1
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Xu C, Li Z, Lyu C, Hu Y, McLaughlin CN, Wong KKL, Xie Q, Luginbuhl DJ, Li H, Udeshi ND, Svinkina T, Mani DR, Han S, Li T, Li Y, Guajardo R, Ting AY, Carr SA, Li J, Luo L. Molecular and cellular mechanisms of teneurin signaling in synaptic partner matching. Cell 2024; 187:5081-5101.e19. [PMID: 38996528 DOI: 10.1016/j.cell.2024.06.022] [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] [Received: 02/11/2024] [Revised: 05/20/2024] [Accepted: 06/18/2024] [Indexed: 07/14/2024]
Abstract
In developing brains, axons exhibit remarkable precision in selecting synaptic partners among many non-partner cells. Evolutionarily conserved teneurins are transmembrane proteins that instruct synaptic partner matching. However, how intracellular signaling pathways execute teneurins' functions is unclear. Here, we use in situ proximity labeling to obtain the intracellular interactome of a teneurin (Ten-m) in the Drosophila brain. Genetic interaction studies using quantitative partner matching assays in both olfactory receptor neurons (ORNs) and projection neurons (PNs) reveal a common pathway: Ten-m binds to and negatively regulates a RhoGAP, thus activating the Rac1 small GTPases to promote synaptic partner matching. Developmental analyses with single-axon resolution identify the cellular mechanism of synaptic partner matching: Ten-m signaling promotes local F-actin levels and stabilizes ORN axon branches that contact partner PN dendrites. Combining spatial proteomics and high-resolution phenotypic analyses, this study advanced our understanding of both cellular and molecular mechanisms of synaptic partner matching.
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Affiliation(s)
- Chuanyun Xu
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Zhuoran Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Cheng Lyu
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Yixin Hu
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Colleen N McLaughlin
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Kenneth Kin Lam Wong
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Qijing Xie
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Neurosciences Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - David J Luginbuhl
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Hongjie Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Namrata D Udeshi
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Tanya Svinkina
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - D R Mani
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Shuo Han
- Departments of Genetics, Biology, and Chemistry, Chan Zuckerberg Biohub, Stanford University, Stanford, CA 94305, USA
| | - Tongchao Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Yang Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Ricardo Guajardo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Alice Y Ting
- Departments of Genetics, Biology, and Chemistry, Chan Zuckerberg Biohub, Stanford University, Stanford, CA 94305, USA
| | - Steven A Carr
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jiefu Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
| | - Liqun Luo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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2
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Zhang Y, Zeng J, Xu B. Phenotypic analysis with trans-recombination-based genetic mosaic models. J Biol Chem 2023; 299:105265. [PMID: 37734556 PMCID: PMC10587715 DOI: 10.1016/j.jbc.2023.105265] [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] [Received: 07/18/2023] [Revised: 09/01/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023] Open
Abstract
Mosaicism refers to the presence of genetically distinct cell populations in an individual derived from a single zygote, which occurs during the process of development, aging, and genetic diseases. To date, a variety of genetically engineered mosaic analysis models have been established and widely used in studying gene function at exceptional cellular and spatiotemporal resolution, leading to many ground-breaking discoveries. Mosaic analysis with a repressible cellular marker and mosaic analysis with double markers are genetic mosaic analysis models based on trans-recombination. These models can generate sibling cells of distinct genotypes in the same animal and simultaneously label them with different colors. As a result, they offer a powerful approach for lineage tracing and studying the behavior of individual mutant cells in a wildtype environment, which is particularly useful for determining whether gene function is cell autonomous or nonautonomous. Here, we present a comprehensive review on the establishment and applications of mosaic analysis with a repressible cellular marker and mosaic analysis with double marker systems. Leveraging the capabilities of these mosaic models for phenotypic analysis will facilitate new discoveries on the cellular and molecular mechanisms of development and disease.
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Affiliation(s)
- Yu Zhang
- School of Life Sciences, Nantong University, Nantong, Jiangsu, China
| | - Jianhao Zeng
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Bing Xu
- School of Life Sciences, Nantong University, Nantong, Jiangsu, China.
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3
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Santos-França PL, David LA, Kassem F, Meng XQ, Cayouette M. Time to see: How temporal identity factors specify the developing mammalian retina. Semin Cell Dev Biol 2023; 142:36-42. [PMID: 35760728 DOI: 10.1016/j.semcdb.2022.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022]
Abstract
Understanding how retinal progenitor cells (RPCs) give rise to the variety of neural cell types of the retina has been a question of major interest over the last few decades. While environmental cues and transcription factor networks have been shown to control specific cell fate decisions, how RPCs alter fate output over time to control proper histogenesis remains poorly understood. In recent years, the identification of "temporal identity factors (TIFs)", which control RPC competence states to ensure that the right cell types are produced at the right time, has contributed to increasing our understanding of temporal patterning in the retina. Here, we review the different TIFs identified to date in the mammalian retina and discuss the underlying mechanisms by which they are thought to operate. We conclude by speculating on how identification of temporal patterning mechanisms might support the development of new therapeutic approaches against visual impairments.
