ovarian epithelial follicle stem cells, independently of E-cadherin. Dev Biol 2016; 414:142-8. [DOI: 10.1016/j.ydbio.2016.04.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/28/2016] [Accepted: 04/28/2016] [Indexed: 01/11/2023]
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Hedgehog Signaling Strength Is Orchestrated by the mir-310 Cluster of MicroRNAs in Response to Diet. Genetics 2016; 202:1167-83. [PMID: 26801178 PMCID: PMC4788116 DOI: 10.1534/genetics.115.185371] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/18/2016] [Indexed: 01/08/2023] Open
Abstract
Since the discovery of microRNAs (miRNAs) only two decades ago, they have emerged as an essential component of the gene regulatory machinery. miRNAs have seemingly paradoxical features: a single miRNA is able to simultaneously target hundreds of genes, while its presence is mostly dispensable for animal viability under normal conditions. It is known that miRNAs act as stress response factors; however, it remains challenging to determine their relevant targets and the conditions under which they function. To address this challenge, we propose a new workflow for miRNA function analysis, by which we found that the evolutionarily young miRNA family, the mir-310s (mir-310/mir-311/mir-312/mir-313), are important regulators of Drosophila metabolic status. mir-310s-deficient animals have an abnormal diet-dependent expression profile for numerous diet-sensitive components, accumulate fats, and show various physiological defects. We found that the mir-310s simultaneously repress the production of several regulatory factors (Rab23, DHR96, and Ttk) of the evolutionarily conserved Hedgehog (Hh) pathway to sharpen dietary response. As the mir-310s expression is highly dynamic and nutrition sensitive, this signal relay model helps to explain the molecular mechanism governing quick and robust Hh signaling responses to nutritional changes. Additionally, we discovered a new component of the Hh signaling pathway in Drosophila, Rab23, which cell autonomously regulates Hh ligand trafficking in the germline stem cell niche. How organisms adjust to dietary fluctuations to sustain healthy homeostasis is an intriguing research topic. These data are the first to report that miRNAs can act as executives that transduce nutritional signals to an essential signaling pathway. This suggests miRNAs as plausible therapeutic agents that can be used in combination with low calorie and cholesterol diets to manage quick and precise tissue-specific responses to nutritional changes.
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Abstract
Drosophila oogenesis is a powerful model for studying a wide spectrum of cellular and developmental processes in vivo. Oogenesis starts in a specialized structure called the germarium, which harbors the stem cells for both germ and somatic cells. The germarium produces egg chambers, each of which will develop into an egg. Active areas of research in Drosophila germaria include stem cell self-renewal, division, and maintenance, cell cycle control and differentiation, oocyte specification, intercellular communication, and signaling, among others. The solid knowledge base, the genetic tractability of the Drosophila model, as well as the availability and fast development of tools and imaging techniques for oogenesis research ensure that studies in this model will keep being instrumental for novel discoveries within cell and developmental biology also in the future. This chapter focuses on antibody staining in Drosophila germaria and provides a protocol for immunostaining as well as an overview of commonly used antibodies for visualization of different cell types and cellular structures. The protocol is well-suited for subsequent confocal microscopy analyses, and in addition we present key adaptations of the protocol that are useful when performing structured illumination microscopy (SIM) super-resolution imaging.
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Affiliation(s)
- Anette Lie-Jensen
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, N-0379, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway
| | - Kaisa Haglund
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, N-0379, Oslo, Norway.
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway.
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Discs large 5, an Essential Gene in Drosophila, Regulates Egg Chamber Organization. G3-GENES GENOMES GENETICS 2015; 5:943-52. [PMID: 25795662 PMCID: PMC4426378 DOI: 10.1534/g3.115.017558] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Discs large 5 (Dlg5) is a member of the MAGUK family of proteins that typically serve as molecular scaffolds and mediate signaling complex formation and localization. In vertebrates, Dlg5 has been shown to be responsible for polarization of neural progenitors and to associate with Rab11-positive vesicles in epithelial cells. In Drosophila, however, the function of Dlg5 is not well-documented. We have identified dlg5 as an essential gene that shows embryonic lethality. dlg5 embryos display partial loss of primordial germ cells (PGCs) during gonad coalescence between stages 12 and 15 of embryogenesis. Loss of Dlg5 in germline and somatic stem cells in the ovary results in the depletion of both cell lineages. Reduced expression of Dlg5 in the follicle cells of the ovary leads to a number of distinct phenotypes, including defects in egg chamber budding, stalk cell overgrowth, and ectopic polar cell induction. Interestingly, loss of Dlg5 in follicle cells results in abnormal distribution of a critical component of cell adhesion, E-cadherin, shown to be essential for proper organization of egg chambers.
