1
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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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Pollex T, Marco-Ferreres R, Ciglar L, Ghavi-Helm Y, Rabinowitz A, Viales RR, Schaub C, Jankowski A, Girardot C, Furlong EEM. Chromatin gene-gene loops support the cross-regulation of genes with related function. Mol Cell 2024; 84:822-838.e8. [PMID: 38157845 DOI: 10.1016/j.molcel.2023.12.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/31/2023] [Accepted: 12/14/2023] [Indexed: 01/03/2024]
Abstract
Chromatin loops between gene pairs have been observed in diverse contexts in both flies and vertebrates. Combining high-resolution Capture-C, DNA fluorescence in situ hybridization, and genetic perturbations, we dissect the functional role of three loops between genes with related function during Drosophila embryogenesis. By mutating the loop anchor (but not the gene) or the gene (but not loop anchor), we disentangle loop formation and gene expression and show that the 3D proximity of paralogous gene loci supports their co-regulation. Breaking the loop leads to either an attenuation or enhancement of expression and perturbs their relative levels of expression and cross-regulation. Although many loops appear constitutive across embryogenesis, their function can change in different developmental contexts. Taken together, our results indicate that chromatin gene-gene loops act as architectural scaffolds that can be used in different ways in different contexts to fine-tune the coordinated expression of genes with related functions and sustain their cross-regulation.
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Affiliation(s)
- Tim Pollex
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Raquel Marco-Ferreres
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Lucia Ciglar
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Yad Ghavi-Helm
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Adam Rabinowitz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | | | - Christoph Schaub
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Aleksander Jankowski
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Charles Girardot
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Eileen E M Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany.
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3
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Fenelon KD, Krause J, Koromila T. Opticool: Cutting-edge transgenic optical tools. PLoS Genet 2024; 20:e1011208. [PMID: 38517915 PMCID: PMC10959397 DOI: 10.1371/journal.pgen.1011208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024] Open
Abstract
Only a few short decades have passed since the sequencing of GFP, yet the modern repertoire of transgenically encoded optical tools implies an exponential proliferation of ever improving constructions to interrogate the subcellular environment. A myriad of tags for labeling proteins, RNA, or DNA have arisen in the last few decades, facilitating unprecedented visualization of subcellular components and processes. Development of a broad array of modern genetically encoded sensors allows real-time, in vivo detection of molecule levels, pH, forces, enzyme activity, and other subcellular and extracellular phenomena in ever expanding contexts. Optogenetic, genetically encoded optically controlled manipulation systems have gained traction in the biological research community and facilitate single-cell, real-time modulation of protein function in vivo in ever broadening, novel applications. While this field continues to explosively expand, references are needed to assist scientists seeking to use and improve these transgenic devices in new and exciting ways to interrogate development and disease. In this review, we endeavor to highlight the state and trajectory of the field of in vivo transgenic optical tools.
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Affiliation(s)
- Kelli D. Fenelon
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Julia Krause
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Theodora Koromila
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
- School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
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4
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Meyer K, Lammers NC, Bugaj LJ, Garcia HG, Weiner OD. Optogenetic control of YAP reveals a dynamic communication code for stem cell fate and proliferation. Nat Commun 2023; 14:6929. [PMID: 37903793 PMCID: PMC10616176 DOI: 10.1038/s41467-023-42643-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 10/17/2023] [Indexed: 11/01/2023] Open
Abstract
YAP is a transcriptional regulator that controls pluripotency, cell fate, and proliferation. How cells ensure the selective activation of YAP effector genes is unknown. This knowledge is essential to rationally control cellular decision-making. Here we leverage optogenetics, live-imaging of transcription, and cell fate analysis to understand and control gene activation and cell behavior. We reveal that cells decode the steady-state concentrations and timing of YAP activation to control proliferation, cell fate, and expression of the pluripotency regulators Oct4 and Nanog. While oscillatory YAP inputs induce Oct4 expression and proliferation optimally at frequencies that mimic native dynamics, cellular differentiation requires persistently low YAP levels. We identify the molecular logic of the Oct4 dynamic decoder, which acts through an adaptive change sensor. Our work reveals how YAP levels and dynamics enable multiplexing of information transmission for the regulation of developmental decision-making and establishes a platform for the rational control of these behaviors.