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Affiliation(s)
- Pedro L Santos-França
- Cellular Neurobiology Research Unit, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada; Molecular Biology Program, Université de Montréal, Montréal, QC, Canada
| | - Luke Ajay David
- Cellular Neurobiology Research Unit, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada; Integrated Program in Neuroscience, Faculty of Medicine, McGill University, Montréal, QC, Canada
| | - Fatima Kassem
- Cellular Neurobiology Research Unit, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada; Integrated Program in Neuroscience, Faculty of Medicine, McGill University, Montréal, QC, Canada
| | - Xiang Qi Meng
- Integrated Program in Neuroscience, Faculty of Medicine, McGill University, Montréal, QC, Canada
| | - Michel Cayouette
- Cellular Neurobiology Research Unit, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, Canada; Molecular Biology Program, Université de Montréal, Montréal, QC, Canada; Integrated Program in Neuroscience, Faculty of Medicine, McGill University, Montréal, QC, Canada; Department of Medicine, Université de Montréal, QC, Canada; Department of Anatomy and Cell Biology and Division of Experimental Medicine, McGill University, Montreal, QC, Canada.
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4
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Yamauchi Y, Matsukura H, Motone K, Ueda M, Aoki W. Evaluation of a library of loxP variants with a wide range of recombination efficiencies by Cre. PLoS One 2022; 17:e0276657. [PMID: 36269789 PMCID: PMC9586403 DOI: 10.1371/journal.pone.0276657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/11/2022] [Indexed: 11/18/2022] Open
Abstract
Sparse labeling of individual cells is an important approach in neuroscience and many other fields of research. Various methods have been developed to sparsely label only a small population of cells; however, there is no simple and reproducible strategy for managing the probability of sparse labeling at desired levels. Here, we aimed to develop a novel methodology based on the Cre-lox system to regulate sparseness at desired levels, and we purely analyzed cleavage efficiencies of loxP mutants by Cre. We hypothesized that mutations in the loxP sequence reduce the recognition efficiency by Cre, which enables the regulation of the sparseness level of gene expression. In this research, we mutagenized the loxP sequence and analyzed a library of loxP variants. We evaluated more than 1000 mutant loxP sequences, including mutants with reduced excision efficiencies by Cre ranging from 0.51% to 59%. This result suggests that these mutant loxP sequences can be useful in regulating the sparseness of genetic labeling at desired levels.
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Affiliation(s)
- Yuji Yamauchi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
- Japan Society for the Promotion of Science, Sakyo-ku, Kyoto, Japan
| | - Hidenori Matsukura
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Keisuke Motone
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, Washington, United States of America
| | - Mitsuyoshi Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Wataru Aoki
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
- * E-mail:
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5
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Contreras X, Amberg N, Davaatseren A, Hansen AH, Sonntag J, Andersen L, Bernthaler T, Streicher C, Heger A, Johnson RL, Schwarz LA, Luo L, Rülicke T, Hippenmeyer S. A genome-wide library of MADM mice for single-cell genetic mosaic analysis. Cell Rep 2021; 35:109274. [PMID: 34161767 PMCID: PMC8317686 DOI: 10.1016/j.celrep.2021.109274] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 04/14/2021] [Accepted: 05/28/2021] [Indexed: 10/21/2022] Open
Abstract
Mosaic analysis with double markers (MADM) offers one approach to visualize and concomitantly manipulate genetically defined cells in mice with single-cell resolution. MADM applications include the analysis of lineage, single-cell morphology and physiology, genomic imprinting phenotypes, and dissection of cell-autonomous gene functions in vivo in health and disease. Yet, MADM can only be applied to <25% of all mouse genes on select chromosomes to date. To overcome this limitation, we generate transgenic mice with knocked-in MADM cassettes near the centromeres of all 19 autosomes and validate their use across organs. With this resource, >96% of the entire mouse genome can now be subjected to single-cell genetic mosaic analysis. Beyond a proof of principle, we apply our MADM library to systematically trace sister chromatid segregation in distinct mitotic cell lineages. We find striking chromosome-specific biases in segregation patterns, reflecting a putative mechanism for the asymmetric segregation of genetic determinants in somatic stem cell division.
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Affiliation(s)
- Ximena Contreras
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Nicole Amberg
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | | | - Andi H Hansen
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Johanna Sonntag
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Lill Andersen
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Tina Bernthaler
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Carmen Streicher
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Anna Heger
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Randy L Johnson
- Department of Biochemistry and Molecular Biology, University of Texas, Houston, TX 77030, USA
| | - Lindsay A Schwarz
- HHMI and Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Liqun Luo
- HHMI and Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Thomas Rülicke
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Simon Hippenmeyer
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
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6
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Veldman MB, Park CS, Eyermann CM, Zhang JY, Zuniga-Sanchez E, Hirano AA, Daigle TL, Foster NN, Zhu M, Langfelder P, Lopez IA, Brecha NC, Zipursky SL, Zeng H, Dong HW, Yang XW. Brainwide Genetic Sparse Cell Labeling to Illuminate the Morphology of Neurons and Glia with Cre-Dependent MORF Mice. Neuron 2020; 108:111-127.e6. [PMID: 32795398 PMCID: PMC7572760 DOI: 10.1016/j.neuron.2020.07.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/01/2020] [Accepted: 07/15/2020] [Indexed: 12/27/2022]
Abstract
Cajal recognized that the elaborate shape of neurons is fundamental to their function in the brain. However, there are no simple and generalizable genetic methods to study neuronal or glial cell morphology in the mammalian brain. Here, we describe four mouse lines conferring Cre-dependent sparse cell labeling based on mononucleotide repeat frameshift (MORF) as a stochastic translational switch. Notably, the optimized MORF3 mice, with a membrane-bound multivalent immunoreporter, confer Cre-dependent sparse and bright labeling of thousands of neurons, astrocytes, or microglia in each brain, revealing their intricate morphologies. MORF3 mice are compatible with imaging in tissue-cleared thick brain sections and with immuno-EM. An analysis of 151 MORF3-labeled developing retinal horizontal cells reveals novel morphological cell clusters and axonal maturation patterns. Our study demonstrates a conceptually novel, simple, generalizable, and scalable mouse genetic solution to sparsely label and illuminate the morphology of genetically defined neurons and glia in the mammalian brain.
