scholarly journals MITO-Tag Mice enable rapid isolation and multimodal profiling of mitochondria from specific cell types in vivo

2018 ◽  
Author(s):  
Erol Can Bayraktar ◽  
Lou Baudrier ◽  
Ceren Özerdem ◽  
Caroline A. Lewis ◽  
Sze Ham Chan ◽  
...  

ABSTRACTMitochondria are metabolic organelles that are essential for mammalian life, but the dynamics of mitochondrial metabolism within mammalian tissues in vivo remains incompletely understood. While whole-tissue metabolite profiling has been useful for studying metabolism in vivo, such an approach lacks resolution at the cellular and subcellular level. In vivo methods for interrogating organellar metabolites in specific cell-types within mammalian tissues have been limited. To address this, we built on prior work in which we exploited a mitochondrially-localized 3XHA epitope-tag (“MITO-Tag”) for the fast isolation of mitochondria from cultured cells to now generate “MITO-Tag Mice.” Affording spatiotemporal control over MITO-Tag expression, these transgenic animals enable the rapid, cell-type-specific immunoisolation of mitochondria from tissues, which we verified using a combination of proteomic and metabolomic approaches. Using MITO-Tag Mice and targeted and untargeted metabolite profiling, we identified changes during fasted and refed conditions in a diverse array of mitochondrial metabolites in hepatocytes and found metabolites that behaved differently at the mitochondrial versus whole-tissue level. MITO-Tag Mice should have utility for studying mitochondrial physiology and our strategy should be generally applicable for studying other mammalian organelles in specific cell-types in vivo.

2018 ◽  
Vol 116 (1) ◽  
pp. 303-312 ◽  
Author(s):  
Erol C. Bayraktar ◽  
Lou Baudrier ◽  
Ceren Özerdem ◽  
Caroline A. Lewis ◽  
Sze Ham Chan ◽  
...  

Mitochondria are metabolic organelles that are essential for mammalian life, but the dynamics of mitochondrial metabolism within mammalian tissues in vivo remains incompletely understood. While whole-tissue metabolite profiling has been useful for studying metabolism in vivo, such an approach lacks resolution at the cellular and subcellular level. In vivo methods for interrogating organellar metabolites in specific cell types within mammalian tissues have been limited. To address this, we built on prior work in which we exploited a mitochondrially localized 3XHA epitope tag (MITO-Tag) for the fast isolation of mitochondria from cultured cells to generate MITO-Tag Mice. Affording spatiotemporal control over MITO-Tag expression, these transgenic animals enable the rapid, cell-type-specific immunoisolation of mitochondria from tissues, which we verified using a combination of proteomic and metabolomic approaches. Using MITO-Tag Mice and targeted and untargeted metabolite profiling, we identified changes during fasted and refed conditions in a diverse array of mitochondrial metabolites in hepatocytes and found metabolites that behaved differently at the mitochondrial versus whole-tissue level. MITO-Tag Mice should have utility for studying mitochondrial physiology, and our strategy should be generally applicable for studying other mammalian organelles in specific cell types in vivo.


1993 ◽  
Vol 105 (4) ◽  
pp. 1025-1043 ◽  
Author(s):  
M. Berryman ◽  
Z. Franck ◽  
A. Bretscher

Ezrin and moesin are two cytoskeletal proteins originally purified from human placenta that are 74% identical in overall protein sequence. They are believed to be membrane-cytoskeletal linking proteins because they share sequence homology with erythrocyte band 4.1 and colocalize with actin specifically in microvilli and membrane ruffles in cultured cells. To determine if ezrin and moesin share similar distributions in vivo, we studied their localizations with respect to F-actin in tissue sections. Surprisingly, ezrin and moesin exhibited very different cellular distributions. Ezrin was highly concentrated and colocalized with actin on the apical surface of many epithelial cell types. During enterocyte differentiation, the pattern of expression and redistribution of ezrin was consistent with it performing a role in microvillus assembly. Immunoelectron microscopy in differentiated cells revealed that ezrin was restricted mainly to the plasma membrane of microvilli and other actin-rich surface projections. Moesin was found in endothelial cells and was also enriched in the apical microvilli of a restricted set of epithelial cells. All polarized cell types with abundant microvilli contained one or both proteins, suggesting that ezrin and moesin perform related functions. However, the differential expression of ezrin and moesin indicates that they have distinct properties, which are uniquely adapted to specific cell types.