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Affiliation(s)
- Kirstin Meyer
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Nicholas C Lammers
- Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Lukasz J Bugaj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Hernan G Garcia
- Biophysics Graduate Group, University of California at Berkeley, Berkeley, CA, USA
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
- Institute for Quantitative Biosciences-QB3, University of California at Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Orion D Weiner
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
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5
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Harrison MM, Marsh AJ, Rushlow CA. Setting the stage for development: the maternal-to-zygotic transition in Drosophila. Genetics 2023; 225:iyad142. [PMID: 37616526 PMCID: PMC10550319 DOI: 10.1093/genetics/iyad142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/18/2023] [Indexed: 08/26/2023] Open
Abstract
The zygote has a daunting task ahead of itself; it must develop from a single cell (fertilized egg) into a fully functioning adult with a multitude of different cell types. In the beginning, the zygote has help from its mother, in the form of gene products deposited into the egg, but eventually, it must rely on its own resources to proceed through development. The transfer of developmental control from the mother to the embryo is called the maternal-to-zygotic transition (MZT). All animals undergo this transition, which is defined by two main processes-the degradation of maternal RNAs and the synthesis of new RNAs from the zygote's own genome. Here, we review the regulation of the MZT in Drosophila, but given the broad conservation of this essential process, much of the regulation is shared among metazoans.
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Affiliation(s)
- Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706USA
| | - Audrey J Marsh
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706USA
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6
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Arnosti DN. Soft repression and chromatin modification by conserved transcriptional corepressors. Enzymes 2023; 53:69-96. [PMID: 37748837 DOI: 10.1016/bs.enz.2023.08.001] [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: 09/27/2023]
Abstract
Transcriptional regulation in eukaryotic cells involves the activity of multifarious DNA-binding transcription factors and recruited corepressor complexes. Together, these complexes interact with the core transcriptional machinery, chromatin, and nuclear environment to effect complex patterns of gene regulation. Much focus has been paid to the action of master regulatory switches that are key to developmental and environmental responses, as these genetic elements have important phenotypic effects. The regulation of widely-expressed metabolic control genes has been less well studied, particularly in cases in which physically-interacting repressors and corepressors have subtle influences on steady-state expression. This latter phenomenon, termed "soft repression" is a topic of increasing interest as genomic approaches provide ever more powerful tools to uncover the significance of this level of control. This review provides an oversight of classic and current approaches to the study of transcriptional repression in eukaryotic systems, with a specific focus on opportunities and challenges that lie ahead in the study of soft repression.
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Affiliation(s)
- David N Arnosti
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States.
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7
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Han D, Churcher S, Nordman JT. PCR cloning Intermediated Gibson assembly (PIG) for Constructing DNA Repair Templates in CRISPR-Cas9 Based Gene Editing. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000916. [PMID: 37662052 PMCID: PMC10474481 DOI: 10.17912/micropub.biology.000916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/14/2023] [Accepted: 08/16/2023] [Indexed: 09/05/2023]
Abstract
The CRISPR-Cas9 gene-editing system has revolutionized genome engineering, allowing precise modifications to be made in a wide range of organisms. One significant challenge associated with CRISPR-Cas9 mediated gene editing is the construction of DNA repair templates containing homology arms, a screenable marker and a tag sequence of interest. Here, we present an efficient, two-step strategy to generate DNA repair templates in approximately one week, facilitating rapid and precise genome engineering applications.
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Affiliation(s)
- Dongsheng Han
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States
| | - Scott Churcher
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States
| | - Jared T. Nordman
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States
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8
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Nagasawa Y, Ueda HH, Kawabata H, Murakoshi H. LOV2-based photoactivatable CaMKII and its application to single synapses: Local Optogenetics. Biophys Physicobiol 2023; 20:e200027. [PMID: 38496236 PMCID: PMC10941968 DOI: 10.2142/biophysico.bppb-v20.0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/02/2023] [Indexed: 03/19/2024] Open
Abstract
Optogenetic techniques offer a high spatiotemporal resolution to manipulate cellular activity. For instance, Channelrhodopsin-2 with global light illumination is the most widely used to control neuronal activity at the cellular level. However, the cellular scale is much larger than the diffraction limit of light (<1 μm) and does not fully exploit the features of the "high spatial resolution" of optogenetics. For instance, until recently, there were no optogenetic methods to induce synaptic plasticity at the level of single synapses. To address this, we developed an optogenetic tool named photoactivatable CaMKII (paCaMKII) by fusing a light-sensitive domain (LOV2) to CaMKIIα, which is a protein abundantly expressed in neurons of the cerebrum and hippocampus and essential for synaptic plasticity. Combining photoactivatable CaMKII with two-photon excitation, we successfully activated it in single spines, inducing synaptic plasticity (long-term potentiation) in hippocampal neurons. We refer to this method as "Local Optogenetics", which involves the local activation of molecules and measurement of cellular responses. In this review, we will discuss the characteristics of LOV2, the recent development of its derivatives, and the development and application of paCaMKII.