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Affiliation(s)
- Matthew B Veldman
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, and Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Chang Sin Park
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, and Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Charles M Eyermann
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, and Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jason Y Zhang
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, and Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elizabeth Zuniga-Sanchez
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Arlene A Hirano
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Veterans Administration of Greater Los Angeles Health System, Los Angeles, CA 90073, USA
| | - Tanya L Daigle
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Nicholas N Foster
- Center for Integrative Connectomics, University of Southern California Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, USC, Los Angeles, CA, 90033, USA
| | - Muye Zhu
- Center for Integrative Connectomics, University of Southern California Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, USC, Los Angeles, CA, 90033, USA
| | - Peter Langfelder
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, and Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ivan A Lopez
- Cellular and Molecular Biology of the Inner Ear Laboratory, Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Nicholas C Brecha
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Veterans Administration of Greater Los Angeles Health System, Los Angeles, CA 90073, USA; Departments of Medicine and Ophthalmology, Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Hong-Wei Dong
- Center for Integrative Connectomics, University of Southern California Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, USC, Los Angeles, CA, 90033, USA; Zilkha Neurogenetic Institute, and Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - X William Yang
- Center for Neurobehavioral Genetics, Jane and Terry Semel Institute for Neuroscience and Human Behavior, and Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA.
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7
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RecV recombinase system for in vivo targeted optogenomic modifications of single cells or cell populations. Nat Methods 2020; 17:422-429. [PMID: 32203389 PMCID: PMC7135964 DOI: 10.1038/s41592-020-0774-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 02/11/2020] [Indexed: 11/11/2022]
Abstract
Brain circuits comprise vast numbers of intricately interconnected neurons with diverse molecular, anatomical and physiological properties. To allow “user-defined” targeting of individual neurons for structural and functional studies, we created light-inducible site-specific DNA recombinases (SSRs) based on Cre, Dre and Flp (RecVs). RecVs can induce genomic modifications by one-photon or two-photon light induction in vivo. They can produce targeted, sparse and strong labeling of individual neurons by modifying multiple loci within mouse and zebrafish genomes. In combination with other genetic strategies, they allow intersectional targeting of different neuronal classes. In the mouse cortex they enable sparse labeling and whole-brain morphological reconstructions of individual neurons. Furthermore, these enzymes allow single-cell two-photon targeted genetic modifications and can be used in combination with functional optical indicators with minimal interference. In summary, RecVs enable spatiotemporally-precise optogenomic modifications that can facilitate detailed single-cell analysis of neural circuits by linking genetic identity, morphology, connectivity and function.
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8
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Abstract
Cre-mediated recombination has become a powerful tool to confine gene deletions (conditional knockouts) or overexpression of genes (conditional knockin/overexpression). By spatiotemporal restriction of genetic manipulations, major problems of classical knockouts such as embryonic lethality or pleiotropy can be circumvented. Furthermore, Cre-mediated recombination has broad applications in the analysis of the cellular behavior of subpopulations and cell types as well as for genetic fate mapping. This chapter gives an overview about applications for the Cre/LoxP system and their execution.
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Affiliation(s)
- Claudius F Kratochwil
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Filippo M Rijli
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
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9
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Affiliation(s)
- Ede A Rancz
- Cortical Circuits Laboratory, Francis Crick Institute, London, UK
| | - Andreas T Schaefer
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, UK, and the Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
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10
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Reichert H. How the humble insect brain became a powerful experimental model system. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:879-889. [PMID: 28831545 DOI: 10.1007/s00359-017-1206-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/10/2017] [Accepted: 08/10/2017] [Indexed: 10/19/2022]
Abstract
In the 21st century, neurobiological studies focused on the insect brain are revealing unprecedented insight into the molecular, cellular, developmental, and circuit aspects of brain organization and function, notably in the genetic model system of Drosophila melanogaster. Underlying this accelerating progress in understanding the insect brain is a century-long history of ground breaking experimental investigation, methodological advance, and conceptual insight catalyzed by the integration of two emerging research fields, neuroscience and genetics. This review traces some of the key early steps in this remarkable historical scientific adventure of exploring the brain of "these apparently humble representatives of life".
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11
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Abstract
TDP-43 is a key disease protein for amyotrophic lateral sclerosis but how it drives motor neuron degeneration remains unresolved. A new study has modeled TDP-43 age-dependent axonal death in the Drosophila leg and used a powerful forward genetic screen to identify three novel suppressor genes.
