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McGehee J, Stathopoulos A. Target gene responses differ when transcription factor levels are acutely decreased by nuclear export versus degradation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.595009. [PMID: 38826476 PMCID: PMC11142056 DOI: 10.1101/2024.05.20.595009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Defining the time of action for morphogens requires tools capable of temporally controlled perturbations. To study how the transcription factor Dorsal affects patterning of the Drosophila embryonic dorsal-ventral axis, we used two light-inducible tags that result in either nuclear export or degradation of Dorsal when exposed to blue light. Nuclear export of Dorsal results in loss of expression for the high threshold, ventrally-expressed target gene snail (sna) but retention of the low threshold, laterally-expressed target gene short-gastrulation (sog). In contrast, degradation of Dorsal results in retention of sna, loss of sog, and lower nuclear levels than when Dorsal is exported from the nucleus. To elucidate how nuclear export results in loss of sna but degradation does not, we investigated Dorsal kinetics using photobleaching and found it reenters the nucleus even under conditions of blue-light when export is favored. The associated kinetics of being imported and exported continuously are likely responsible for loss of sna but, alternatively, can support sog. Collectively, our results show that this dynamic patterning process is influenced by both Dorsal concentration and nuclear retention.
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Affiliation(s)
- James McGehee
- California Institute of Technology, Division of Biology and Biological Engineering, 1200 East California Boulevard, Pasadena, CA 91125
| | - Angelike Stathopoulos
- California Institute of Technology, Division of Biology and Biological Engineering, 1200 East California Boulevard, Pasadena, CA 91125
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2
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Auxillos J, Crouigneau R, Li YF, Dai Y, Stigliani A, Tavernaro I, Resch-Genger U, Sandelin A, Marie R, Pedersen SF. Spatially resolved analysis of microenvironmental gradient impact on cancer cell phenotypes. SCIENCE ADVANCES 2024; 10:eadn3448. [PMID: 38701211 PMCID: PMC11068013 DOI: 10.1126/sciadv.adn3448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 04/02/2024] [Indexed: 05/05/2024]
Abstract
Despite the physiological and pathophysiological significance of microenvironmental gradients, e.g., for diseases such as cancer, tools for generating such gradients and analyzing their impact are lacking. Here, we present an integrated microfluidic-based workflow that mimics extracellular pH gradients characteristic of solid tumors while enabling high-resolution live imaging of, e.g., cell motility and chemotaxis, and preserving the capacity to capture the spatial transcriptome. Our microfluidic device generates a pH gradient that can be rapidly controlled to mimic spatiotemporal microenvironmental changes over cancer cells embedded in a 3D matrix. The device can be reopened allowing immunofluorescence analysis of selected phenotypes, as well as the transfer of cells and matrix to a Visium slide for spatially resolved analysis of transcriptional changes across the pH gradient. This workflow is easily adaptable to other gradients and multiple cell types and can therefore prove invaluable for integrated analysis of roles of microenvironmental gradients in biology.
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Affiliation(s)
- Jamie Auxillos
- Section for Computational and RNA biology, Department of Biology, University of Copenhagen, Denmark
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Denmark
| | - Roxane Crouigneau
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Denmark
| | - Yan-Fang Li
- Department of Health Technology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Yifan Dai
- Section for Computational and RNA biology, Department of Biology, University of Copenhagen, Denmark
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Denmark
| | - Arnaud Stigliani
- Section for Computational and RNA biology, Department of Biology, University of Copenhagen, Denmark
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Denmark
| | - Isabella Tavernaro
- Division Biophotonics, Bundesanstalt für Materialforschung und -prüfung, Richard-Willstaetter Str. 11, 12489, Berlin, Germany
| | - Ute Resch-Genger
- Division Biophotonics, Bundesanstalt für Materialforschung und -prüfung, Richard-Willstaetter Str. 11, 12489, Berlin, Germany
| | - Albin Sandelin
- Section for Computational and RNA biology, Department of Biology, University of Copenhagen, Denmark
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Denmark
| | - Rodolphe Marie
- Department of Health Technology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Stine F. Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Denmark
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3
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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.
