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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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Fenelon KD, Gao F, Borad P, Abbasi S, Pachter L, Koromila T. Cell-specific occupancy dynamics between the pioneer-like factor Opa/ZIC and Ocelliless/OTX regulate early head development in embryos. Front Cell Dev Biol 2023; 11:1126507. [PMID: 37051467 PMCID: PMC10083704 DOI: 10.3389/fcell.2023.1126507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 03/16/2023] [Indexed: 03/29/2023] Open
Abstract
During development, embryonic patterning systems direct a set of initially uncommitted pluripotent cells to differentiate into a variety of cell types and tissues. A core network of transcription factors, such as Zelda/POU5F1, Odd-paired (Opa)/ZIC3 and Ocelliless (Oc)/OTX2, are conserved across animals. While Opa is essential for a second wave of zygotic activation after Zelda, it is unclear whether Opa drives head cell specification, in the Drosophila embryo. Our hypothesis is that Opa and Oc are interacting with distinct cis-regulatory regions for shaping cell fates in the embryonic head. Super-resolution microscopy and meta-analysis of single-cell RNAseq datasets show that opa’s and oc’s overlapping expression domains are dynamic in the head region, with both factors being simultaneously transcribed at the blastula stage. Additionally, analysis of single-embryo RNAseq data reveals a subgroup of Opa-bound genes to be Opa-independent in the cellularized embryo. Interrogation of these genes against Oc ChIPseq combined with in situ data, suggests that Opa is competing with Oc for the regulation of a subgroup of genes later in gastrulation. Specifically, we find that Oc binds to late, head-specific enhancers independently and activates them in a head-specific wave of zygotic transcription, suggesting distinct roles for Oc in the blastula and gastrula stages.
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Affiliation(s)
- Kelli D. Fenelon
- Department of Biology, UT Arlington, Arlington, TX, United States
| | - Fan Gao
- Caltech Bioinformatics Resource Center (CBRC), Caltech, Pasadena, CA, United States
| | - Priyanshi Borad
- Department of Biology, UT Arlington, Arlington, TX, United States
| | - Shiva Abbasi
- Department of Biology, UT Arlington, Arlington, TX, United States
| | - Lior Pachter
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
- Department of Computational Biology and Computing and Mathematical Sciences, California Institute of Technology, Pasadena, CA, United States
| | - Theodora Koromila
- Department of Biology, UT Arlington, Arlington, TX, United States
- *Correspondence: Theodora Koromila,
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Kim YJ, Rhee K, Liu J, Jeammet S, Turner MA, Small SJ, Garcia HG. Predictive modeling reveals that higher-order cooperativity drives transcriptional repression in a synthetic developmental enhancer. eLife 2022; 11:73395. [PMID: 36503705 PMCID: PMC9836395 DOI: 10.7554/elife.73395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
A challenge in quantitative biology is to predict output patterns of gene expression from knowledge of input transcription factor patterns and from the arrangement of binding sites for these transcription factors on regulatory DNA. We tested whether widespread thermodynamic models could be used to infer parameters describing simple regulatory architectures that inform parameter-free predictions of more complex enhancers in the context of transcriptional repression by Runt in the early fruit fly embryo. By modulating the number and placement of Runt binding sites within an enhancer, and quantifying the resulting transcriptional activity using live imaging, we discovered that thermodynamic models call for higher-order cooperativity between multiple molecular players. This higher-order cooperativity captures the combinatorial complexity underlying eukaryotic transcriptional regulation and cannot be determined from simpler regulatory architectures, highlighting the challenges in reaching a predictive understanding of transcriptional regulation in eukaryotes and calling for approaches that quantitatively dissect their molecular nature.