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Affiliation(s)
- Matthew D Figley
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Neuroscience Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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12
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Weissman TA, Pan YA. Brainbow: new resources and emerging biological applications for multicolor genetic labeling and analysis. Genetics 2015; 199:293-306. [PMID: 25657347 PMCID: PMC4317644 DOI: 10.1534/genetics.114.172510] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 12/17/2014] [Indexed: 12/21/2022] Open
Abstract
Brainbow is a genetic cell-labeling technique where hundreds of different hues can be generated by stochastic and combinatorial expression of a few spectrally distinct fluorescent proteins. Unique color profiles can be used as cellular identification tags for multiple applications such as tracing axons through the nervous system, following individual cells during development, or analyzing cell lineage. In recent years, Brainbow and other combinatorial expression strategies have expanded from the mouse nervous system to other model organisms and a wide variety of tissues. Particularly exciting is the application of Brainbow in lineage tracing, where this technique has been instrumental in parsing out complex cellular relationships during organogenesis. Here we review recent findings, new technical improvements, and exciting potential genetic and genomic applications for harnessing this colorful technique in anatomical, developmental, and genetic studies.
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Affiliation(s)
- Tamily A Weissman
- Department of Biology, Lewis and Clark College, Portland, Oregon 97219
| | - Y Albert Pan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912 Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912 James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30912
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13
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Ajjuri RR, Hall M, Reiter LT, O’Donnell JM. Drosophila. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00005-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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14
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Wang L, Zeng X, Ryoo HD, Jasper H. Integration of UPRER and oxidative stress signaling in the control of intestinal stem cell proliferation. PLoS Genet 2014; 10:e1004568. [PMID: 25166757 PMCID: PMC4148219 DOI: 10.1371/journal.pgen.1004568] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 07/01/2014] [Indexed: 11/18/2022] Open
Abstract
The Unfolded Protein Response of the endoplasmic reticulum (UPRER) controls proteostasis by adjusting the protein folding capacity of the ER to environmental and cell-intrinsic conditions. In metazoans, loss of proteostasis results in degenerative and proliferative diseases and cancers. The cellular and molecular mechanisms causing these phenotypes remain poorly understood. Here we show that the UPRER is a critical regulator of intestinal stem cell (ISC) quiescence in Drosophilamelanogaster. We find that ISCs require activation of the UPRER for regenerative responses, but that a tissue-wide increase in ER stress triggers ISC hyperproliferation and epithelial dysplasia in aging animals. These effects are mediated by ISC-specific redox signaling through Jun-N-terminal Kinase (JNK) and the transcription factor CncC. Our results identify a signaling network of proteostatic and oxidative stress responses that regulates ISC function and regenerative homeostasis in the intestinal epithelium. Loss of proper protein homeostasis (proteostasis) as well as increased production of reactive oxygen species (ROS) is a hallmark of aging. In complex metazoans, these processes can result in proliferative diseases and cancers. The protein folding capacity of the endoplasmic reticulum (ER) is monitored and maintained by the unfolded protein response of the ER (UPRER). In this study, we identify a coordinated role of UPRER and oxidative stress signaling in regulating the proliferation of intestinal stem cells (ISCs). We find that the ER-stress responsive transcription factor Xbp1 and the ER-associated degradation pathway component Hrd1 are sufficient and required cell autonomously in ISCs to limit their proliferative activity. This function is dependent on the activities of the stress sensor JNK and the redox-responsive transcription factor CncC, which we have previously identified as regulators of ISC proliferation. We further show here that promoting ER homeostasis in aging ISCs is sufficient to limit age-associated epithelial dysplasia. Our results establish the integration of UPRER and oxidative stress signaling as a central mechanism promoting regenerative homeostasis in the intestinal epithelium.
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Affiliation(s)
- Lifen Wang
- Buck Institute for Research on Aging, Novato, California, United States of America
| | - Xiankun Zeng
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, United States of America
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Heinrich Jasper
- Buck Institute for Research on Aging, Novato, California, United States of America
- * E-mail:
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15
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Hadas Y, Etlin A, Falk H, Avraham O, Kobiler O, Panet A, Lev-Tov A, Klar A. A 'tool box' for deciphering neuronal circuits in the developing chick spinal cord. Nucleic Acids Res 2014; 42:e148. [PMID: 25147209 PMCID: PMC4231727 DOI: 10.1093/nar/gku750] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The genetic dissection of spinal circuits is an essential new means for understanding the neural basis of mammalian behavior. Molecular targeting of specific neuronal populations, a key instrument in the genetic dissection of neuronal circuits in the mouse model, is a complex and time-demanding process. Here we present a circuit-deciphering 'tool box' for fast, reliable and cheap genetic targeting of neuronal circuits in the developing spinal cord of the chick. We demonstrate targeting of motoneurons and spinal interneurons, mapping of axonal trajectories and synaptic targeting in both single and populations of spinal interneurons, and viral vector-mediated labeling of pre-motoneurons. We also demonstrate fluorescent imaging of the activity pattern of defined spinal neurons during rhythmic motor behavior, and assess the role of channel rhodopsin-targeted population of interneurons in rhythmic behavior using specific photoactivation.
