1
|
Berg C, Sieber M, Sun J. Finishing the egg. Genetics 2024; 226:iyad183. [PMID: 38000906 PMCID: PMC10763546 DOI: 10.1093/genetics/iyad183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/27/2023] [Indexed: 11/26/2023] Open
Abstract
Gamete development is a fundamental process that is highly conserved from early eukaryotes to mammals. As germ cells develop, they must coordinate a dynamic series of cellular processes that support growth, cell specification, patterning, the loading of maternal factors (RNAs, proteins, and nutrients), differentiation of structures to enable fertilization and ensure embryonic survival, and other processes that make a functional oocyte. To achieve these goals, germ cells integrate a complex milieu of environmental and developmental signals to produce fertilizable eggs. Over the past 50 years, Drosophila oogenesis has risen to the forefront as a system to interrogate the sophisticated mechanisms that drive oocyte development. Studies in Drosophila have defined mechanisms in germ cells that control meiosis, protect genome integrity, facilitate mRNA trafficking, and support the maternal loading of nutrients. Work in this system has provided key insights into the mechanisms that establish egg chamber polarity and patterning as well as the mechanisms that drive ovulation and egg activation. Using the power of Drosophila genetics, the field has begun to define the molecular mechanisms that coordinate environmental stresses and nutrient availability with oocyte development. Importantly, the majority of these reproductive mechanisms are highly conserved throughout evolution, and many play critical roles in the development of somatic tissues as well. In this chapter, we summarize the recent progress in several key areas that impact egg chamber development and ovulation. First, we discuss the mechanisms that drive nutrient storage and trafficking during oocyte maturation and vitellogenesis. Second, we examine the processes that regulate follicle cell patterning and how that patterning impacts the construction of the egg shell and the establishment of embryonic polarity. Finally, we examine regulatory factors that control ovulation, egg activation, and successful fertilization.
Collapse
Affiliation(s)
- Celeste Berg
- Department of Genome Sciences, University of Washington, Seattle, WA 98195-5065USA
| | - Matthew Sieber
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390USA
| | - Jianjun Sun
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269USA
| |
Collapse
|
2
|
Perlmutter JI, Meyers JE, Bordenstein SR. A single synonymous nucleotide change impacts the male-killing phenotype of prophage WO gene wmk. eLife 2021; 10:67686. [PMID: 34677126 PMCID: PMC8555981 DOI: 10.7554/elife.67686] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 10/20/2021] [Indexed: 11/13/2022] Open
Abstract
Wolbachia are the most widespread bacterial endosymbionts in animals. Within arthropods, these maternally transmitted bacteria can selfishly hijack host reproductive processes to increase the relative fitness of their transmitting females. One such form of reproductive parasitism called male killing, or the selective killing of infected males, is recapitulated to degrees by transgenic expression of the prophage WO-mediated killing (wmk) gene. Here, we characterize the genotype-phenotype landscape of wmk-induced male killing in D. melanogaster using transgenic expression. While phylogenetically distant wmk homologs induce no sex-ratio bias, closely-related homologs exhibit complex phenotypes spanning no death, male death, or death of all hosts. We demonstrate that alternative start codons, synonymous codons, and notably a single synonymous nucleotide in wmk can ablate killing. These findings reveal previously unrecognized features of transgenic wmk-induced killing and establish new hypotheses for the impacts of post-transcriptional processes in male killing variation. We conclude that synonymous sequence changes are not necessarily silent in nested endosymbiotic interactions with life-or-death consequences.
Collapse
Affiliation(s)
- Jessamyn I Perlmutter
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Department of Molecular Biosciences, University of Kansas, Lawrence, United States.,Vanderbilt Microbiome Innovation Center, Vanderbilt University, Nashville, United States
| | - Jane E Meyers
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Vanderbilt Microbiome Innovation Center, Vanderbilt University, Nashville, United States
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Vanderbilt Microbiome Innovation Center, Vanderbilt University, Nashville, United States.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, United States.,Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University, Nashville, United States
| |
Collapse
|
3
|
Bradley AO, Vizcarra CL, Bailey HM, Quinlan ME. Spire stimulates nucleation by Cappuccino and binds both ends of actin filaments. Mol Biol Cell 2019; 31:273-286. [PMID: 31877067 PMCID: PMC7183766 DOI: 10.1091/mbc.e19-09-0550] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The actin nucleators Spire and Cappuccino synergize to promote actin assembly, but the mechanism of their synergy is controversial. Together these proteins promote the formation of actin meshes, which are conserved structures that regulate the establishment of oocyte polarity. Direct interaction between Spire and Cappuccino is required for oogenesis and for in vitro synergistic actin assembly. This synergy is proposed to be driven by elongation and the formation of a ternary complex at filament barbed ends, or by nucleation and interaction at filament pointed ends. To mimic the geometry of Spire and Cappuccino in vivo, we immobilized Spire on beads and added Cappuccino and actin. Barbed ends, protected by Cappuccino, grow away from the beads while pointed ends are retained, as expected for nucleation-driven synergy. We found that Spire is sufficient to bind barbed ends and retain pointed ends of actin filaments near beads and we identified Spire’s barbed-end binding domain. Loss of barbed-end binding increases nucleation by Spire and synergy with Cappuccino in bulk pyrene assays and on beads. Importantly, genetic rescue by the loss-of-function mutant indicates that barbed-end binding is not necessary for oogenesis. Thus, increased nucleation is a critical element of synergy both in vitro and in vivo.