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Affiliation(s)
- Yang Joon Kim
- Chan Zuckerberg Biohub, San Francisco, United States
| | - Kaitlin Rhee
- Department of Chemical Biology, University of California, Berkeley, Berkeley, United States
| | - Jonathan Liu
- Department of Physics, University of California, Berkeley, Berkeley, United States
| | - Selene Jeammet
- Department of Biology, Ecole Polytechnique, Paris, France
| | - Meghan A Turner
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States
| | - Stephen J Small
- Department of Biology, New York University, New York, United States
| | - Hernan G Garcia
- Chan Zuckerberg Biohub, San Francisco, United States.,Department of Physics, University of California, Berkeley, Berkeley, United States.,Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Institute for Quantitative Biosciences-QB3, University of California at Berkeley, Berkeley, United States
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Hoppe C, Ashe HL. Live imaging and quantitation of nascent transcription using the MS2/MCP system in the Drosophila embryo. STAR Protoc 2021; 2:100379. [PMID: 33778778 PMCID: PMC7982776 DOI: 10.1016/j.xpro.2021.100379] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Visualizing transcription live in Drosophila is providing important new insights into the spatiotemporal regulation of transcription. Here, we describe a protocol to visualize and quantitate transcription from gene loci that are tagged with MS2 stem-loop sequences in the Drosophila embryo. MS2 stem-loop sequences are recognized by a coat protein fused to a fluorescent protein and visualized with microscopy. We also describe an analysis pipeline to extract and subsequently quantify transcription dynamics. For complete details on the use and execution of this protocol, please refer to Hoppe et al. (2020).
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Affiliation(s)
- Caroline Hoppe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Hilary L. Ashe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
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Koromila T, Gao F, Iwasaki Y, He P, Pachter L, Gergen JP, Stathopoulos A. Odd-paired is a pioneer-like factor that coordinates with Zelda to control gene expression in embryos. eLife 2020; 9:e59610. [PMID: 32701060 PMCID: PMC7417190 DOI: 10.7554/elife.59610] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 07/22/2020] [Indexed: 01/29/2023] Open
Abstract
Pioneer factors such as Zelda (Zld) help initiate zygotic transcription in Drosophila early embryos, but whether other factors support this dynamic process is unclear. Odd-paired (Opa), a zinc-finger transcription factor expressed at cellularization, controls the transition of genes from pair-rule to segmental patterns along the anterior-posterior axis. Finding that Opa also regulates expression through enhancer sog_Distal along the dorso-ventral axis, we hypothesized Opa's role is more general. Chromatin-immunoprecipitation (ChIP-seq) confirmed its in vivo binding to sog_Distal but also identified widespread binding throughout the genome, comparable to Zld. Furthermore, chromatin assays (ATAC-seq) demonstrate that Opa, like Zld, influences chromatin accessibility genome-wide at cellularization, suggesting both are pioneer factors with common as well as distinct targets. Lastly, embryos lacking opa exhibit widespread, late patterning defects spanning both axes. Collectively, these data suggest Opa is a general timing factor and likely late-acting pioneer factor that drives a secondary wave of zygotic gene expression.
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Affiliation(s)
- Theodora Koromila
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - Fan Gao
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - Yasuno Iwasaki
- Stony Brook University, Department of Biochemistry and Cell Biology and Center for Developmental GeneticsStony BrookUnited States
| | - Peng He
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - Lior Pachter
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - J Peter Gergen
- Stony Brook University, Department of Biochemistry and Cell Biology and Center for Developmental GeneticsStony BrookUnited States
| | - Angelike Stathopoulos
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
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Abstract
Drosophila melanogaster embryos develop initially as a syncytium of totipotent nuclei and subsequently, once cellularized, undergo morphogenetic movements associated with gastrulation to generate the three somatic germ layers of the embryo: mesoderm, ectoderm, and endoderm. In this chapter, we focus on the first phase of gastrulation in Drosophila involving patterning of early embryos when cells differentiate their gene expression programs. This patterning process requires coordination of multiple developmental processes including genome reprogramming at the maternal-to-zygotic transition, combinatorial action of transcription factors to support distinct gene expression, and dynamic feedback between this genetic patterning by transcription factors and changes in cell morphology. We discuss the gene regulatory programs acting during patterning to specify the three germ layers, which involve the regulation of spatiotemporal gene expression coupled to physical tissue morphogenesis.
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Affiliation(s)
- Angelike Stathopoulos
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, United States.
| | - Susan Newcomb
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, United States
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