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Affiliation(s)
- Yoav Hadas
- Department of Medical Neurobiology, IMRIC, Hebrew University Medical School, Jerusalem, Israel
| | - Alex Etlin
- Department of Medical Neurobiology, IMRIC, Hebrew University Medical School, Jerusalem, Israel
| | - Haya Falk
- Department of Medical Neurobiology, IMRIC, Hebrew University Medical School, Jerusalem, Israel
| | - Oshri Avraham
- Department of Medical Neurobiology, IMRIC, Hebrew University Medical School, Jerusalem, Israel
| | - Oren Kobiler
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel
| | - Amos Panet
- Department of Biochemistry, IMRIC, Hebrew University Medical School, Jerusalem, Israel
| | - Aharon Lev-Tov
- Department of Medical Neurobiology, IMRIC, Hebrew University Medical School, Jerusalem, Israel
| | - Avihu Klar
- Department of Medical Neurobiology, IMRIC, Hebrew University Medical School, Jerusalem, Israel
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16
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Postiglione MP, Hippenmeyer S. Monitoring neurogenesis in the cerebral cortex: an update. FUTURE NEUROLOGY 2014. [DOI: 10.2217/fnl.14.18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ABSTRACT: The cerebral cortex, the seat of our cognitive abilities, is composed of an intricate network of billions of excitatory projection and inhibitory interneurons. Postmitotic cortical neurons are generated by a diverse set of neural stem cell progenitors within dedicated zones and defined periods of neurogenesis during embryonic development. Disruptions in neurogenesis can lead to alterations in the neuronal cytoarchitecture, which is thought to represent a major underlying cause for several neurological disorders, including microcephaly, autism and epilepsy. Although a number of signaling pathways regulating neurogenesis have been described, the precise cellular and molecular mechanisms regulating the functional neural stem cell properties in cortical neurogenesis remain unclear. Here, we discuss the most up-to-date strategies to monitor the fundamental mechanistic parameters of neuronal progenitor proliferation, and recent advances deciphering the logic and dynamics of neurogenesis.
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Affiliation(s)
- Maria Pia Postiglione
- IST Austria (Institute of Science & Technology Austria), Am Campus 1, A-3400 Klosterneuburg, Austria
| | - Simon Hippenmeyer
- IST Austria (Institute of Science & Technology Austria), Am Campus 1, A-3400 Klosterneuburg, Austria
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17
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Kratochwil CF, Rijli FM. The Cre/Lox system to assess the development of the mouse brain. Methods Mol Biol 2014; 1082:295-313. [PMID: 24048942 DOI: 10.1007/978-1-62703-655-9_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Cre-mediated recombination has become a powerful tool to confine gene deletions (conditional knockouts) or overexpression of genes (conditional knockin/overexpression). By spatiotemporal restriction of genetic manipulations, major problems of classical knockouts such as embryonic lethality can be circumvented. Furthermore Cre-mediated recombination has broad applicability in the analysis of the cellular behavior of subpopulations and cell types as well as for genetic fate mapping. This chapter will give an overview about applications for the Cre/LoxP system and their execution.
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18
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Jara JH, Genç B, Klessner JL, Ozdinler PH. Retrograde labeling, transduction, and genetic targeting allow cellular analysis of corticospinal motor neurons: implications in health and disease. Front Neuroanat 2014; 8:16. [PMID: 24723858 PMCID: PMC3972458 DOI: 10.3389/fnana.2014.00016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 03/10/2014] [Indexed: 12/11/2022] Open
Abstract
Corticospinal motor neurons (CSMN) have a unique ability to receive, integrate, translate, and transmit the cerebral cortex's input toward spinal cord targets and therefore act as a “spokesperson” for the initiation and modulation of voluntary movements that require cortical input. CSMN degeneration has an immense impact on motor neuron circuitry and is one of the underlying causes of numerous neurodegenerative diseases, such as primary lateral sclerosis (PLS), hereditary spastic paraplegia (HSP), and amyotrophic lateral sclerosis (ALS). In addition, CSMN death results in long-term paralysis in spinal cord injury patients. Detailed cellular analyses are crucial to gain a better understanding of the pathologies underlying CSMN degeneration. However, visualizing and identifying these vulnerable neuron populations in the complex and heterogeneous environment of the cerebral cortex have proved challenging. Here, we will review recent developments and current applications of novel strategies that reveal the cellular and molecular basis of CSMN health and vulnerability. Such studies hold promise for building long-term effective treatment solutions in the near future.
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Affiliation(s)
- Javier H Jara
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Barış Genç
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Jodi L Klessner
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - P Hande Ozdinler
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA ; Robert H. Lurie Cancer Center, Feinberg School of Medicine, Northwestern University Chicago, IL, USA ; Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University Chicago IL, USA
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19
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Abstract
Fate maps, by defining the relationship between embryonic tissue organization and postnatal tissue structure, are one of the most important tools on hand to developmental biologists. In the past, generating such maps in mice was hindered by their in utero development limiting the physical access required for traditional methods involving tracer injection or cell transplantation. No longer is physical access a requirement. Innovations over the past decade have led to genetic techniques that offer means to "deliver" cell lineage tracers noninvasively. Such "genetic fate mapping" approaches employ transgenic strategies to express genetically encoded site-specific recombinases in a cell type-specific manner to switch on expression of a cell-heritable reporter transgene as lineage tracer. The behaviors and fate of marked cells and their progeny can then be explored and their contributions to different tissues examined. Here, we review the basic concepts of genetic fate mapping and consider the strengths and limitations for their application. We also explore two refinements of this approach that lend improved spatial and temporal resolution: (1) Intersectional and subtractive genetic fate mapping and (2) Genetic inducible fate mapping.
