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Kato A. Development of conjugation-mediated versatile site-specific single-copy luciferase fusion system. J GEN APPL MICROBIOL 2024; 69:318-326. [PMID: 37940551 DOI: 10.2323/jgam.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
There are a number of reporter systems that are useful for gene expression analysis in bacteria. However, at least in Salmonella, a versatile and simple luciferase reporter system that can be integrated precisely behind a promoter or gene of interest on a chromosome is not currently available. The luciferase operon luxCDABE from Photorhabdus luminescens has several advantages, including brightness, wide linear range, absence in most bacteria, stability at high temperature, and no substrate addition required for the assay. Here, a conjugation-mediated site-specific single-copy luciferase fusion system is developed. A reporter plasmid containing the conditional replication origin R6Kgγ, FRT-luxCDABE, and KmR marker was designed to be incorporated into the FRT site behind the promoter or gene of interest on the chromosome in cells expressing FLP. However, when this reporter plasmid was electroporated directly into such a S. enterica strain, no colonies appeared, likely due to the low transformation efficiency of this relatively large plasmid DNA. Meanwhile, the same reporter plasmid was successfully introduced and launched as an insert of an FRT-containing conjugative transfer plasmid from a mating E. coli strain to the same recipient S. enterica strain, as well as Citrobacter koseri. RcsB-dependent inducible luminescence from the constructed wzc-luxCDABE strains was confirmed. This system is feasible for detecting very low levels of transcription, even in Gram-negative bacterial species that are relatively difficult to genetically manipulate.
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Affiliation(s)
- Akinori Kato
- Department of Advanced Bioscience, Graduate School of Agriculture, Kindai University
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2
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Zhao C, Ries C, Du Y, Zhang J, Sakimura K, Itoi K, Deussing JM. Differential CRH expression level determines efficiency of Cre- and Flp-dependent recombination. Front Neurosci 2023; 17:1163462. [PMID: 37599997 PMCID: PMC10434532 DOI: 10.3389/fnins.2023.1163462] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/21/2023] [Indexed: 08/22/2023] Open
Abstract
Corticotropin-releasing hormone expressing (CRH+) neurons are distributed throughout the brain and play a crucial role in shaping the stress responses. Mouse models expressing site-specific recombinases (SSRs) or reporter genes are important tools providing genetic access to defined cell types and have been widely used to address CRH+ neurons and connected brain circuits. Here, we investigated a recently generated CRH-FlpO driver line expanding the CRH system-related tool box. We directly compared it to a previously established and widely used CRH-Cre line with respect to the FlpO expression pattern and recombination efficiency. In the brain, FlpO mRNA distribution fully recapitulates the expression pattern of endogenous Crh. Combining both Crh locus driven SSRs driver lines with appropriate reporters revealed an overall coherence of respective spatial patterns of reporter gene activation validating CRH-FlpO mice as a valuable tool complementing existing CRH-Cre and reporter lines. However, a substantially lower number of reporter-expressing neurons was discerned in CRH-FlpO mice. Using an additional CRH reporter mouse line (CRH-Venus) and a mouse line allowing for conversion of Cre into FlpO activity (CAG-LSL-FlpO) in combination with intersectional and subtractive mouse genetic approaches, we were able to demonstrate that the reduced number of tdTomato reporter expressing CRH+ neurons can be ascribed to the lower recombination efficiency of FlpO compared to Cre recombinase. This discrepancy particularly manifests under conditions of low CRH expression and can be overcome by utilizing homozygous CRH-FlpO mice. These findings have direct experimental implications which have to be carefully considered when targeting CRH+ neurons using CRH-FlpO mice. However, the lower FlpO-dependent recombination efficiency also entails advantages as it provides a broader dynamic range of expression allowing for the visualization of cells showing stress-induced CRH expression which is not detectable in highly sensitive CRH-Cre mice as Cre-mediated recombination has largely been completed in all cells generally possessing the capacity to express CRH. These findings underscore the importance of a comprehensive evaluation of novel SSR driver lines prior to their application.