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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
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Roth S. Neofunctionalization of Toll Signaling in Insects: From Immunity to Dorsoventral Patterning. Annu Rev Cell Dev Biol 2023; 39:1-22. [PMID: 37843930 DOI: 10.1146/annurev-cellbio-120319-120223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Toll signaling plays a crucial role in pathogen defense throughout the animal kingdom. It was discovered, however, for its function in dorsoventral (DV) axis formation in Drosophila. In all other insects studied so far, but not outside the insects, Toll is also required for DV patterning. However, in insects more distantly related to Drosophila, Toll's patterning role is frequently reduced and substituted by an expanded influence of BMP signaling, the pathway implicated in DV axis formation in all major metazoan lineages. This suggests that Toll was integrated into an ancestral BMP-based patterning system at the base of the insects or during insect evolution. The observation that Toll signaling has an immune function in the extraembryonic serosa, an early differentiating tissue of most insect embryos, suggests a scenario of how Toll was co-opted from an ancestral immune function for its new role in axis formation.
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Affiliation(s)
- Siegfried Roth
- Institute of Zoology-Developmental Biology, Biocenter, University of Cologne, Cologne, Germany;
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5
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Yang Q, Lo TW, Brejc K, Schartner C, Ralston EJ, Lapidus DM, Meyer BJ. X-chromosome target specificity diverged between dosage compensation mechanisms of two closely related Caenorhabditis species. eLife 2023; 12:e85413. [PMID: 36951246 PMCID: PMC10076027 DOI: 10.7554/elife.85413] [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: 12/07/2022] [Accepted: 03/21/2023] [Indexed: 03/24/2023] Open
Abstract
An evolutionary perspective enhances our understanding of biological mechanisms. Comparison of sex determination and X-chromosome dosage compensation mechanisms between the closely related nematode species Caenorhabditis briggsae (Cbr) and Caenorhabditis elegans (Cel) revealed that the genetic regulatory hierarchy controlling both processes is conserved, but the X-chromosome target specificity and mode of binding for the specialized condensin dosage compensation complex (DCC) controlling X expression have diverged. We identified two motifs within Cbr DCC recruitment sites that are highly enriched on X: 13 bp MEX and 30 bp MEX II. Mutating either MEX or MEX II in an endogenous recruitment site with multiple copies of one or both motifs reduced binding, but only removing all motifs eliminated binding in vivo. Hence, DCC binding to Cbr recruitment sites appears additive. In contrast, DCC binding to Cel recruitment sites is synergistic: mutating even one motif in vivo eliminated binding. Although all X-chromosome motifs share the sequence CAGGG, they have otherwise diverged so that a motif from one species cannot function in the other. Functional divergence was demonstrated in vivo and in vitro. A single nucleotide position in Cbr MEX can determine whether Cel DCC binds. This rapid divergence of DCC target specificity could have been an important factor in establishing reproductive isolation between nematode species and contrasts dramatically with the conservation of target specificity for X-chromosome dosage compensation across Drosophila species and for transcription factors controlling developmental processes such as body-plan specification from fruit flies to mice.
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Affiliation(s)
- Qiming Yang
- Howard Hughes Medical InstituteBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Te-Wen Lo
- Howard Hughes Medical InstituteBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Katjuša Brejc
- Howard Hughes Medical InstituteBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Caitlin Schartner
- Howard Hughes Medical InstituteBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Edward J Ralston
- Howard Hughes Medical InstituteBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Denise M Lapidus
- Howard Hughes Medical InstituteBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Barbara J Meyer
- Howard Hughes Medical InstituteBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
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Xue Y, Krishnan A, Chahda JS, Schweickart RA, Sousa-Neves R, Mizutani CM. The epithelial polarity genes frazzled and GUK-holder adjust morphogen gradients to coordinate changes in cell position with cell fate specification. PLoS Biol 2023; 21:e3002021. [PMID: 36913435 PMCID: PMC10035841 DOI: 10.1371/journal.pbio.3002021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 03/23/2023] [Accepted: 02/03/2023] [Indexed: 03/14/2023] Open
Abstract
Morphogenetic gradients specify distinct cell populations within tissues. Originally, morphogens were conceived as substances that act on a static field of cells, yet cells usually move during development. Thus, the way cell fates are defined in moving cells remains a significant and largely unsolved problem. Here, we investigated this issue using spatial referencing of cells and 3D spatial statistics in the Drosophila blastoderm to reveal how cell density responds to morphogenetic activity. We show that the morphogen decapentaplegic (DPP) attracts cells towards its peak levels in the dorsal midline, whereas dorsal (DL) stalls them ventrally. We identified frazzled and GUK-holder as the downstream effectors regulated by these morphogens that constrict cells and provide the mechanical force necessary to draw cells dorsally. Surprisingly, GUKH and FRA modulate the DL and DPP gradient levels and this regulation creates a very precise mechanism of coordinating cell movement and fate specification.