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Affiliation(s)
- Patricia Jensen
- Laboratory of Neurobiology, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, NC, USA
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20
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Kirchmaier S, Höckendorf B, Möller EK, Bornhorst D, Spitz F, Wittbrodt J. Efficient site-specific transgenesis and enhancer activity tests in medaka using PhiC31 integrase. Development 2013; 140:4287-95. [PMID: 24048591 PMCID: PMC3809364 DOI: 10.1242/dev.096081] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Established transgenesis methods for fish model systems allow efficient genomic integration of transgenes. However, thus far a way of controlling copy number and integration sites has not been available, leading to variable transgene expression caused by position effects. The integration of transgenes at predefined genomic positions enables the direct comparison of different transgenes, thereby improving time and cost efficiency. Here, we report an efficient PhiC31-based site-specific transgenesis system for medaka. This system includes features that allow the pre-selection of successfully targeted integrations early on in the injected generation. Pre-selected embryos transmit the correctly integrated transgene through the germline with high efficiency. The landing site design enables a variety of applications, such as reporter and enhancer switch, in addition to the integration of any insert. Importantly, this allows assaying of enhancer activity in a site-specific manner without requiring germline transmission, thus speeding up large-scale analyses of regulatory elements.
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Affiliation(s)
- Stephan Kirchmaier
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
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21
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Hippenmeyer S. Dissection of gene function at clonal level using mosaic analysis with double markers. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s11515-013-1279-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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22
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Ninkovic J, Götz M. Fate specification in the adult brain - lessons for eliciting neurogenesis from glial cells. Bioessays 2013; 35:242-52. [DOI: 10.1002/bies.201200108] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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23
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Urbanska M, Gozdz A, Swiech LJ, Jaworski J. Mammalian target of rapamycin complex 1 (mTORC1) and 2 (mTORC2) control the dendritic arbor morphology of hippocampal neurons. J Biol Chem 2012; 287:30240-56. [PMID: 22810227 DOI: 10.1074/jbc.m112.374405] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dendrites are the main site of information input into neurons. Their development is a multistep process controlled by mammalian target of rapamycin (mTOR) among other proteins. mTOR is a serine/threonine protein kinase that forms two functionally distinct complexes in mammalian cells: mTORC1 and mTORC2. However, the one that contributes to mammalian neuron development remains unknown. This work used short hairpin RNA against Raptor and Rictor, unique components of mTORC1 and mTORC2, respectively, to dissect mTORC involvement in this process. We provide evidence that both mTOR complexes are crucial for the proper dendritic arbor morphology of hippocampal neurons. These two complexes are required for dendritic development both under basal conditions and upon the induction of mTOR-dependent dendritic growth. We also identified Akt as a downstream effector of mTORC2 needed for proper dendritic arbor morphology, the action of which required mTORC1 and p70S6K1.
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Affiliation(s)
- Malgorzata Urbanska
- International Institute of Molecular and Cell Biology, 02-109, Warsaw, Poland
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24
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Emoto K. Signaling mechanisms that coordinate the development and maintenance of dendritic fields. Curr Opin Neurobiol 2012; 22:805-11. [PMID: 22575709 DOI: 10.1016/j.conb.2012.04.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 04/09/2012] [Indexed: 10/28/2022]
Abstract
The establishment of a dendritic tree is a highly dynamic process characterized by extension and retraction of branches, followed by stabilization of existing dendrites and synaptic connections. To properly cover the receptive fields, all of these processes are tightly coordinated at all time points. Recent in vivo studies suggest that several signaling pathways, including Hippo pathway and epigenetic mechanisms, play important roles in maintenance of matured dendrites. This review focuses on the current molecular understanding of how established dendritic fields in functional neuronal circuits are maintained in the brain. The relevance of this knowledge to the pathological mechanisms underlying some neurodegenerative disorders is also discussed.
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Affiliation(s)
- Kazuo Emoto
- Department of Cell Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan.
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25
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Tasic B, Miyamichi K, Hippenmeyer S, Dani VS, Zeng H, Joo W, Zong H, Chen-Tsai Y, Luo L. Extensions of MADM (mosaic analysis with double markers) in mice. PLoS One 2012; 7:e33332. [PMID: 22479386 PMCID: PMC3314016 DOI: 10.1371/journal.pone.0033332] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 02/07/2012] [Indexed: 01/10/2023] Open
Abstract
Mosaic Analysis with Double Markers (MADM) is a method for generating genetically mosaic mice, in which sibling mutant and wild-type cells are labeled with different fluorescent markers. It is a powerful tool that enables analysis of gene function at the single cell level in vivo. It requires transgenic cassettes to be located between the centromere and the mutation in the gene of interest on the same chromosome. Here we compare procedures for introduction of MADM cassettes into new loci in the mouse genome, and describe new approaches for expanding the utility of MADM. We show that: 1) Targeted homologous recombination outperforms random transgenesis in generation of reliably expressed MADM cassettes, 2) MADM cassettes in new genomic loci need to be validated for biallelic and ubiquitous expression, 3) Recombination between MADM cassettes on different chromosomes can be used to study reciprocal chromosomal deletions/duplications, and 4) MADM can be modified to permit transgene expression by combining it with a binary expression system. The advances described in this study expand current, and enable new and more versatile applications of MADM.
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Affiliation(s)
- Bosiljka Tasic
- Department of Biology, Howard Hughes Medical Insitute, Stanford University, California, United States of America.