Collapse
Affiliation(s)
- Alexander O Bradley
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095
| | - Christina L Vizcarra
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095
| | - Hannah M Bailey
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095
| | - Margot E Quinlan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
| |
Collapse
|
4
|
Wei Y, Bettedi L, Ting CY, Kim K, Zhang Y, Cai J, Lilly MA. The GATOR complex regulates an essential response to meiotic double-stranded breaks in Drosophila. eLife 2019; 8:e42149. [PMID: 31650955 PMCID: PMC6834368 DOI: 10.7554/elife.42149] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/13/2019] [Indexed: 01/18/2023] Open
Abstract
The TORC1 regulator GATOR1/SEACIT controls meiotic entry and early meiotic events in yeast. However, how metabolic pathways influence meiotic progression in metazoans remains poorly understood. Here we examine the role of the TORC1 regulators GATOR1 and GATOR2 in the response to meiotic double-stranded breaks (DSB) during Drosophila oogenesis. We find that in mutants of the GATOR2 component mio, meiotic DSBs trigger the constitutive downregulation of TORC1 activity and a permanent arrest in oocyte growth. Conversely, in GATOR1 mutants, high TORC1 activity results in the delayed repair of meiotic DSBs and the hyperactivation of p53. Unexpectedly, we found that GATOR1 inhibits retrotransposon expression in the presence of meiotic DSBs in a pathway that functions in parallel to p53. Thus, our studies have revealed a link between oocyte metabolism, the repair of meiotic DSBs and retrotransposon expression.
Collapse
Affiliation(s)
- Youheng Wei
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
- College of Bioscience and BiotechnologyYangzhou UniversityYangzhouChina
| | - Lucia Bettedi
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Chun-Yuan Ting
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Kuikwon Kim
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Yingbiao Zhang
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Jiadong Cai
- College of Bioscience and BiotechnologyYangzhou UniversityYangzhouChina
| | - Mary A Lilly
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| |
Collapse
|
5
|
Spracklen AJ, Thornton-Kolbe EM, Bonner AN, Florea A, Compton PJ, Fernandez-Gonzalez R, Peifer M. The Crk adapter protein is essential for Drosophila embryogenesis, where it regulates multiple actin-dependent morphogenic events. Mol Biol Cell 2019; 30:2399-2421. [PMID: 31318326 PMCID: PMC6741062 DOI: 10.1091/mbc.e19-05-0302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Small Src homology domain 2 (SH2) and 3 (SH3) adapter proteins regulate cell fate and behavior by mediating interactions between cell surface receptors and downstream signaling effectors in many signal transduction pathways. The CT10 regulator of kinase (Crk) family has tissue-specific roles in phagocytosis, cell migration, and neuronal development and mediates oncogenic signaling in pathways like that of Abelson kinase. However, redundancy among the two mammalian family members and the position of the Drosophila gene on the fourth chromosome precluded assessment of Crk's full role in embryogenesis. We circumvented these limitations with short hairpin RNA and CRISPR technology to assess Crk's function in Drosophila morphogenesis. We found that Crk is essential beginning in the first few hours of development, where it ensures accurate mitosis by regulating orchestrated dynamics of the actin cytoskeleton to keep mitotic spindles in syncytial embryos from colliding. In this role, it positively regulates cortical localization of the actin-related protein 2/3 complex (Arp2/3), its regulator suppressor of cAMP receptor (SCAR), and filamentous actin to actin caps and pseudocleavage furrows. Crk loss leads to the loss of nuclei and formation of multinucleate cells. We also found roles for Crk in embryonic wound healing and in axon patterning in the nervous system, where it localizes to the axons and midline glia. Thus, Crk regulates diverse events in embryogenesis that require orchestrated cytoskeletal dynamics.