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Vlachos S, Jangam S, Conder R, Chou M, Nystul T, Harden N. A Pak-regulated cell intercalation event leading to a novel radial cell polarity is involved in positioning of the follicle stem cell niche in the Drosophila ovary. Development 2015; 142:82-91. [PMID: 25516970 DOI: 10.1242/dev.111039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the germarium of the Drosophila ovary, germline cysts are encapsulated one at a time by a follicular epithelium derived from two follicle stem cells (FSCs). Ovaries in flies mutant for the serine/threonine kinase Pak exhibit a novel phenotype, in which two side-by-side cysts are encapsulated at a time, generating paired egg chambers. This striking phenotype originates in the pupal ovary, where the developing germarium is shaped by the basal stalk, a stack of cells formed by cell intercalation. The process of basal stalk formation is not well understood, and we provide evidence that the cell intercalation is driven by actomyosin contractility of DE-Cadherin-adhered cells, leading to a column of disk-shaped cells exhibiting a novel radial cell polarity. Cell intercalation fails in Pak mutant ovaries, leading to abnormally wide basal stalks and consequently wide germaria with side-by-side cysts. We present evidence that Pak mutant germaria have extra FSCs, and we propose that contact of a germline cyst with the basal stalk in the pupal ovary contributes to FSC niche formation. The wide basal stalk in Pak mutants enables the formation of extra FSC niches which are mispositioned and yet functional, indicating that the FSC niche can be established in diverse locations.
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Affiliation(s)
- Stephanie Vlachos
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Sharayu Jangam
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Ryan Conder
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Michael Chou
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Todd Nystul
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6 Departments of Anatomy and OB/GYN-RS, University of California, San Francisco, CA 94143, USA
| | - Nicholas Harden
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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The Jak-STAT target Chinmo prevents sex transformation of adult stem cells in the Drosophila testis niche. Dev Cell 2014; 31:474-86. [PMID: 25453558 DOI: 10.1016/j.devcel.2014.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 08/29/2014] [Accepted: 10/03/2014] [Indexed: 12/22/2022]
Abstract
Local signals maintain adult stem cells in many tissues. Whether the sexual identity of adult stem cells must also be maintained was not known. In the adult Drosophila testis niche, local Jak-STAT signaling promotes somatic cyst stem cell (CySC) renewal through several effectors, including the putative transcription factor Chronologically inappropriate morphogenesis (Chinmo). Here, we find that Chinmo also prevents feminization of CySCs. Chinmo promotes expression of the canonical male sex determination factor DoublesexM (Dsx(M)) within CySCs and their progeny, and ectopic expression of DsxM in the CySC lineage partially rescues the chinmo sex transformation phenotype, placing Chinmo upstream of Dsx(M). The Dsx homolog DMRT1 prevents the male-to-female conversion of differentiated somatic cells in the adult mammalian testis, but its regulation is not well understood. Our work indicates that sex maintenance occurs in adult somatic stem cells and that this highly conserved process is governed by effectors of niche signals. PAPERCLIP:
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Abstract
The Drosophila melanogaster genetic tool box includes many stocks for generating genetically mosaic tissue in which a clone of cells, related by lineage, contain a common genetic alteration. These tools have made it possible to study the postembryonic function of essential genes and to better understand how individual cells interact within intact tissues. We have screened through 201 enhancer-trap flippase lines to identify lines that produce useful clone patterns in the adult ovary. We found that approximately 70% of the lines produced clones that were present in the adult ovary and that many ovarian cell types were represented among the different clone patterns produced by these lines. We have also identified and further characterized five particularly useful enhancer-trap flippase lines. These lines make it possible to generate clones specifically in germ cells, escort cells, prefollicle cells, or terminal filament cells. In addition, we have found that chickadee is specifically upregulated in the posterior escort cells, follicle stem cells, and prefollicle cells that comprise the follicle stem cell niche region. Collectively, these studies provide several new tools for genetic mosaic analysis in the Drosophila ovary.