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26
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Optical highlighter molecules in neurobiology. Curr Opin Neurobiol 2011; 22:111-20. [PMID: 22129781 DOI: 10.1016/j.conb.2011.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 11/05/2011] [Accepted: 11/07/2011] [Indexed: 12/18/2022]
Abstract
The development of advanced optical methods has played a key role in propelling progress in neurobiology. Genetically-encoded fluorescent molecules found in nature have enabled labeling of individual neurons to study their physiology and anatomy. Here we discuss the recent use of both native and synthetic optical highlighter proteins to address key problems in neurobiology, including questions relevant to synaptic function, neuroanatomy, and the organization of neural circuits.
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27
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Abstract
Plastic changes at the presynaptic sites of the mushroom body (MB) principal neurons called Kenyon cells (KCs) are considered to represent a neuronal substrate underlying olfactory learning and memory. It is generally believed that presynaptic and postsynaptic sites of KCs are spatially segregated. In the MB calyx, KCs receive olfactory input from projection neurons (PNs) on their dendrites. Their presynaptic sites, however, are thought to be restricted to the axonal projections within the MB lobes. Here, we show that KCs also form presynapses along their calycal dendrites, by using novel transgenic tools for visualizing presynaptic active zones and postsynaptic densities. At these presynapses, vesicle release following stimulation could be observed. They reside at a distance from the PN input into the KC dendrites, suggesting that regions of presynaptic and postsynaptic differentiation are segregated along individual KC dendrites. KC presynapses are present in γ-type KCs that support short- and long-term memory in adult flies and larvae. They can also be observed in α/β-type KCs, which are involved in memory retrieval, but not in α'/β'-type KCs, which are implicated in memory acquisition and consolidation. We hypothesize that, as in mammals, recurrent activity loops might operate for memory retrieval in the fly olfactory system. The newly identified KC-derived presynapses in the calyx are, inter alia, candidate sites for the formation of memory traces during olfactory learning.
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28
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Abstract
Genetically engineered mouse models have significantly contributed to our understanding of cancer biology. They have proven to be useful in validating gene functions, identifying novel cancer genes and tumor biomarkers, gaining insight into the molecular and cellular mechanisms underlying tumor initiation and multistage processes of tumorigenesis, and providing better clinical models in which to test novel therapeutic strategies. However, mice still have significant limitations in modeling human cancer, including species-specific differences and inaccurate recapitulation of de novo human tumor development. Future challenges in mouse modeling include the generation of clinically relevant mouse models that recapitulate the molecular, cellular, and genomic events of human cancers and clinical response as well as the development of technologies that allow for efficient in vivo imaging and high-throughput screening in mice.
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Affiliation(s)
- Dong-Joo Cheon
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA
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29
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30
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Dong J, Tong T, Reynado AM, Rosen JM, Huang S, Li Y. Genetic manipulation of individual somatic mammary cells in vivo reveals a master role of STAT5a in inducing alveolar fate commitment and lactogenesis even in the absence of ovarian hormones. Dev Biol 2010; 346:196-203. [PMID: 20691178 DOI: 10.1016/j.ydbio.2010.07.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 06/23/2010] [Accepted: 07/16/2010] [Indexed: 01/14/2023]
Abstract
Assessing the molecular control of development and cell fate in individual cells in the intact mammary epithelium has not been possible to date. By exploiting an intraductal retrovirus (RCAS)-mediated gene delivery method to introduce a marker gene, we found that ductal epithelial cells are turned over with a half time of approximately 1month in adult virgin mice. However, following RCAS-mediated introduction of a constitutively activated STAT5a (caSTAT5a), caSTAT5a-activated ductal epithelial cells expand and replace other cells in the epithelium, eventually forming a mammary gland resembling that in a late pregnant mouse, suggesting that STAT5a activation alone is sufficient to mediate pregnancy-induced mammary cell expansion, alveolar cell fate commitment, and lactogenesis. Furthermore, such caSTAT5a-induced alveolar differentiation does not require ovarian functions, although caSTAT5a-induced cell proliferation is partly reduced in ovariectomized mice. In conclusion, in this first report of studying the developmental role of a gene in a few cells in a normally developed virgin mammary ductal tree, STAT5a activation causes alveolar fate commitment and lactogenesis, and with the help of ovarian hormones, drives alveolar expansion.
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Affiliation(s)
- Jie Dong
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030, USA
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31
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Potter CJ, Tasic B, Russler EV, Liang L, Luo L. The Q system: a repressible binary system for transgene expression, lineage tracing, and mosaic analysis. Cell 2010; 141:536-48. [PMID: 20434990 DOI: 10.1016/j.cell.2010.02.025] [Citation(s) in RCA: 402] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 01/07/2010] [Accepted: 02/16/2010] [Indexed: 02/05/2023]
Abstract
We describe a new repressible binary expression system based on the regulatory genes from the Neurospora qa gene cluster. This "Q system" offers attractive features for transgene expression in Drosophila and mammalian cells: low basal expression in the absence of the transcriptional activator QF, high QF-induced expression, and QF repression by its repressor QS. Additionally, feeding flies quinic acid can relieve QS repression. The Q system offers many applications, including (1) intersectional "logic gates" with the GAL4 system for manipulating transgene expression patterns, (2) GAL4-independent MARCM analysis, and (3) coupled MARCM analysis to independently visualize and genetically manipulate siblings from any cell division. We demonstrate the utility of the Q system in determining cell division patterns of a neuronal lineage and gene function in cell growth and proliferation, and in dissecting neurons responsible for olfactory attraction. The Q system can be expanded to other uses in Drosophila and to any organism conducive to transgenesis.