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Affiliation(s)
- Yongqiang Xue
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Aravindan Krishnan
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Juan Sebastian Chahda
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Robert Allen Schweickart
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Rui Sousa-Neves
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Claudia Mieko Mizutani
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
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7
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Chahda JS, Ambrosi P, Mizutani CM. The nested embryonic dorsal domains of BMP-target genes are not scaled to size during the evolution of Drosophila species. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:131-142. [PMID: 35451554 PMCID: PMC9587137 DOI: 10.1002/jez.b.23137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 03/21/2022] [Accepted: 04/03/2022] [Indexed: 11/08/2022]
Abstract
Egg size is a fast-evolving trait among Drosophilids expected to change the spatial distribution of morphogens that pattern the embryonic axes. Here we asked whether the patterning of the dorsal region of the embryo by the Decapentaplegic/Bone Morphogenetic Protein-4 (DPP/BMP-4) gradient is scaled among Drosophila species with different egg sizes. This region specifies the extra-embryonic tissue amnioserosa and the ectoderm. We find that the entire dorsal region scales with embryo size, but the gene expression patterns regulated by DPP are not proportional, suggesting that the DPP gradient is differentially scaled during evolution. To further test whether the DPP gradient can scale or not in Drosophila melanogaster, we created embryos with expanded dorsal regions that mimic changes in scale seen in other species and measured the resulting domains of DPP-target genes. We find that the proportions of these domains are not maintained, suggesting that the DPP gradient is unable to scale in the embryo. These and previous findings suggest that the embryonic dorso-ventral patterning lack scaling in the ventral and dorsal sides but is robust in the lateral region where the neuroectoderm is specified and two opposing gradients, Dorsal/NFkappa-B and DPP, intersect. We propose that the lack of scaling of the DPP gradient may contribute to changes in the size of the amnioserosa and the numbers of ectodermal cells with specific cortical tensions, which are expected to generate distinct mechanical forces for gastrulating embryos of different sizes.
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Affiliation(s)
- Juan Sebastian Chahda
- Department of Biology, College of Arts and Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Priscilla Ambrosi
- Department of Biology, College of Arts and Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Claudia Mieko Mizutani
- Department of Biology, College of Arts and Sciences, Case Western Reserve University, Cleveland, Ohio, USA.,Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Corresponding author:
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8
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Hegde S, Sreejan A, Gadgil CJ, Ratnaparkhi GS. SUMOylation of Dorsal attenuates Toll/NF-κB signaling. Genetics 2022; 221:iyac081. [PMID: 35567478 PMCID: PMC9252280 DOI: 10.1093/genetics/iyac081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 05/03/2022] [Indexed: 11/29/2022] Open
Abstract
In Drosophila, Toll/NF-κB signaling plays key roles in both animal development and in host defense. The activation, intensity, and kinetics of Toll signaling are regulated by posttranslational modifications such as phosphorylation, SUMOylation, or ubiquitination that target multiple proteins in the Toll/NF-κB cascade. Here, we have generated a CRISPR-Cas9 edited Dorsal (DL) variant that is SUMO conjugation resistant. Intriguingly, embryos laid by dlSCR mothers overcome dl haploinsufficiency and complete the developmental program. This ability appears to be a result of higher transcriptional activation by DLSCR. In contrast, SUMOylation dampens DL transcriptional activation, ultimately conferring robustness to the dorso-ventral program. In the larval immune response, dlSCR animals show an increase in crystal cell numbers, stronger activation of humoral defense genes, and high cactus levels. A mathematical model that evaluates the contribution of the small fraction of SUMOylated DL (1-5%) suggests that it acts to block transcriptional activation, which is driven primarily by DL that is not SUMO conjugated. Our findings define SUMO conjugation as an important regulator of the Toll signaling cascade, in both development and host defense. Our results broadly suggest that SUMO attenuates DL at the level of transcriptional activation. Furthermore, we hypothesize that SUMO conjugation of DL may be part of a Ubc9-dependent mechanism that restrains Toll/NF-κB signaling.