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Affiliation(s)
- Chen Zhao
- Molecular Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Clemens Ries
- Molecular Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Ying Du
- Molecular Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Jingwei Zhang
- Molecular Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Keiichi Itoi
- Super-Network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Jan M. Deussing
- Molecular Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
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Lusk SJ, McKinney A, Hunt PJ, Fahey PG, Patel J, Chang A, Sun JJ, Martinez VK, Zhu PJ, Egbert JR, Allen G, Jiang X, Arenkiel BR, Tolias AS, Costa-Mattioli M, Ray RS. A CRISPR toolbox for generating intersectional genetic mouse models for functional, molecular, and anatomical circuit mapping. BMC Biol 2022; 20:28. [PMID: 35086530 PMCID: PMC8796356 DOI: 10.1186/s12915-022-01227-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 01/06/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The functional understanding of genetic interaction networks and cellular mechanisms governing health and disease requires the dissection, and multifaceted study, of discrete cell subtypes in developing and adult animal models. Recombinase-driven expression of transgenic effector alleles represents a significant and powerful approach to delineate cell populations for functional, molecular, and anatomical studies. In addition to single recombinase systems, the expression of two recombinases in distinct, but partially overlapping, populations allows for more defined target expression. Although the application of this method is becoming increasingly popular, its experimental implementation has been broadly restricted to manipulations of a limited set of common alleles that are often commercially produced at great expense, with costs and technical challenges associated with production of intersectional mouse lines hindering customized approaches to many researchers. Here, we present a simplified CRISPR toolkit for rapid, inexpensive, and facile intersectional allele production. RESULTS Briefly, we produced 7 intersectional mouse lines using a dual recombinase system, one mouse line with a single recombinase system, and three embryonic stem (ES) cell lines that are designed to study the way functional, molecular, and anatomical features relate to each other in building circuits that underlie physiology and behavior. As a proof-of-principle, we applied three of these lines to different neuronal populations for anatomical mapping and functional in vivo investigation of respiratory control. We also generated a mouse line with a single recombinase-responsive allele that controls the expression of the calcium sensor Twitch-2B. This mouse line was applied globally to study the effects of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on calcium release in the ovarian follicle. CONCLUSIONS The lines presented here are representative examples of outcomes possible with the successful application of our genetic toolkit for the facile development of diverse, modifiable animal models. This toolkit will allow labs to create single or dual recombinase effector lines easily for any cell population or subpopulation of interest when paired with the appropriate Cre and FLP recombinase mouse lines or viral vectors. We have made our tools and derivative intersectional mouse and ES cell lines openly available for non-commercial use through publicly curated repositories for plasmid DNA, ES cells, and transgenic mouse lines.
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Affiliation(s)
- Savannah J Lusk
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Andrew McKinney
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Patrick J Hunt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Paul G Fahey
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Jay Patel
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Andersen Chang
- Department of Statistics, Rice University, Houston, TX, USA
| | - Jenny J Sun
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Vena K Martinez
- Department of Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Ping Jun Zhu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Jeremy R Egbert
- Department of Cell Biology, University of Connecticut, Farmington, CT, USA
| | - Genevera Allen
- Department of Statistics, Computer Science, and Electrical and Computer Engineering, Rice University, Houston, TX, USA
- Neurological Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Xiaolong Jiang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- McNair Medical Institute, Houston, TX, USA
| | - Andreas S Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | | | - Russell S Ray
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
- McNair Medical Institute, Houston, TX, USA.
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Ubina T, Vahedi-Hunter T, Agnew-Svoboda W, Wong W, Gupta A, Santhakumar V, Riccomagno MM. ExBoX - a simple Boolean exclusion strategy to drive expression in neurons. J Cell Sci 2021; 134:272538. [PMID: 34515305 PMCID: PMC8572001 DOI: 10.1242/jcs.257212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 09/03/2021] [Indexed: 11/20/2022] Open
Abstract
The advent of modern single-cell biology has revealed the striking molecular diversity of cell populations once thought to be more homogeneous. This newly appreciated complexity has made intersectional genetic approaches essential to understanding and probing cellular heterogeneity at the functional level. Here, we build on previous knowledge to develop a simple adeno-associated virus (AAV)-based approach to define specific subpopulations of cells by Boolean exclusion logic (AND NOT). This expression by Boolean exclusion (ExBoX) system encodes for a gene of interest that is turned on by a particular recombinase (Cre or FlpO) and turned off by another. ExBoX allows for the specific transcription of a gene of interest in cells expressing only the activating recombinase, but not in cells expressing both. We show the ability of the ExBoX system to tightly regulate expression of fluorescent reporters in vitro and in vivo, and further demonstrate the adaptability of the system by achieving expression of a variety of virally delivered coding sequences in the mouse brain. This simple strategy will expand the molecular toolkit available for cell- and time-specific gene expression in a variety of systems. Summary: The generation of a novel AAV-based intersectional approach to define and target specific subpopulations of cells in time and space via a Expression by Boolean Exclusion (ExBoX) system.