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Kronen MR, Schoenfelder KP, Klein AM, Nystul TG. Basolateral junction proteins regulate competition for the follicle stem cell niche in the Drosophila ovary. PLoS One 2014; 9:e101085. [PMID: 24991805 PMCID: PMC4084627 DOI: 10.1371/journal.pone.0101085] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/02/2014] [Indexed: 11/26/2022] Open
Abstract
Epithelial stem cells are routinely lost or damaged during adult life and must therefore be replaced to maintain homeostasis. Recent studies indicate that stem cell replacement occurs through neutral competition in many types of epithelial tissues, but little is known about the factors that determine competitive outcome. The epithelial follicle stem cells (FSCs) in the Drosophila ovary are regularly lost and replaced during normal homeostasis, and we show that FSC replacement conforms to a model of neutral competition. In addition, we found that FSCs mutant for the basolateral junction genes, lethal giant larvae (lgl) or discs large (dlg), undergo a biased competition for niche occupancy characterized by increased invasion of neighboring FSCs and reduced loss. Interestingly, FSCs mutant for a third basolateral junction gene, scribble (scrib), do not exhibit biased competition, suggesting that Lgl and Dlg regulate niche competition through a Scrib-independent process. Lastly, we found that FSCs have a unique cell polarity characterized by broadly distributed adherens junctions and the lack of a mature apical domain. Collectively, these observations indicate that Lgl and Dlg promote the differentiation of FSC progeny to a state in which they are less prone to invade the neighboring niche. In addition, we demonstrate that the neutral drift model can be adapted to quantify non-neutral behavior of mutant clones.
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Affiliation(s)
- Maria R. Kronen
- University of California, San Francisco, Center for Reproductive Sciences, Departments of Anatomy and OB/GYN-RS, San Francisco, California, United States of America
| | - Kevin P. Schoenfelder
- University of California, San Francisco, Center for Reproductive Sciences, Departments of Anatomy and OB/GYN-RS, San Francisco, California, United States of America
| | - Allon M. Klein
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (TGN); (AMK)
| | - Todd G. Nystul
- University of California, San Francisco, Center for Reproductive Sciences, Departments of Anatomy and OB/GYN-RS, San Francisco, California, United States of America
- * E-mail: (TGN); (AMK)
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Amin NM, Gibbs D, Conlon FL. Differential regulation of CASZ1 protein expression during cardiac and skeletal muscle development. Dev Dyn 2014; 243:948-56. [PMID: 24633745 DOI: 10.1002/dvdy.24126] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 02/19/2014] [Accepted: 02/27/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The zinc-finger transcription factor CASZ1 is required for differentiation of a distinct population of cardiomyocytes during development. However, expression of Casz1 mRNA is detected throughout the developing heart, suggesting the spatial regulation of CASZ1 occurs at the protein level. Relatively little is known about posttranscriptional regulation of Casz1 in the heart. RESULTS We generated antibodies that specifically recognize CASZ1 in developing Xenopus embryos, and performed immunofluorescence analysis of CASZ1 during cardiac development. CASZ1 was detected throughout the developing myocardium. CASZ1 was restricted to terminally differentiated cardiomyocytes, and was down-regulated in cells that re-enter the cell cycle. We determined that CASZ1 expression correlated with terminal differentiation in cardiac muscle cells, skeletal muscle cells, and lymph-heart musculature. CONCLUSIONS This study indicates that spatially distinct expression of CASZ1 protein may be due to posttranscriptional control of Casz1 mRNA during cardiac development. The results of this study provide insights into the role of Casz1 in cardiac function and in the differentiation of other cell types, including skeletal muscle and lymph heart.