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Affiliation(s)
- Yutaro Nagasawa
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Hiromi H Ueda
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Haruka Kawabata
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Hideji Murakoshi
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
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9
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Zhu L, McNamara HM, Toettcher JE. Light-switchable transcription factors obtained by direct screening in mammalian cells. Nat Commun 2023; 14:3185. [PMID: 37268649 DOI: 10.1038/s41467-023-38993-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/24/2023] [Indexed: 06/04/2023] Open
Abstract
Optogenetic tools can provide fine spatial and temporal control over many biological processes. Yet the development of new light-switchable protein variants remains challenging, and the field still lacks general approaches to engineering or discovering protein variants with light-switchable biological functions. Here, we adapt strategies for protein domain insertion and mammalian-cell expression to generate and screen a library of candidate optogenetic tools directly in mammalian cells. The approach is based on insertion of the AsLOV2 photoswitchable domain at all possible positions in a candidate protein of interest, introduction of the library into mammalian cells, and light/dark selection for variants with photoswitchable activity. We demonstrate the approach's utility using the Gal4-VP64 transcription factor as a model system. Our resulting LightsOut transcription factor exhibits a > 150-fold change in transcriptional activity between dark and blue light conditions. We show that light-switchable function generalizes to analogous insertion sites in two additional Cys6Zn2 and C2H2 zinc finger domains, providing a starting point for optogenetic regulation of a broad class of transcription factors. Our approach can streamline the identification of single-protein optogenetic switches, particularly in cases where structural or biochemical knowledge is limited.
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Affiliation(s)
- Liyuan Zhu
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Harold M McNamara
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
- Lewis Sigler Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA.
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10
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McNamara HM, Ramm B, Toettcher JE. Synthetic developmental biology: New tools to deconstruct and rebuild developmental systems. Semin Cell Dev Biol 2023; 141:33-42. [PMID: 35484026 PMCID: PMC10332110 DOI: 10.1016/j.semcdb.2022.04.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/13/2022] [Indexed: 11/16/2022]
Abstract
Technological advances have driven many recent advances in developmental biology. Light sheet imaging can reveal single-cell dynamics in living three-dimensional tissues, whereas single-cell genomic methods open the door to a complete catalogue of cell types and gene expression states. An equally powerful but complementary set of approaches are also becoming available to define development processes from the bottom up. These synthetic approaches aim to reconstruct the minimal developmental patterns, signaling processes, and gene networks that produce the basic set of developmental operations: spatial polarization, morphogen interpretation, tissue movement, and cellular memory. In this review we discuss recent approaches at the intersection of synthetic biology and development, including synthetic circuits to deliver and record signaling stimuli and synthetic reconstitution of pattern formation on multicellular scales.
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Affiliation(s)
- Harold M McNamara
- Lewis Sigler Institute, Princeton University, Princeton, NJ 08544, USA; Department of Physics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Beatrice Ramm
- Department of Physics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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11
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Lan TH, He L, Huang Y, Zhou Y. Optogenetics for transcriptional programming and genetic engineering. Trends Genet 2022; 38:1253-1270. [PMID: 35738948 PMCID: PMC10484296 DOI: 10.1016/j.tig.2022.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 01/24/2023]
Abstract
Optogenetics combines genetics and biophotonics to enable noninvasive control of biological processes with high spatiotemporal precision. When engineered into protein machineries that govern the cellular information flow as depicted in the central dogma, multiple genetically encoded non-opsin photosensory modules have been harnessed to modulate gene transcription, DNA or RNA modifications, DNA recombination, and genome engineering by utilizing photons emitting in the wide range of 200-1000 nm. We present herein generally applicable modular strategies for optogenetic engineering and highlight latest advances in the broad applications of opsin-free optogenetics to program transcriptional outputs and precisely manipulate the mammalian genome, epigenome, and epitranscriptome. We also discuss current challenges and future trends in opsin-free optogenetics, which has been rapidly evolving to meet the growing needs in synthetic biology and genetics research.
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Affiliation(s)
- Tien-Hung Lan
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA
| | - Lian He
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA.
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA; Department of Translational Medical Sciences, School of Medicine, Texas A&M University, Houston, TX 77030, USA.