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Affiliation(s)
- Teresa Ubina
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Tyler Vahedi-Hunter
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Will Agnew-Svoboda
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Wenny Wong
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Akshay Gupta
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Vijayalakshmi Santhakumar
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Martin M Riccomagno
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
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Warnock ND, Atcheson E, McCoy C, Whiteside L, Dalzell JJ. Highly divergent neuropeptide - non-coding RNA regulatory networks underpin variant host-finding behaviours in Steinernema species infective juveniles. Int J Parasitol 2021; 51:693-698. [PMID: 33848496 DOI: 10.1016/j.ijpara.2021.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 10/21/2022]
Abstract
We conducted a transcriptomic and small RNA analysis of infective juveniles (IJs) from three behaviourally distinct Steinernema species. Substantial variation was found in the expression of shared gene orthologues, revealing gene expression signatures that correlate with behavioural states. Ninety-seven percent of predicted microRNAs are novel to each species. Surprisingly, our data provide evidence of a new family of non-coding transcripts that overlap with neuropeptide gene loci, which are predicted to influence microRNA regulation of neuropeptide genes. These data suggest that differences in neuropeptide gene expression, isoform variation, and small RNA interactions could contribute to behavioural differences within the Steinernema genus.
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Affiliation(s)
- Neil D Warnock
- School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Erwan Atcheson
- School of Biological Sciences, Queen's University Belfast, Belfast, UK.
| | - Ciaran McCoy
- School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Louise Whiteside
- School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | - Johnathan J Dalzell
- School of Biological Sciences, Queen's University Belfast, Belfast, UK; Agri-Food and Biosciences Institute (AFBI), Belfast, UK
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Hafner G, Witte M, Guy J, Subhashini N, Fenno LE, Ramakrishnan C, Kim YS, Deisseroth K, Callaway EM, Oberhuber M, Conzelmann KK, Staiger JF. Mapping Brain-Wide Afferent Inputs of Parvalbumin-Expressing GABAergic Neurons in Barrel Cortex Reveals Local and Long-Range Circuit Motifs. Cell Rep 2019; 28:3450-3461.e8. [PMID: 31553913 DOI: 10.1016/j.celrep.2019.08.064] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 07/23/2019] [Accepted: 08/21/2019] [Indexed: 12/22/2022] Open
Abstract
Parvalbumin (PV)-expressing GABAergic neurons are the largest class of inhibitory neocortical cells. We visualize brain-wide, monosynaptic inputs to PV neurons in mouse barrel cortex. We develop intersectional rabies virus tracing to specifically target GABAergic PV cells and exclude a small fraction of excitatory PV cells from our starter population. Local inputs are mainly from layer (L) IV and excitatory cells. A small number of inhibitory inputs originate from LI neurons, which connect to LII/III PV neurons. Long-range inputs originate mainly from other sensory cortices and the thalamus. In visual cortex, most transsynaptically labeled neurons are located in LIV, which contains a molecularly mixed population of projection neurons with putative functional similarity to LIII neurons. This study expands our knowledge of the brain-wide circuits in which PV neurons are embedded and introduces intersectional rabies virus tracing as an applicable tool to dissect the circuitry of more clearly defined cell types.