Collapse
Affiliation(s)
- Andrew J Spracklen
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Emma M Thornton-Kolbe
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Alison N Bonner
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Alexandru Florea
- Institute of Biomaterials and Biomedical Engineering, Ted Rogers Centre for Heart Research, and Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Peter J Compton
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering, Ted Rogers Centre for Heart Research, and Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Mark Peifer
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| |
Collapse
|
6
|
Li Z, Zhou M, Cai Z, Liu H, Zhong W, Hao Q, Cheng D, Hu X, Hou J, Xu P, Xue Y, Zhou Y, Xu T. RNA-binding protein DDX1 is responsible for fatty acid-mediated repression of insulin translation. Nucleic Acids Res 2019; 46:12052-12066. [PMID: 30295850 PMCID: PMC6294501 DOI: 10.1093/nar/gky867] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 09/14/2018] [Indexed: 01/13/2023] Open
Abstract
The molecular mechanism in pancreatic β cells underlying hyperlipidemia and insulin insufficiency remains unclear. Here, we find that the fatty acid-induced decrease in insulin levels occurs due to a decrease in insulin translation. Since regulation at the translational level is generally mediated through RNA-binding proteins, using RNA antisense purification coupled with mass spectrometry, we identify a novel insulin mRNA-binding protein, namely, DDX1, that is sensitive to palmitate treatment. Notably, the knockdown or overexpression of DDX1 affects insulin translation, and the knockdown of DDX1 eliminates the palmitate-induced repression of insulin translation. Molecular mechanism studies show that palmitate treatment causes DDX1 phosphorylation at S295 and dissociates DDX1 from insulin mRNA, thereby leading to the suppression of insulin translation. In addition, DDX1 may interact with the translation initiation factors eIF3A and eIF4B to regulate translation. In high-fat diet mice, the inhibition of insulin translation happens at an early prediabetic stage before the elevation of glucose levels. We speculate that the DDX1-mediated repression of insulin translation worsens the situation of insulin resistance and contributes to the elevation of blood glucose levels in obese animals.
Collapse
Affiliation(s)
- Zonghong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China.,Jilin Province Key Laboratory on Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Maoge Zhou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhaokui Cai
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongyang Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Wen Zhong
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiang Hao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Dongwan Cheng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Xihao Hu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Junjie Hou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| | - Pingyong Xu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yifa Zhou
- Jilin Province Key Laboratory on Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Tao Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
7
|
Negreiros E, Herszterg S, Kang KH, Câmara A, Dias WB, Carneiro K, Bier E, Todeschini AR, Araujo H. N-linked glycosylation restricts the function of Short gastrulation to bind and shuttle BMPs. Development 2018; 145:dev.167338. [PMID: 30355725 DOI: 10.1242/dev.167338] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 08/14/2018] [Indexed: 12/11/2022]
Abstract
Disorders of N-linked glycosylation are increasingly reported in the literature. However, the targets that are responsible for the associated developmental and physiological defects are largely unknown. Bone morphogenetic proteins (BMPs) act as highly dynamic complexes to regulate several functions during development. The range and strength of BMP activity depend on interactions with glycosylated protein complexes in the extracellular milieu. Here, we investigate the role of glycosylation for the function of the conserved extracellular BMP antagonist Short gastrulation (Sog). We identify conserved N-glycosylated sites and describe the effect of mutating these residues on BMP pathway activity in Drosophila Functional analysis reveals that loss of individual Sog glycosylation sites enhances BMP antagonism and/or increases the spatial range of Sog effects in the tissue. Mechanistically, we provide evidence that N-terminal and stem glycosylation controls extracellular Sog levels and distribution. The identification of similar residues in vertebrate Chordin proteins suggests that N-glycosylation may be an evolutionarily conserved process that adds complexity to the regulation of BMP activity.
Collapse
Affiliation(s)
- Erika Negreiros
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Sophie Herszterg
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Kyung-Hwa Kang
- Division of Biological Sciences, University of California at San Diego, CA 92093-0349, USA
| | - Amanda Câmara
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Wagner B Dias
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Katia Carneiro
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Ethan Bier
- Division of Biological Sciences, University of California at San Diego, CA 92093-0349, USA
| | - Adriane Regina Todeschini
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902
| | - Helena Araujo
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil, 21941-902 .,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Brasil (INCT-ENEM)
| |
Collapse
|
8
|
Takeda M, Sami MM, Wang YC. A homeostatic apical microtubule network shortens cells for epithelial folding via a basal polarity shift. Nat Cell Biol 2017; 20:36-45. [PMID: 29203884 DOI: 10.1038/s41556-017-0001-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 09/19/2017] [Indexed: 12/27/2022]
Abstract
Epithelial folding is typically driven by localized actomyosin contractility. However, it remains unclear how epithelia deform when myosin levels are low and uniform. In the Drosophila gastrula, dorsal fold formation occurs despite a lack of localized myosin changes, while the fold-initiating cells reduce cell height following basal shifts of polarity via an unknown mechanism. We show that cell shortening depends on an apical microtubule network organized by the CAMSAP protein Patronin. Prior to gastrulation, microtubule forces generated by the minus-end motor dynein scaffold the apical cell cortex into a dome-like shape, while the severing enzyme Katanin facilitates network remodelling to ensure tissue-wide cell size homeostasis. During fold initiation, Patronin redistributes following basal polarity shifts in the initiating cells, apparently weakening the scaffolding forces to allow dome descent. The homeostatic network that ensures size/shape homogeneity is thus repurposed for cell shortening, linking epithelial polarity to folding via a microtubule-based mechanical mechanism.