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12
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Forlani G, Antwi EB, Weis D, Öztürk MA, Queck BA, Brecht D, Di Ventura B. Analysis of Slow-Cycling Variants of the Light-Inducible Nuclear Protein Export System LEXY in Mammalian Cells. ACS Synth Biol 2022; 11:3529-3533. [PMID: 36180042 PMCID: PMC9594308 DOI: 10.1021/acssynbio.2c00232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The optogenetic tool LEXY consists of the second light oxygen voltage (LOV) domain of Avena sativa phototropin 1 mutated to contain a nuclear export signal. It allows exporting from the nucleus with blue light proteins of interest (POIs) genetically fused to it. Mutations slowing the dark recovery rate of the LOV domain within LEXY were recently shown to allow for better depletion of some POIs from the nucleus in Drosophila embryos and for the usage of low light illumination regimes. We investigated these variants in mammalian cells and found they increase the cytoplasmic localization of the proteins we tested after illumination, but also during the dark phases, which corresponds to higher leakiness of the system. These data suggest that, when aiming to sequester into the nucleus a protein with a cytoplasmic function, the original LEXY is preferable. The iLEXY variants are, instead, advantageous when wanting to deplete the nucleus of the POI as much as possible.
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Affiliation(s)
- Giada Forlani
- Centers
for Biological Signalling Studies BIOSS and CIBSS, Albert Ludwigs University of Freiburg, Freiburg, 79104, Germany,Faculty
of Biology, Institute of Biology II, Albert
Ludwigs University of Freiburg, Freiburg, 79104, Germany,Spemann
Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University of Freiburg, Freiburg, 79104, Germany
| | - Enoch B. Antwi
- Centers
for Biological Signalling Studies BIOSS and CIBSS, Albert Ludwigs University of Freiburg, Freiburg, 79104, Germany,Faculty
of Biology, Institute of Biology II, Albert
Ludwigs University of Freiburg, Freiburg, 79104, Germany,E-mail:
| | - Daniel Weis
- Faculty
of Biology, Institute of Biology II, Albert
Ludwigs University of Freiburg, Freiburg, 79104, Germany
| | - Mehmet A. Öztürk
- Centers
for Biological Signalling Studies BIOSS and CIBSS, Albert Ludwigs University of Freiburg, Freiburg, 79104, Germany,Faculty
of Biology, Institute of Biology II, Albert
Ludwigs University of Freiburg, Freiburg, 79104, Germany
| | - Bastian A.W. Queck
- Faculty
of Biology, Institute of Biology II, Albert
Ludwigs University of Freiburg, Freiburg, 79104, Germany,Department
of Bio- and Environmental Sciences, International Institute Zittau, Technische Universität Dresden, Zittau, 01069, Germany
| | - Dominik Brecht
- Faculty
of Biology, Institute of Biology II, Albert
Ludwigs University of Freiburg, Freiburg, 79104, Germany
| | - Barbara Di Ventura
- Centers
for Biological Signalling Studies BIOSS and CIBSS, Albert Ludwigs University of Freiburg, Freiburg, 79104, Germany,Faculty
of Biology, Institute of Biology II, Albert
Ludwigs University of Freiburg, Freiburg, 79104, Germany,E-mail:
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13
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McCue AC, Kuhlman B. Design and engineering of light-sensitive protein switches. Curr Opin Struct Biol 2022; 74:102377. [PMID: 35461160 PMCID: PMC9968517 DOI: 10.1016/j.sbi.2022.102377] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 11/03/2022]
Abstract
Engineered, light-sensitive protein switches are used to interrogate a broad variety of biological processes. These switches are typically constructed by genetically fusing naturally occurring light-responsive protein domains with functional domains from other proteins. Protein activity can be controlled using a variety of mechanisms including light-induced colocalization, caging, and allosteric regulation. Protein design efforts have focused on reducing background signaling, maximizing the change in activity upon light stimulation, and perturbing the kinetics of switching. It is common to combine structure-based modeling with experimental screening to identify ideal fusion points between domains and discover point mutations that optimize switching. Here, we introduce commonly used light-sensitive domains and summarize recent progress in using them to regulate protein activity.
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Affiliation(s)
- Amelia C McCue
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27514, USA.