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7
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Fenno LE, Ramakrishnan C, Kim YS, Evans KE, Lo M, Vesuna S, Inoue M, Cheung KYM, Yuen E, Pichamoorthy N, Hong ASO, Deisseroth K. Comprehensive Dual- and Triple-Feature Intersectional Single-Vector Delivery of Diverse Functional Payloads to Cells of Behaving Mammals. Neuron 2020; 107:836-853.e11. [PMID: 32574559 PMCID: PMC7687746 DOI: 10.1016/j.neuron.2020.06.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/08/2020] [Accepted: 05/29/2020] [Indexed: 01/12/2023]
Abstract
The resolution and dimensionality with which biologists can characterize cell types have expanded dramatically in recent years, and intersectional consideration of such features (e.g., multiple gene expression and anatomical parameters) is increasingly understood to be essential. At the same time, genetically targeted technology for writing in and reading out activity patterns for cells in living organisms has enabled causal investigation in physiology and behavior; however, cell-type-specific delivery of these tools (including microbial opsins for optogenetics and genetically encoded Ca2+ indicators) has thus far fallen short of versatile targeting to cells jointly defined by many individually selected features. Here, we develop a comprehensive intersectional targeting toolbox including 39 novel vectors for joint-feature-targeted delivery of 13 molecular payloads (including opsins, indicators, and fluorophores), systematic approaches for development and optimization of new intersectional tools, hardware for in vivo monitoring of expression dynamics, and the first versatile single-virus tools (Triplesect) that enable targeting of triply defined cell types.
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Affiliation(s)
- Lief E Fenno
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Charu Ramakrishnan
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kathryn E Evans
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Maisie Lo
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Sam Vesuna
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Masatoshi Inoue
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kathy Y M Cheung
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Elle Yuen
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | | | - Alice S O Hong
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Karl Deisseroth
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA; Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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8
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Fischer KB, Collins HK, Callaway EM. Sources of off-target expression from recombinase-dependent AAV vectors and mitigation with cross-over insensitive ATG-out vectors. Proc Natl Acad Sci U S A 2019:201915974. [PMID: 31843925 DOI: 10.1073/pnas.1915974116] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In combination with transgenic mouse lines expressing Cre or Flp recombinases in defined cell types, recombinase-dependent adeno-associated viruses (AAVs) have become the tool of choice for localized cell-type-targeted gene expression. Unfortunately, applications of this technique when expressing highly sensitive transgenes are impeded by off-target, or "leak" expression, from recombinase-dependent AAVs. We investigated this phenomenon and find that leak expression is mediated by both infrequent transcription from the inverted transgene in recombinant-dependent AAV designs and recombination events during bacterial AAV plasmid production. Recombination in bacteria is mediated by homology across the antiparallel recombinase-specific recognition sites present in recombinase-dependent designs. To address both of these issues we designed an AAV vector that uses mutant "cross-over insensitive" recognition sites combined with an "ATG-out" design. We show that these CIAO (cross-over insensitive ATG-out) vectors virtually eliminate leak expression. CIAO vectors provide reliable and targeted transgene expression and are extremely useful for recombinase-dependent expression of highly sensitive transgenes.
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9
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Jensen IS, Yuan J, He J, Lin L, Sander B, Golas MM. The FlpTRAP system for purification of specific, endogenous chromatin regions. Anal Biochem 2019; 587:113418. [PMID: 31520595 DOI: 10.1016/j.ab.2019.113418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/07/2019] [Accepted: 09/08/2019] [Indexed: 10/26/2022]
Abstract
The repressor element 1-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) binds to repressor element 1/neuron-restrictive silencer element (RE1/NRSE) sites in the genome and recruits effector proteins to repress its target genes. Here, we developed the FlpTRAP system to isolate endogenously assembled DNA-protein complexes such as the REST/NRSF complex. In the FlpTRAP system, we take advantage of the step-arrest variant of the Flp recombinase, FlpH305L, which, in the presence of Flp recognition target (FRT) DNA, accumulates as FRT DNA-protein adduct. The FlpTRAP system consists of three elements: (i) FlpH305L-containing cell extracts or isolates, (ii) a cell line engineered to harbor the DNA motif of interest flanked by FRT sites, and (iii) affinity selection steps to isolate the target chromatin. Specifically, 3×FLAG-tagged FlpH305L was expressed in insect cell cultures infected with baculovirus, and cell lysates were prepared. The lysate was used to capture the FRT-SNAP25 RE1/NRSE-FRT chromatin from a human medulloblastoma cell line, and the target RE1/NRSE chromatin was isolated by anti-FLAG immunoaffinity chromatography. Using electrophoretic mobility shift assays (EMSAs) and chromatin immunopurification (ChIP), we show that FlpH305L recognized and bound to the FRT sites. Overall, we suggest the FlpTRAP system as a tool to purify endogenous, specific chromatin loci from eukaryotic cells.
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Affiliation(s)
- Ida S Jensen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Juan Yuan
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Jin He
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Lin Lin
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Bjoern Sander
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark.