Collapse
Affiliation(s)
- Michiko Takeda
- Laboratory for Epithelial Morphogenesis, RIKEN Center for Developmental Biology, Kobe, Hyogo, Japan
| | - Mustafa M Sami
- Laboratory for Epithelial Morphogenesis, RIKEN Center for Developmental Biology, Kobe, Hyogo, Japan
| | - Yu-Chiun Wang
- Laboratory for Epithelial Morphogenesis, RIKEN Center for Developmental Biology, Kobe, Hyogo, Japan.
| |
Collapse
|
9
|
Song Y, Marmion RA, Park JO, Biswas D, Rabinowitz JD, Shvartsman SY. Dynamic Control of dNTP Synthesis in Early Embryos. Dev Cell 2017; 42:301-308.e3. [PMID: 28735680 DOI: 10.1016/j.devcel.2017.06.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/13/2017] [Accepted: 06/16/2017] [Indexed: 02/06/2023]
Abstract
Exponential increase of cell numbers in early embryos requires large amounts of DNA precursors (deoxyribonucleoside triphosphates (dNTPs)). Little is understood about how embryos satisfy this demand. We examined dNTP metabolism in the early Drosophila embryo, in which gastrulation is preceded by 13 sequential nuclear cleavages within only 2 hr of fertilization. Surprisingly, despite the breakneck speed at which Drosophila embryos synthesize DNA, maternally deposited dNTPs can generate less than half of the genomes needed to reach gastrulation. The rest of the dNTPs are synthesized "on the go." The rate-limiting enzyme of dNTP synthesis, ribonucleotide reductase, is inhibited by endogenous levels of deoxyATP (dATP) present at fertilization and is activated as dATP is depleted via DNA polymerization. This feedback inhibition renders the concentration of dNTPs at gastrulation robust, with respect to large variations in maternal supplies, and is essential for normal progression of embryogenesis.
Collapse
Affiliation(s)
- Yonghyun Song
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Robert A Marmion
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Junyoung O Park
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Debopriyo Biswas
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Joshua D Rabinowitz
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Stanislav Y Shvartsman
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
| |
Collapse
|
10
|
Johnson HE, Goyal Y, Pannucci NL, Schüpbach T, Shvartsman SY, Toettcher JE. The Spatiotemporal Limits of Developmental Erk Signaling. Dev Cell 2017; 40:185-192. [PMID: 28118601 DOI: 10.1016/j.devcel.2016.12.002] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/30/2016] [Accepted: 12/01/2016] [Indexed: 11/28/2022]
Abstract
Animal development is characterized by signaling events that occur at precise locations and times within the embryo, but determining when and where such precision is needed for proper embryogenesis has been a long-standing challenge. Here we address this question for extracellular signal regulated kinase (Erk) signaling, a key developmental patterning cue. We describe an optogenetic system for activating Erk with high spatiotemporal precision in vivo. Implementing this system in Drosophila, we find that embryogenesis is remarkably robust to ectopic Erk signaling, except from 1 to 4 hr post-fertilization, when perturbing the spatial extent of Erk pathway activation leads to dramatic disruptions of patterning and morphogenesis. Later in development, the effects of ectopic signaling are buffered, at least in part, by combinatorial mechanisms. Our approach can be used to systematically probe the differential contributions of the Ras/Erk pathway and concurrent signals, leading to a more quantitative understanding of developmental signaling.