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14
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Singh AP, Wu P, Ryabichko S, Raimundo J, Swan M, Wieschaus E, Gregor T, Toettcher JE. Optogenetic control of the Bicoid morphogen reveals fast and slow modes of gap gene regulation. Cell Rep 2022; 38:110543. [PMID: 35320726 PMCID: PMC9019726 DOI: 10.1016/j.celrep.2022.110543] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/10/2022] [Accepted: 02/28/2022] [Indexed: 11/29/2022] Open
Abstract
Developmental patterning networks are regulated by multiple inputs and feedback connections that rapidly reshape gene expression, limiting the information that can be gained solely from slow genetic perturbations. Here we show that fast optogenetic stimuli, real-time transcriptional reporters, and a simplified genetic background can be combined to reveal the kinetics of gene expression downstream of a developmental transcription factor in vivo. We engineer light-controlled versions of the Bicoid transcription factor and study their effects on downstream gap genes in embryos. Our results recapitulate known relationships, including rapid Bicoid-dependent transcription of giant and hunchback and delayed repression of Krüppel. In addition, we find that the posterior pattern of knirps exhibits a quick but inverted response to Bicoid perturbation, suggesting a noncanonical role for Bicoid in directly suppressing knirps transcription. Acute modulation of transcription factor concentration while recording output gene activity represents a powerful approach for studying developmental gene networks in vivo.
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Affiliation(s)
- Anand P Singh
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Ping Wu
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sergey Ryabichko
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - João Raimundo
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Michael Swan
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Eric Wieschaus
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Thomas Gregor
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Physics, Princeton University, Princeton, NJ 08544, USA.
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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15
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Secchia S, Forneris M, Heinen T, Stegle O, Furlong EEM. Simultaneous cellular and molecular phenotyping of embryonic mutants using single-cell regulatory trajectories. Dev Cell 2022; 57:496-511.e8. [PMID: 35176234 PMCID: PMC8893321 DOI: 10.1016/j.devcel.2022.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/04/2021] [Accepted: 01/26/2022] [Indexed: 11/09/2022]
Abstract
Developmental progression and cellular diversity are largely driven by transcription factors (TFs); yet, characterizing their loss-of-function phenotypes remains challenging and often disconnected from their underlying molecular mechanisms. Here, we combine single-cell regulatory genomics with loss-of-function mutants to jointly assess both cellular and molecular phenotypes. Performing sci-ATAC-seq at eight overlapping time points during Drosophila mesoderm development could reconstruct the developmental trajectories of all major muscle types and reveal the TFs and enhancers involved. To systematically assess mutant phenotypes, we developed a single-nucleus genotyping strategy to process embryo pools of mixed genotypes. Applying this to four TF mutants could identify and quantify their characterized phenotypes de novo and discover new ones, while simultaneously revealing their regulatory input and mode of action. Our approach is a general framework to dissect the functional input of TFs in a systematic, unbiased manner, identifying both cellular and molecular phenotypes at a scale and resolution that has not been feasible before. scATAC time course constructs regulatory trajectories of Drosophila muscle lineages Combining a wild-type trajectory with mutants identifies and quantifies phenotypes de novo Digital nuclear genotyping enables the processing of pooled embryos of mixed genotypes This framework simultaneously uncovers cellular and molecular phenotypes in embryos
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Affiliation(s)
- Stefano Secchia
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Baden-Württemberg, Germany
| | - Mattia Forneris
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany
| | - Tobias Heinen
- Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Baden-Württemberg, Germany; Heidelberg University, Faculty of Mathematics and Computer Science, 69120 Heidelberg, Baden-Württemberg, Germany
| | - Oliver Stegle
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany; Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Baden-Württemberg, Germany
| | - Eileen E M Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany.
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Farahani PE, Nelson CM. Revealing epithelial morphogenetic mechanisms through live imaging. Curr Opin Genet Dev 2022; 72:61-68. [PMID: 34864332 PMCID: PMC8860867 DOI: 10.1016/j.gde.2021.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/08/2021] [Accepted: 10/20/2021] [Indexed: 02/03/2023]
Abstract
Epithelial morphogenesis is guided by mechanical forces and biochemical signals that vary spatiotemporally. As many morphogenetic events are driven by rapid cellular processes, understanding morphogenesis requires monitoring development in real time. Here, we discuss how live-imaging approaches can help identify morphogenetic mechanisms otherwise missed in static snapshots of development. We begin with a summary of live-imaging strategies, including recent advances that push the limits of spatiotemporal resolution and specimen size. We then describe recent efforts that employ live imaging to uncover morphogenetic mechanisms. We conclude by discussing how information collected from live imaging can be enhanced by genetically encoded biosensors and spatiotemporal perturbation techniques to determine the dynamics of patterning of developmental signals and their importance for guiding morphogenesis.
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Affiliation(s)
- Payam E Farahani
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, United States
| | - Celeste M Nelson
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, United States; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States.
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