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10
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Gershkovich MM, Groß VE, Kaiser A, Prömel S. Pharmacological and functional similarities of the human neuropeptide Y system in C. elegans challenges phylogenetic views on the FLP/NPR system. Cell Commun Signal 2019; 17:123. [PMID: 31533726 DOI: 10.1186/s12964-019-0436-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 09/02/2019] [Indexed: 11/14/2022] Open
Abstract
Background The neuropeptide Y system affects various processes, among others food intake, and is frequently discussed in the context of targeting obesity. Studies in model organisms are indispensable to enable molecular studies in a physiological context. Although the NPY system is evolutionarily conserved in all bilaterians, in the widely used model Caenorhabditis elegans there is controversy on the existence of NPY orthologous molecules. While the FMRFamide-like peptide (FLP)/Neuropeptide receptor-Resemblance (NPR) system in the nematode was initially suggested to be orthologous to the mammalian NPY system, later global phylogenetic studies indicate that FLP/NPR is protostome-specific. Methods We performed a comprehensive pharmacological study of the FLP/NPR system in transfected cells in vitro, and tested for functional substitution in C. elegans knockout strains. Further, we phenotypically compared different flp loss-of-function strains. Differences between groups were compared by ANOVA and post-hoc testing (Dunnett, Bonferroni). Results Our pharmacological analysis of the FLP/NPR system including formerly functionally uncharacterized NPY-like peptides from C. elegans demonstrates that G protein-coupling and ligand requirements for receptor activation are similar to the human NPY system. In vitro and in vivo analyses show cross-reactivity of NPY with the FLP/NPR system manifesting in the ability of the human GPCRs to functionally substitute FLP/NPR signaling in vivo. The high pharmacological/functional similarities enabled us to identify C. elegans FLP-14 as a key molecule in avoidance behavior. Conclusions Our data demonstrate the pharmacological and functional similarities of human NPY and C. elegans NPR systems. This adds a novel perspective to current phylogenetic reconstructions of the neuropeptide Y system. NPY and NPR receptors are pharmacologically so similar that the human receptors can functionally compensate for the C. elegans ones, suggesting orthologous relationships. This is also underlined by the presence of NPY-like peptides and parallels in peptide requirements for receptor activation. Further, the results presented here highlight the potential of this knowledge for physiological as well as molecular studies on neuropeptide GPCRs such as the NPY system in the future.
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11
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Daigle TL, Madisen L, Hage TA, Valley MT, Knoblich U, Larsen RS, Takeno MM, Huang L, Gu H, Larsen R, Mills M, Bosma-Moody A, Siverts LA, Walker M, Graybuck LT, Yao Z, Fong O, Nguyen TN, Garren E, Lenz GH, Chavarha M, Pendergraft J, Harrington J, Hirokawa KE, Harris JA, Nicovich PR, McGraw MJ, Ollerenshaw DR, Smith KA, Baker CA, Ting JT, Sunkin SM, Lecoq J, Lin MZ, Boyden ES, Murphy GJ, da Costa NM, Waters J, Li L, Tasic B, Zeng H. A Suite of Transgenic Driver and Reporter Mouse Lines with Enhanced Brain-Cell-Type Targeting and Functionality. Cell 2019; 174:465-480.e22. [PMID: 30007418 DOI: 10.1016/j.cell.2018.06.035] [Citation(s) in RCA: 414] [Impact Index Per Article: 82.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/12/2018] [Accepted: 06/13/2018] [Indexed: 01/05/2023]
Abstract
Modern genetic approaches are powerful in providing access to diverse cell types in the brain and facilitating the study of their function. Here, we report a large set of driver and reporter transgenic mouse lines, including 23 new driver lines targeting a variety of cortical and subcortical cell populations and 26 new reporter lines expressing an array of molecular tools. In particular, we describe the TIGRE2.0 transgenic platform and introduce Cre-dependent reporter lines that enable optical physiology, optogenetics, and sparse labeling of genetically defined cell populations. TIGRE2.0 reporters broke the barrier in transgene expression level of single-copy targeted-insertion transgenesis in a wide range of neuronal types, along with additional advantage of a simplified breeding strategy compared to our first-generation TIGRE lines. These novel transgenic lines greatly expand the repertoire of high-precision genetic tools available to effectively identify, monitor, and manipulate distinct cell types in the mouse brain.