Collapse
Affiliation(s)
- Heath E Johnson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Yogesh Goyal
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Nicole L Pannucci
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Trudi Schüpbach
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Stanislav Y Shvartsman
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| |
Collapse
|
11
|
Gonskikh Y, Polacek N. Alterations of the translation apparatus during aging and stress response. Mech Ageing Dev 2017; 168:30-36. [PMID: 28414025 DOI: 10.1016/j.mad.2017.04.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 03/28/2017] [Accepted: 04/10/2017] [Indexed: 01/03/2023]
Abstract
Aging is a biological process characterized by the irreversible and time-dependent deterioration of cell functions, tissues, and organs. Accumulating studies in a wide range of species from yeast to human revealed changes associated with the aging process to be conserved throughout evolution. The main characteristics of aging are (i) genomic instability, (ii) loss of telomere function, (iii) epigenetic changes,(iv) increased cellular senescence, (v) depletion of the stem cell pool, (vi) altered intercellular communication and (vii) loss of protein homeostasis. Among the multiple molecular mechanisms underlying aging, alterations of the translation machinery affecting the rate and selectivity of protein biosynthesis seem to play a central role. At the very heart of translation is the ribosome, a multifaceted and universally conserved RNA-protein particle responsible for accurate polypeptide synthesis and co-translational protein folding. Here we summarize and discuss recent developments on the contribution of altered translation and age-dependent modifications on the ribosome structure to aging and cellular senescence.
Collapse
Affiliation(s)
- Yulia Gonskikh
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Norbert Polacek
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
| |
Collapse
|
12
|
Goyal Y, Jindal GA, Pelliccia JL, Yamaya K, Yeung E, Futran AS, Burdine RD, Schüpbach T, Shvartsman SY. Divergent effects of intrinsically active MEK variants on developmental Ras signaling. Nat Genet 2017; 49:465-469. [PMID: 28166211 PMCID: PMC5621734 DOI: 10.1038/ng.3780] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 12/30/2016] [Indexed: 12/16/2022]
Abstract
Germline mutations in Ras pathway components are associated with a large class of human developmental abnormalities, known as RASopathies, that are characterized by a range of structural and functional phenotypes, including cardiac defects and neurocognitive delays. Although it is generally believed that RASopathies are caused by altered levels of pathway activation, the signaling changes in developing tissues remain largely unknown. We used assays with spatiotemporal resolution in Drosophila melanogaster (fruit fly) and Danio rerio (zebrafish) to quantify signaling changes caused by mutations in MAP2K1 (encoding MEK), a core component of the Ras pathway that is mutated in both RASopathies and cancers in humans. Surprisingly, we discovered that intrinsically active MEK variants can both increase and reduce the levels of pathway activation in vivo. The sign of the effect depends on cellular context, implying that some of the emerging phenotypes in RASopathies may be caused by increased, as well as attenuated, levels of Ras signaling.
Collapse
Affiliation(s)
- Yogesh Goyal
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Granton A. Jindal
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - José L. Pelliccia
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Kei Yamaya
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Eyan Yeung
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Alan S. Futran
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Rebecca D. Burdine
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Trudi Schüpbach
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Stanislav Y. Shvartsman
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| |
Collapse
|
13
|
Prophage WO genes recapitulate and enhance Wolbachia-induced cytoplasmic incompatibility. Nature 2017; 543:243-247. [PMID: 28241146 PMCID: PMC5358093 DOI: 10.1038/nature21391] [Citation(s) in RCA: 286] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 01/12/2017] [Indexed: 02/05/2023]
Abstract
The genus Wolbachia is an archetype of maternally inherited intracellular bacteria that infect the germline of numerous invertebrate species worldwide. They can selfishly alter arthropod sex ratios and reproductive strategies to increase the proportion of the infected matriline in the population. The most common reproductive manipulation is cytoplasmic incompatibility (CI), which results in embryonic lethality in crosses between infected males and uninfected females. Females infected with the same Wolbachia strain rescue this lethality. Despite more than 40 years of research1 and relevance to symbiont-induced speciation2,3, as well as control of arbovirus vectors4,5,6 and agricultural pests7, the bacterial genes underlying CI remain unknown. Here, we use comparative and transgenic approaches to demonstrate that two differentially transcribed, codiverging genes in the eukaryotic association module of prophage WO8 from Wolbachia strain wMel recapitulate and enhance CI. Dual expression in transgenic, uninfected males of Drosophila melanogaster crossed to uninfected females causes embryonic lethality. Each gene additively augments embryonic lethality in infected males crossed to uninfected females. Lethality associates with embryonic defects that parallel those of wild type CI and is notably rescued by wMel-infected embryos in all cases. The discovery of cytoplasmic incompatibility factor genes cifA and cifB pioneers genetic studies of prophage WO-induced reproductive manipulations and informs Wolbachia’s ongoing utility to control dengue and Zika transmission to humans.