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Affiliation(s)
- Sushmitha Hegde
- Biology, Indian Institute of Science Education & Research, Pune 411008, India
| | - Ashley Sreejan
- Chemical Engineering and Process Development Division, CSIR—National Chemical Laboratory, Pune 411008, India
| | - Chetan J Gadgil
- Chemical Engineering and Process Development Division, CSIR—National Chemical Laboratory, Pune 411008, India
- CSIR—Institute of Genomics and Integrative Biology, New Delhi 110020, India
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9
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Bressan D, Araujo HM. Evolution of the dorsoventral axis in insects: the changing role of Bone Morphogenetic Proteins. CURRENT OPINION IN INSECT SCIENCE 2022; 49:1-7. [PMID: 34607082 DOI: 10.1016/j.cois.2021.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
Embryonic dorsal-ventral (DV) patterning by Bone Morphogenetic Proteins (BMPs) is a conserved feature of Bilateria, based on graded BMP activity set up by diffusible BMP ligands and Chordin/Sog antagonists. In the fly Drosophila melanogaster BMP function is secondary to patterning by the Toll pathway, suggesting a more restricted role for BMPs in insects. With widespread genome sequencing technologies allied to functional analysis in a growing number of species, recent work has shown that BMP's role in DV patterning relative to Toll varies among insect orders. Further, the role of BMP antagonists to set up BMP gradients is also greatly diversified. Here we review the recent findings concerning the role of BMP in the DV patterning of insects and address the potential aspects that may have co-evolved with BMPs to attain this functional divergence.
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Affiliation(s)
- Daniel Bressan
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Helena Marcolla Araujo
- Institute for Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
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10
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Pechmann M, Kenny NJ, Pott L, Heger P, Chen YT, Buchta T, Özüak O, Lynch J, Roth S. Striking parallels between dorsoventral patterning in Drosophila and Gryllus reveal a complex evolutionary history behind a model gene regulatory network. eLife 2021; 10:e68287. [PMID: 33783353 PMCID: PMC8051952 DOI: 10.7554/elife.68287] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 03/24/2021] [Indexed: 12/18/2022] Open
Abstract
Dorsoventral pattering relies on Toll and BMP signalling in all insects studied so far, with variations in the relative contributions of both pathways. Drosophila and the beetle Tribolium share extensive dependence on Toll, while representatives of more distantly related lineages like the wasp Nasonia and bug Oncopeltus rely more strongly on BMP signalling. Here, we show that in the cricket Gryllus bimaculatus, an evolutionarily distant outgroup, Toll has, like in Drosophila, a direct patterning role for the ventral half of the embryo. In addition, Toll polarises BMP signalling, although this does not involve the conserved BMP inhibitor Sog/Chordin. Finally, Toll activation relies on ovarian patterning mechanisms with striking similarity to Drosophila. Our data suggest two surprising hypotheses: (1) that Toll's patterning function in Gryllus and Drosophila is the result of convergent evolution or (2) a Drosophila-like system arose early in insect evolution and was extensively altered in multiple independent lineages.
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Affiliation(s)
- Matthias Pechmann
- Institute for Zoology/Developmental Biology, Biocenter, University of CologneKölnGermany
| | | | - Laura Pott
- Institute for Zoology/Developmental Biology, Biocenter, University of CologneKölnGermany
| | - Peter Heger
- Regional Computing Centre (RRZK), University of CologneKölnGermany
| | - Yen-Ta Chen
- Institute for Zoology/Developmental Biology, Biocenter, University of CologneKölnGermany
| | - Thomas Buchta
- Institute for Zoology/Developmental Biology, Biocenter, University of CologneKölnGermany
| | - Orhan Özüak
- Institute for Zoology/Developmental Biology, Biocenter, University of CologneKölnGermany
| | - Jeremy Lynch
- Institute for Zoology/Developmental Biology, Biocenter, University of CologneKölnGermany
- Department of Biological Sciences, University of Illinois at ChicagoChicagoUnited States
| | - Siegfried Roth
- Institute for Zoology/Developmental Biology, Biocenter, University of CologneKölnGermany
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Irizarry J, Stathopoulos A. Dynamic patterning by morphogens illuminated by cis-regulatory studies. Development 2021; 148:148/2/dev196113. [PMID: 33472851 DOI: 10.1242/dev.196113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Morphogen concentration changes in space as well as over time during development. However, how these dynamics are interpreted by cells to specify fate is not well understood. Here, we focus on two morphogens: the maternal transcription factors Bicoid and Dorsal, which directly regulate target genes to pattern Drosophila embryos. The actions of these factors at enhancers has been thoroughly dissected and provides a rich platform for understanding direct input by morphogens and their changing roles over time. Importantly, Bicoid and Dorsal do not work alone; we also discuss additional inputs that work with morphogens to control spatiotemporal gene expression in embryos.
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Affiliation(s)
- Jihyun Irizarry
- California Institute of Technology, Division of Biology and Biological Engineering, 1200 East California Blvd., Pasadena, CA 91125, USA
| | - Angelike Stathopoulos
- California Institute of Technology, Division of Biology and Biological Engineering, 1200 East California Blvd., Pasadena, CA 91125, USA
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