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Affiliation(s)
- Tanya L Daigle
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Linda Madisen
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Travis A Hage
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - Ulf Knoblich
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Rylan S Larsen
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Marc M Takeno
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Lawrence Huang
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Hong Gu
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Rachael Larsen
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Maya Mills
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | | | - Miranda Walker
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - Zizhen Yao
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Olivia Fong
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - Emma Garren
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Garreck H Lenz
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Mariya Chavarha
- Departments of Neurobiology and Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | | | | | - Julie A Harris
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - Medea J McGraw
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | | | | | | | - Susan M Sunkin
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Jérôme Lecoq
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Michael Z Lin
- Departments of Neurobiology and Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Edward S Boyden
- MIT Media Lab and McGovern Institute, Departments of Biological Engineering and Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Gabe J Murphy
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | | | - Jack Waters
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Lu Li
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Bosiljka Tasic
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA 98109, USA.
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12
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Kakava-Georgiadou N, Zwartkruis MM, Bullich-Vilarrubias C, Luijendijk MCM, Garner KM, van der Plasse G, Adan RAH. An Intersectional Approach to Target Neural Circuits With Cell- and Projection-Type Specificity: Validation in the Mesolimbic Dopamine System. Front Mol Neurosci 2019; 12:49. [PMID: 30873002 PMCID: PMC6403677 DOI: 10.3389/fnmol.2019.00049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/11/2019] [Indexed: 12/12/2022] Open
Abstract
Development of tools to manipulate activity of specific neurons is important for dissecting the function of neural circuits. Viral vectors and conditional transgenic animal lines that target recombinases to specific cells facilitate the successful manipulation and recording of specific subsets of neurons. So far, it has been possible to target neuronal subtypes within a certain brain region based on transcriptional control regions from a gene selectively expressed in those cells or based upon its projections. Nevertheless, there are only a few tools available that combine this and target a neuronal subtype within a projection. We tested a viral vector system, consisting of a canine adenovirus type 2 expressing a Cre-dependent Flp recombinase (CavFlexFlp) and an adeno-associated viral (AAV) vector expressing a Flp-dependent cDNA, which targets neurons in a subtype- and projection-specific manner. As proof of principle we targeted expression of a Designer Receptor Exclusively Activated by Designer Drugs (DREADD) to the dopamine neurons of the mesolimbic projection, which allows the transient activation of neurons by the ligand Clozapine-N-Oxide (CNO). We validated that the system specifically targets dopamine neurons and that chemogenetic activation of these neurons induces an increase in locomotor activity. We thus validated a valuable tool that allows in vivo neuronal activation in a projection- and subtype-specific manner.
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Affiliation(s)
- Nefeli Kakava-Georgiadou
- Division of Neuroscience, Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Maria M Zwartkruis
- Division of Neuroscience, Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands.,Master's Program Neuroscience and Cognition, Utrecht University, Utrecht, Netherlands
| | - Clara Bullich-Vilarrubias
- Division of Neuroscience, Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands.,Master's Program Neuroscience and Cognition, Utrecht University, Utrecht, Netherlands
| | - Mieneke C M Luijendijk
- Division of Neuroscience, Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Keith M Garner
- Division of Neuroscience, Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Geoffrey van der Plasse
- Division of Neuroscience, Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Roger A H Adan
- Division of Neuroscience, Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands.,Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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13
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Jo A, Xu J, Deniz S, Cherian S, DeVries SH, Zhu Y. Intersectional Strategies for Targeting Amacrine and Ganglion Cell Types in the Mouse Retina. Front Neural Circuits 2018; 12:66. [PMID: 30186122 PMCID: PMC6113359 DOI: 10.3389/fncir.2018.00066] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/02/2018] [Indexed: 12/02/2022] Open
Abstract
The mammalian retina harbors over 100 different cell types. To understand how retinal circuits work, it is essential to systematically access each type. A widely used approach for achieving targeted transgene expression exploits promoter-driven Cre lines. However, Cre expression in a given transgenic line in the retina and elsewhere in the brain is rarely confined to a single cell type, contributing ambiguity to the interpretation of results from broadly applied manipulations. To obtain unambiguous information about retinal processing, it is desirable to have strategies for further restricting transgene expression to a few or even to a single cell type. We employed an intersectional strategy based on a Cre/Flp double recombinase system to target amacrine and ganglion cell types in the inner retina. We analyzed expression patterns in seven Flp drivers and then created combinational mouse lines by selective cross breeding with Cre drivers. Breeding with Flp drivers can routinely remove labeling from more than 90% of the cells in Cre drivers, leading to only a handful cell types, typically 2–3, remaining in the intersection. Cre/Flp combinatorial mouse lines enabled us to identify and anatomically characterize retinal cell types with greater ease and demonstrated the feasibility of intersectional strategies in retinal research. In addition to the retina, we examined Flp expression in the lateral geniculate nucleus and superior colliculus. Our results establish a foundation for future application of intersectional strategies in the retina and retino-recipient regions.