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Affiliation(s)
- Nirav M Amin
- University of North Carolina McAllister Heart Institute, UNC-Chapel Hill, Chapel Hill, North Carolina; Department of Genetics, UNC-Chapel Hill, Chapel Hill, North Carolina
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Berns N, Woichansky I, Friedrichsen S, Kraft N, Riechmann V. A genome-scale in vivo RNAi analysis of epithelial development in Drosophila identifies new proliferation domains outside of the stem cell niche. J Cell Sci 2014; 127:2736-48. [PMID: 24762813 DOI: 10.1242/jcs.144519] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Drosophila oogenesis system provides an excellent model to study the development of epithelial tissues. Here, we report the first genome-scale in vivo RNA interference (RNAi) screen for genes controlling epithelial development. By directly analysing cell and tissue architecture we identified 1125 genes, which we assigned to seven different functions in epithelial formation and homeostasis. We validated the significance of our screen by generating mutants for Vps60, a component of the endosomal sorting complexes required for transport (ESCRT) machinery. This analysis provided new insights into spatiotemporal control of cell proliferation in the follicular epithelium. Previous studies have identified signals controlling divisions in the follicle stem cell niche. However, 99% of cell divisions occur outside of the niche and it is unclear how these divisions are controlled. Our data distinguish two new domains outside of the stem cell niche where there are differing controls on proliferation. One domain abuts the niche and is characterised by ESCRT, Notch and JAK/STAT-mediated control of proliferation. Adjacent to this domain, another domain is defined by loss of the impact of ESCRT on cell division. Thus, during development epithelial cells pass through a variety of microenvironments that exert different modes of proliferation control. The switch between these modes might reflect a decrease in the 'stemness' of epithelial cells over time.
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Affiliation(s)
- Nicola Berns
- Heidelberg University, Medical Faculty Mannheim, Department of Cell and Molecular Biology and German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Innokenty Woichansky
- Heidelberg University, Medical Faculty Mannheim, Department of Cell and Molecular Biology and German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Steffen Friedrichsen
- Heidelberg University, Medical Faculty Mannheim, Department of Cell and Molecular Biology and German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Nadine Kraft
- Heidelberg University, Medical Faculty Mannheim, Department of Cell and Molecular Biology and German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Veit Riechmann
- Heidelberg University, Medical Faculty Mannheim, Department of Cell and Molecular Biology and German Cancer Research Center (DKFZ), Division of Signaling and Functional Genomics, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
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Hammonds AS, Bristow CA, Fisher WW, Weiszmann R, Wu S, Hartenstein V, Kellis M, Yu B, Frise E, Celniker SE. Spatial expression of transcription factors in Drosophila embryonic organ development. Genome Biol 2013; 14:R140. [PMID: 24359758 PMCID: PMC4053779 DOI: 10.1186/gb-2013-14-12-r140] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 12/20/2013] [Indexed: 11/29/2022] Open
Abstract
Background Site-specific transcription factors (TFs) bind DNA regulatory elements to control expression of target genes, forming the core of gene regulatory networks. Despite decades of research, most studies focus on only a small number of TFs and the roles of many remain unknown. Results We present a systematic characterization of spatiotemporal gene expression patterns for all known or predicted Drosophila TFs throughout embryogenesis, the first such comprehensive study for any metazoan animal. We generated RNA expression patterns for all 708 TFs by in situ hybridization, annotated the patterns using an anatomical controlled vocabulary, and analyzed TF expression in the context of organ system development. Nearly all TFs are expressed during embryogenesis and more than half are specifically expressed in the central nervous system. Compared to other genes, TFs are enriched early in the development of most organ systems, and throughout the development of the nervous system. Of the 535 TFs with spatially restricted expression, 79% are dynamically expressed in multiple organ systems while 21% show single-organ specificity. Of those expressed in multiple organ systems, 77 TFs are restricted to a single organ system either early or late in development. Expression patterns for 354 TFs are characterized for the first time in this study. Conclusions We produced a reference TF dataset for the investigation of gene regulatory networks in embryogenesis, and gained insight into the expression dynamics of the full complement of TFs controlling the development of each organ system.
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