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32
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Woodruff A, Xu Q, Anderson SA, Yuste R. Depolarizing effect of neocortical chandelier neurons. Front Neural Circuits 2009; 3:15. [PMID: 19876404 PMCID: PMC2769545 DOI: 10.3389/neuro.04.015.2009] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 09/30/2009] [Indexed: 11/13/2022] Open
Abstract
Chandelier (or axo-axonic) cells are one of the most distinctive types of GABAergic interneurons in the cortex. Although they have traditionally been considered inhibitory neurons, data from rat and human neocortical preparations suggest that chandelier cells have a depolarizing effect on pyramidal neurons at resting membrane potential, and could even activate synaptic chains of neurons. At the same time, recent results from rat hippocampal chandeliers indicate a predominantly inhibitory effect on their postsynaptic targets. To better understand the function of chandelier neurons, we generated Nkx2.1Cre MADM mice, a strain of genetically engineered animals that, by expressing GFP in a subset of neocortical interneurons, enable the identification and targeting of chandelier cells in living brain slices. Using these mice, we characterized the basic electrophysiological properties of a homogeneous population of chandelier neurons from upper layers of somatosensory cortical slices. These chandelier cells have characteristic axon cartridges and stereotypical electrophysiological features, distinguishable from basket cells. To investigate the effect of chandelier cells on target neurons, we performed paired recordings from chandeliers and postsynaptic pyramidal cells. In both perforated patch and cell-attached configurations, chandelier PSPs have in every case a reversal potential that is depolarized from rest. Our results support the idea that chandelier cells depolarize pyramidal neurons and could potentially have an excitatory effect on the network at rest.
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Affiliation(s)
- Alan Woodruff
- Howard Hughes Medical Institute, Department Biological Sciences, Columbia University New York, NY, USA
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33
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Wang SZ, Liu BH, Tao HW, Xia K, Zhang LI. A genetic strategy for stochastic gene activation with regulated sparseness (STARS). PLoS One 2009; 4:e4200. [PMID: 19145242 PMCID: PMC2615212 DOI: 10.1371/journal.pone.0004200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2008] [Accepted: 12/08/2008] [Indexed: 01/01/2023] Open
Abstract
It remains a challenge to establish a straightforward genetic approach for controlling the probability of gene activation or knockout at a desired level. Here, we developed a method termed STARS: stochastic gene activation with genetically regulated sparseness. The stochastic expression was achieved by two cross-linked, mutually-exclusive Cre-mediated recombinations. The stochastic level was further controlled by regulating Cre/lox reaction kinetics through varying the intrachromosomal distance between the lox sites mediating one of the recombinations. In mammalian cell lines stably transfected with a single copy of different STARS transgenes, the activation/knockout of reporter genes was specifically controlled to occur in from 5% to 50% of the cell population. STARS can potentially provide a convenient way for genetic labeling as well as gene expression/knockout in a population of cells with a desired sparseness level.
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Affiliation(s)
- Sheng-zhi Wang
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Bao-hua Liu
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Huizhong W. Tao
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Kun Xia
- The State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, People's Republic of China
| | - Li I. Zhang
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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34
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Breunig JJ, Arellano JI, Macklis JD, Rakic P. Everything that glitters isn't gold: a critical review of postnatal neural precursor analyses. Cell Stem Cell 2008; 1:612-27. [PMID: 18371403 DOI: 10.1016/j.stem.2007.11.008] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Adult neurogenesis research has made enormous strides in the last decade but has been complicated by several failures to replicate promising findings. Prevalent use of highly sensitive methods with inherent sources of error has led to extraordinary conclusions without adequate crossvalidation. Perhaps the biggest culprit is the reliance on molecules involved in DNA synthesis and genetic markers to indicate neuronal neogenesis. In this Protocol Review, we present an overview of common methodological issues in the field and suggest alternative approaches, including viral vectors, siRNA, and inducible transgenic/knockout mice. A multipronged approach will enhance the overall rigor of research on stem cell biology and related fields by allowing increased replication of findings between groups and across systems.
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Affiliation(s)
- Joshua J Breunig
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, USA
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35
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Circuit reconstruction tools today. Curr Opin Neurobiol 2007; 17:601-8. [PMID: 18082394 DOI: 10.1016/j.conb.2007.11.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 10/17/2007] [Accepted: 11/03/2007] [Indexed: 11/22/2022]
Abstract
To understand how a brain processes information, we must understand the structure of its neural circuits-especially circuit interconnection topologies and the cell and synapse molecular architectures that determine circuit-signaling dynamics. Our information on these key aspects of neural circuit structure has remained incomplete and fragmentary, however, because of limitations of the best available imaging methods. Now, new transgenic tool mice and new image acquisition tools appear poised to permit very significant advances in our abilities to reconstruct circuit connection topologies and molecular architectures.
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36
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Luan H, White BH. Combinatorial methods for refined neuronal gene targeting. Curr Opin Neurobiol 2007; 17:572-80. [DOI: 10.1016/j.conb.2007.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 10/01/2007] [Accepted: 10/04/2007] [Indexed: 01/13/2023]
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