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Affiliation(s)
- Andrew Jo
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Jian Xu
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Sercan Deniz
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Suraj Cherian
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Steven H DeVries
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Yongling Zhu
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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14
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Fan HF, Ma CH, Jayaram M. Single-Molecule Tethered Particle Motion: Stepwise Analyses of Site-Specific DNA Recombination. Micromachines (Basel) 2018; 9:E216. [PMID: 30424148 PMCID: PMC6187709 DOI: 10.3390/mi9050216] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/25/2018] [Accepted: 04/28/2018] [Indexed: 12/17/2022]
Abstract
Tethered particle motion/microscopy (TPM) is a biophysical tool used to analyze changes in the effective length of a polymer, tethered at one end, under changing conditions. The tether length is measured indirectly by recording the Brownian motion amplitude of a bead attached to the other end. In the biological realm, DNA, whose interactions with proteins are often accompanied by apparent or real changes in length, has almost exclusively been the subject of TPM studies. TPM has been employed to study DNA bending, looping and wrapping, DNA compaction, high-order DNA⁻protein assembly, and protein translocation along DNA. Our TPM analyses have focused on tyrosine and serine site-specific recombinases. Their pre-chemical interactions with DNA cause reversible changes in DNA length, detectable by TPM. The chemical steps of recombination, depending on the substrate and the type of recombinase, may result in a permanent length change. Single molecule TPM time traces provide thermodynamic and kinetic information on each step of the recombination pathway. They reveal how mechanistically related recombinases may differ in their early commitment to recombination, reversibility of individual steps, and in the rate-limiting step of the reaction. They shed light on the pre-chemical roles of catalytic residues, and on the mechanisms by which accessory proteins regulate recombination directionality.
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Affiliation(s)
- Hsiu-Fang Fan
- Biophotonics and Molecular Imaging Center, Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan.
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan.
| | - Chien-Hui Ma
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
| | - Makkuni Jayaram
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
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15
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Jensen IS, Inui K, Drakulic S, Jayaprakash S, Sander B, Golas MM. Expression of Flp Protein in a Baculovirus/Insect Cell System for Biotechnological Applications. Protein J 2017; 36:332-342. [PMID: 28660316 DOI: 10.1007/s10930-017-9724-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The Saccharomyces cerevisiae Flp protein is a site-specific recombinase that recognizes and binds to the Flp recognition target (FRT) site, a specific sequence comprised of at least two inverted repeats separated by a spacer. Binding of four monomers of Flp is required to mediate recombination between two FRT sites. Because of its site-specific cleavage characteristics, Flp has been established as a genome engineering tool. Amongst others, Flp is used to direct insertion of genes of interest into eukaryotic cells based on single and double FRT sites. A Flp-encoding plasmid is thereby typically cotransfected with an FRT-harboring donor plasmid. Moreover, Flp can be used to excise DNA sequences that are flanked by FRT sites. Therefore, the aim of this study was to determine whether Flp protein and its step-arrest mutant, FlpH305L, recombinantly expressed in insect cells, can be used for biotechnological applications. Using a baculovirus system, the proteins were expressed as C-terminally 3 × FLAG-tagged proteins and were purified by anti-FLAG affinity selection. As demonstrated by electrophoretic mobility shift assays (EMSAs), purified Flp and FlpH305L bind to FRT-containing DNA. Furthermore, using a cell assay, purified Flp was shown to be active in recombination and to mediate efficient insertion of a donor plasmid into the genome of target cells. Thus, these proteins can be used for applications such as DNA-binding assays, in vitro recombination, or genome engineering.