Collapse
|
14
|
In vivo severity ranking of Ras pathway mutations associated with developmental disorders. Proc Natl Acad Sci U S A 2017; 114:510-515. [PMID: 28049852 DOI: 10.1073/pnas.1615651114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Germ-line mutations in components of the Ras/MAPK pathway result in developmental disorders called RASopathies, affecting about 1/1,000 human births. Rapid advances in genome sequencing make it possible to identify multiple disease-related mutations, but there is currently no systematic framework for translating this information into patient-specific predictions of disease progression. As a first step toward addressing this issue, we developed a quantitative, inexpensive, and rapid framework that relies on the early zebrafish embryo to assess mutational effects on a common scale. Using this assay, we assessed 16 mutations reported in MEK1, a MAPK kinase, and provide a robust ranking of these mutations. We find that mutations found in cancer are more severe than those found in both RASopathies and cancer, which, in turn, are generally more severe than those found only in RASopathies. Moreover, this rank is conserved in other zebrafish embryonic assays and Drosophila-specific embryonic and adult assays, suggesting that our ranking reflects the intrinsic property of the mutant molecule. Furthermore, this rank is predictive of the drug dose needed to correct the defects. This assay can be readily used to test the strengths of existing and newly found mutations in MEK1 and other pathway components, providing the first step in the development of rational guidelines for patient-specific diagnostics and treatment of RASopathies.
Collapse
|
15
|
Musashe DT, Purice MD, Speese SD, Doherty J, Logan MA. Insulin-like Signaling Promotes Glial Phagocytic Clearance of Degenerating Axons through Regulation of Draper. Cell Rep 2016; 16:1838-50. [PMID: 27498858 DOI: 10.1016/j.celrep.2016.07.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 05/23/2016] [Accepted: 07/09/2016] [Indexed: 01/15/2023] Open
Abstract
Neuronal injury triggers robust responses from glial cells, including altered gene expression and enhanced phagocytic activity to ensure prompt removal of damaged neurons. The molecular underpinnings of glial responses to trauma remain unclear. Here, we find that the evolutionarily conserved insulin-like signaling (ILS) pathway promotes glial phagocytic clearance of degenerating axons in adult Drosophila. We find that the insulin-like receptor (InR) and downstream effector Akt1 are acutely activated in local ensheathing glia after axotomy and are required for proper clearance of axonal debris. InR/Akt1 activity, it is also essential for injury-induced activation of STAT92E and its transcriptional target draper, which encodes a conserved receptor essential for glial engulfment of degenerating axons. Increasing Draper levels in adult glia partially rescues delayed clearance of severed axons in glial InR-inhibited flies. We propose that ILS functions as a key post-injury communication relay to activate glial responses, including phagocytic activity.
Collapse
Affiliation(s)
- Derek T Musashe
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239, USA
| | - Maria D Purice
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239, USA
| | - Sean D Speese
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239, USA
| | - Johnna Doherty
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, 55 North Lake Avenue, Worcester, MA 01605, USA
| | - Mary A Logan
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health and Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239, USA.
| |
Collapse
|
16
|
The multiple functions of RNA helicases as drivers and regulators of gene expression. Nat Rev Mol Cell Biol 2016; 17:426-38. [PMID: 27251421 DOI: 10.1038/nrm.2016.50] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
RNA helicases comprise the largest family of enzymes involved in the metabolism of mRNAs, the processing and fate of which rely on their packaging into messenger ribonucleoprotein particles (mRNPs). In this Review, we describe how the capacity of some RNA helicases to either remodel or lock the composition of mRNP complexes underlies their pleiotropic functions at different steps of the gene expression process. We illustrate the roles of RNA helicases in coordinating gene expression steps and programmes, and propose that RNA helicases function as molecular drivers and guides of the progression of their mRNA substrates from one RNA-processing factory to another, to a productive mRNA pool that leads to protein synthesis or to unproductive mRNA pools that are stored or degraded.
Collapse
|
17
|
Guo Z, Batiha O, Bourouh M, Fifield E, Swan A. Role of Securin, Separase and Cohesins in female meiosis and polar body formation in Drosophila. J Cell Sci 2016; 129:531-42. [PMID: 26675236 DOI: 10.1242/jcs.179358] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/08/2015] [Indexed: 11/20/2022] Open
Abstract
Chromosome segregation in meiosis is controlled by a conserved pathway that culminates in Separase-mediated cleavage of the α-kleisin Rec8, leading to dissolution of cohesin rings. Drosophila has no gene encoding Rec8, and the absence of a known Separase target raises the question of whether Separase and its regulator Securin (Pim in Drosophila) are important in Drosophila meiosis. Here, we investigate the role of Securin, Separase and the cohesin complex in female meiosis using fluorescence in situ hybridization against centromeric and arm-specific sequences to monitor cohesion. We show that Securin destruction and Separase activity are required for timely release of arm cohesion in anaphase I and centromere-proximal cohesion in anaphase II. They are also required for release of arm cohesion on polar body chromosomes. Cohesion on polar body chromosomes depends on the cohesin components SMC3 and the mitotic α-kleisin Rad21 (also called Vtd in Drosophila). We provide cytological evidence that SMC3 is required for arm cohesion in female meiosis, whereas Rad21, in agreement with recent findings, is not. We conclude that in Drosophila meiosis, cohesion is regulated by a conserved Securin-Separase pathway that targets a diverged Separase target, possibly within the cohesin complex.