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Affiliation(s)
- Ida S Jensen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Ken Inui
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Srdja Drakulic
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Sakthidasan Jayaprakash
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Bjoern Sander
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark.
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16
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Abstract
Recombinase-mediated cassette exchange, or RMCE, is a genome engineering tool that can be used to swap DNA fragments of interest between two DNA molecules. In a variation of RMCE, called dual RMCE, the exchange of DNA fragments is mediated by two recombinases in contrast to one recombinase in the classic RMCE reaction. Under optimal conditions, the efficiency of dual RMCE can be quite high: up to ~45% of the transfected cells depending on the recombinase pair used to mediate the replacement reaction. Here we describe protocols for preparing for, performing, and optimizing the parameters of dual RMCE.
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Affiliation(s)
- Eugenia Voziyanova
- School of Biosciences, Louisiana Tech University, 1 Adams Blvd, Ruston, LA, 71272, USA
| | - Rachelle P Anderson
- School of Biosciences, Louisiana Tech University, 1 Adams Blvd, Ruston, LA, 71272, USA
| | - Yuri Voziyanov
- School of Biosciences, Louisiana Tech University, 1 Adams Blvd, Ruston, LA, 71272, USA.
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17
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Plummer NW, Evsyukova IY, Robertson SD, de Marchena J, Tucker CJ, Jensen P. Expanding the power of recombinase-based labeling to uncover cellular diversity. Development 2015; 142:4385-93. [PMID: 26586220 DOI: 10.1242/dev.129981] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/09/2015] [Indexed: 12/20/2022]
Abstract
Investigating the developmental, structural and functional complexity of mammalian tissues and organs depends on identifying and gaining experimental access to diverse cell populations. Here, we describe a set of recombinase-responsive fluorescent indicator alleles in mice that significantly extends our ability to uncover cellular diversity by exploiting the intrinsic genetic signatures that uniquely define cell types. Using a recombinase-based intersectional strategy, these new alleles uniquely permit non-invasive labeling of cells defined by the overlap of up to three distinct gene expression domains. In response to different combinations of Cre, Flp and Dre recombinases, they express eGFP and/or tdTomato to allow the visualization of full cellular morphology. Here, we demonstrate the value of these features through a proof-of-principle analysis of the central noradrenergic system. We label previously inaccessible subpopulations of noradrenergic neurons to reveal details of their three-dimensional architecture and axon projection profiles. These new indicator alleles will provide experimental access to cell populations at unprecedented resolution, facilitating analysis of their developmental origin and anatomical, molecular and physiological properties.
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Affiliation(s)
- Nicholas W Plummer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Irina Y Evsyukova
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Sabrina D Robertson
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Jacqueline de Marchena
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Charles J Tucker
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Patricia Jensen
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
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18
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Shah R, Li F, Voziyanova E, Voziyanov Y. Target-specific variants of Flp recombinase mediate genome engineering reactions in mammalian cells. FEBS J 2015; 282:3323-33. [PMID: 26077105 DOI: 10.1111/febs.13345] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/18/2015] [Accepted: 06/12/2015] [Indexed: 12/30/2022]
Abstract
Genome engineering relies on DNA-modifying enzymes that are able to locate a DNA sequence of interest and initiate a desired genome rearrangement. Currently, the field predominantly utilizes site-specific DNA nucleases that depend on the host DNA repair machinery to complete a genome modification task. We show here that genome engineering approaches that employ target-specific variants of the self-sufficient, versatile site-specific DNA recombinase Flp can be developed into promising alternatives. We demonstrate that the Flp variant evolved to recombine an FRT-like sequence, FL-IL10A, which is located upstream of the human interleukin-10 gene, and can target this sequence in the model setting of Chinese hamster ovary and human embryonic kidney 293 cells. This target-specific Flp variant is able to perform the integration reaction and, when paired with another recombinase, the dual recombinase-mediated cassette exchange reaction. The efficiency of the integration reaction in human cells can be enhanced by 'humanizing' the Flp variant gene and by adding the nuclear localization sequence to the recombinase.
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Affiliation(s)
- Riddhi Shah
- School of Biosciences, Louisiana Tech University, Ruston, LA, USA
| | - Feng Li
- School of Biosciences, Louisiana Tech University, Ruston, LA, USA
| | | | - Yuri Voziyanov
- School of Biosciences, Louisiana Tech University, Ruston, LA, USA
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