Collapse
Affiliation(s)
- Zhihao Guo
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 2P1
| | - Osamah Batiha
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 2P1
| | - Mohammed Bourouh
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 2P1
| | - Eric Fifield
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 2P1
| | - Andrew Swan
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B 2P1
| |
Collapse
|
18
|
Bor B, Bois JS, Quinlan ME. Regulation of the formin Cappuccino is critical for polarity of Drosophila oocytes. Cytoskeleton (Hoboken) 2015; 72:1-15. [PMID: 25557988 DOI: 10.1002/cm.21205] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 12/19/2014] [Indexed: 11/06/2022]
Abstract
The Drosophila formin Cappuccino (Capu) creates an actin mesh-like structure that traverses the oocyte during midoogenesis. This mesh is thought to prevent premature onset of fast cytoplasmic streaming which normally happens during late-oogenesis. Proper cytoskeletal organization and cytoplasmic streaming are crucial for localization of polarity determinants such as osk, grk, bcd, and nanos mRNAs. Capu mutants disrupt these events, leading to female sterility. Capu is regulated by another nucleator, Spire, as well as by autoinhibition in vitro. Studies in vivo confirm that Spire modulates Capu's function in oocytes; however, how autoinhibition contributes is still unclear. To study the role of autoinhibition in flies, we expressed a Capu construct that is missing the Capu Inhibitory Domain, CapuΔN. Consistent with a gain of activity due to loss of autoinhibition, the actin mesh was denser in CapuΔN oocytes. Further, cytoplasmic streaming was delayed and fertility levels decreased. Localization of osk mRNA in early stages, and bcd and nanos in late stages, were disrupted in CapuΔN-expressing oocytes. Finally, evidence that these phenotypes were due to a loss of autoinhibition comes from coexpression of the N-terminal half of Capu with CapuΔN, which suppressed the defects in actin, cytoplasmic streaming and fertility. From these results, we conclude that Capu can be autoinhibited during Drosophila oocyte development.
Collapse
Affiliation(s)
- Batbileg Bor
- Molecular Biology Interdepartmental PhD Program, University of California, Los Angeles, California, 90095-1570
| | | | | |
Collapse
|
19
|
Li W, Klovstad M, Schüpbach T. Repression of Gurken translation by a meiotic checkpoint in Drosophila oogenesis is suppressed by a reduction in the dose of eIF1A. Development 2014; 141:3910-21. [PMID: 25231760 DOI: 10.1242/dev.109306] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In Drosophila melanogaster, the anteroposterior (AP) and dorsoventral (DV) axes of the oocyte and future embryo are established through the localization and translational regulation of gurken (grk) mRNA. This process involves binding of specific factors to the RNA during transport and a dynamic remodeling of the grk-containing ribonucleoprotein (RNP) complexes once they have reached their destination within the oocyte. In ovaries of spindle-class females, an activated DNA damage checkpoint causes inefficient Grk translation and ventralization of the oocyte. In a screen for modifiers of the oocyte DV patterning defects, we identified a mutation in the eIF1A gene as a dominant suppressor. We show that reducing the function of eIF1A in spnB ovaries suppresses the ventralized eggshell phenotype by restoring Grk expression. This suppression is not the result of more efficient DNA damage repair or of disrupted checkpoint activation, but is coupled to an increase in the amount of grk mRNA associated with polysomes. In spnB ovaries, the activated meiotic checkpoint blocks Grk translation by disrupting the accumulation of grk mRNA in a translationally competent RNP complex that contains the translational activator Oo18 RNA-binding protein (Orb); this regulation involves the translational repressor Squid (Sqd). We further propose that reduction of eIF1A allows more efficient Grk translation possibly because of the presence of specific structural features in the grk 5'UTR.
Collapse
Affiliation(s)
- Wei Li
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Martha Klovstad
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Trudi Schüpbach
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| |
Collapse
|
20
|
Quinlan ME. Direct interaction between two actin nucleators is required in Drosophila oogenesis. Development 2013; 140:4417-25. [PMID: 24089467 DOI: 10.1242/dev.097337] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Controlled actin assembly is crucial to a wide variety of cellular processes, including polarity establishment during early development. The recently discovered actin mesh, a structure that traverses the Drosophila oocyte during mid-oogenesis, is essential for proper establishment of the major body axes. Genetic experiments indicate that at least two proteins, Spire (Spir) and Cappuccino (Capu), are required to build this mesh. The spire and cappuccino genetic loci were first identified as maternal effect genes in Drosophila. Mutation in either locus results in the same phenotypes, including absence of the mesh, linking them functionally. Both proteins nucleate actin filaments. Spir and Capu also interact directly with each other in vitro, suggesting a novel synergistic mode of regulating actin. In order to understand how and why proteins with similar biochemical activity would be required in the same biological pathway, genetic experiments were designed to test whether a direct interaction between Spir and Capu is required during oogenesis. Indeed, data in this study indicate that Spir and Capu must interact directly with one another and then separate to function properly. Furthermore, these actin regulators are controlled by a combination of mechanisms, including interaction with one another, functional inhibition and regulation of their protein levels. Finally, this work demonstrates for the first time in a multicellular organism that the ability of a formin to assemble actin filaments is required for a specific structure.
Collapse
Affiliation(s)
- Margot E Quinlan
- Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California Los Angeles, 607 Charles E. Young Drive, Los Angeles, CA 90095, USA
| |
Collapse
|
21
|
Fontenele M, Lim B, Oliveira D, Buffolo M, Perlman DH, Schupbach T, Araujo H. Calpain A modulates Toll responses by limited Cactus/IκB proteolysis. Mol Biol Cell 2013; 24:2966-80. [PMID: 23864715 PMCID: PMC3771957 DOI: 10.1091/mbc.e13-02-0113] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Calcium-dependent cysteine proteases of the calpain family are modulatory proteases that cleave their substrates in a limited manner. Among their substrates, calpains target vertebrate and invertebrate IκB proteins. Because proteolysis by calpains potentially generates novel protein functions, it is important to understand how this affects NFκB activity. We investigate the action of Calpain A (CalpA) on the Drosophila melanogaster IκB homologue Cactus in vivo. CalpA alters the absolute amounts of Cactus protein. Our data indicate, however, that CalpA uses additional mechanisms to regulate NFκB function. We provide evidence that CalpA interacts physically with Cactus, recognizing a Cactus pool that is not bound to Dorsal, a fly NFκB/Rel homologue. We show that proteolytic cleavage by CalpA generates Cactus fragments lacking an N-terminal region required for Toll responsiveness. These fragments are generated in vivo and display properties distinct from those of full-length Cactus. We propose that CalpA targets free Cactus, which is incorporated into and modulates Toll-responsive complexes in the embryo and immune system.
Collapse
Affiliation(s)
- Marcio Fontenele
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, CEP 21941-902 Rio de Janeiro, Brazil Chemistry Institute, Federal University of Rio de Janeiro, CEP 21941-902 Rio de Janeiro, Brazil Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544 Princeton Collaborative Proteomics and Mass Spectrometry Center, Princeton University, Princeton, NJ 08544 Molecular Biology Department, Princeton University, Princeton, NJ 08544 Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | | | | | | | | | | | | |
Collapse
|
22
|
Wang YC, Khan Z, Wieschaus EF. Distinct Rap1 activity states control the extent of epithelial invagination via α-catenin. Dev Cell 2013; 25:299-309. [PMID: 23623612 DOI: 10.1016/j.devcel.2013.04.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 03/08/2013] [Accepted: 04/01/2013] [Indexed: 11/16/2022]
Abstract
Localized cell shape change initiates epithelial folding, while neighboring cell invagination determines the final depth of an epithelial fold. The mechanism that controls the extent of invagination remains unknown. During Drosophila gastrulation, a higher number of cells undergo invagination to form the deep posterior dorsal fold, whereas far fewer cells become incorporated into the initially very similar anterior dorsal fold. We find that a decrease in α-catenin activity causes the anterior fold to invaginate as extensively as the posterior fold. In contrast, constitutive activation of the small GTPase Rap1 restricts invagination of both dorsal folds in an α-catenin-dependent manner. Rap1 activity appears spatially modulated by Rapgap1, whose expression levels are high in the cells that flank the posterior fold but low in the anterior fold. We propose a model whereby distinct activity states of Rap1 modulate α-catenin-dependent coupling between junctions and actin to control the extent of epithelial invagination.
Collapse
Affiliation(s)
- Yu-Chiun Wang
- Department of Molecular Biology, Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA
| | | | | |
Collapse
|
23
|
Ferguson SB, Blundon MA, Klovstad MS, Schüpbach T. Modulation of gurken translation by insulin and TOR signaling in Drosophila. Development 2012. [DOI: 10.1242/dev.083451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|