2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Wenqing Jean Lee ◽  
Sumantra Chatterjee ◽  
Sook Peng Yap ◽  
Siew Lan Lim ◽  
Xing Xing ◽  
...  

Embryogenesis is an intricate process involving multiple genes and pathways. Some of the key transcription factors controlling specific cell types are the Sox trio, namely, Sox5, Sox6, and Sox9, which play crucial roles in organogenesis working in a concerted manner. Much however still needs to be learned about their combinatorial roles during this process. A developmental genomics and systems biology approach offers to complement the reductionist methodology of current developmental biology and provide a more comprehensive and integrated view of the interrelationships of complex regulatory networks that occur during organogenesis. By combining cell type-specific transcriptome analysis and in vivo ChIP-Seq of the Sox trio using mouse embryos, we provide evidence for the direct control of Sox5 and Sox6 by the transcriptional trio in the murine model and by Morpholino knockdown in zebrafish and demonstrate the novel role of Tgfb2, Fbxl18, and Tle3 in formation of Sox5, Sox6, and Sox9 dependent tissues. Concurrently, a complete embryonic gene regulatory network has been generated, identifying a wide repertoire of genes involved and controlled by the Sox trio in the intricate process of normal embryogenesis.


2007 ◽  
Vol 81 (16) ◽  
pp. 8656-8665 ◽  
Author(s):  
Fulvia Terenzi ◽  
Christine White ◽  
Srabani Pal ◽  
Bryan R. G. Williams ◽  
Ganes C. Sen

ABSTRACT The interferon-stimulated genes (ISGs) ISG56 and ISG54 are strongly induced in cultured cells by type I interferons (IFNs), viruses, and double-stranded RNA (dsRNA), which activate their transcription by various signaling pathways. Here we studied the stimulus-dependent induction of both genes in vivo. dsRNA, which is generated during virus infection, induced the expression of both genes in all organs examined. Induction was not seen in STAT1-deficient mice, indicating that dsRNA-induced gene expression requires endogenous IFN. We further examined the regulation of these ISGs in several organs from mice injected with dsRNA or IFN-β. Both ISG56 and ISG54 were widely expressed and at comparable levels. However, in organs isolated from mice injected with IFN-α the expression of ISG54 was reduced and more restricted in distribution compared with the expression level and distribution of ISG56. When we began to study specific cell types, splenic B cells showed ISG54 but not ISG56 expression in response to all agonists. Finally, in livers isolated from mice infected with vesicular stomatitis virus, the expression of ISG56, but not ISG54, was induced; this difference was observed at both protein and mRNA levels. These studies have revealed unexpected complexity in IFN-stimulated gene induction in vivo. For the first time we showed that the two closely related genes are expressed in a tissue-specific and inducer-specific manner. Furthermore, our findings provide the first evidence of a differential pattern of expression of ISG54 and ISG56 genes by IFN-α and IFN-β.


2017 ◽  
Author(s):  
Mari Mito ◽  
Mitsutaka Kadota ◽  
Kaori Tanaka ◽  
Yasuhide Furuta ◽  
Kuniya Abe ◽  
...  

AbstractBackgroundThe nervous system of higher eukaryotes is composed of numerous types of neurons and glia that together orchestrate complex neuronal responses. However, this complex pool of cells typically poses analytical challenges in investigating gene expression profiles and their epigenetic basis for specific cell types. Here, we developed a novel method that enables cell type-specific analyses of epigenetic modifications using tandem chromatin immunoprecipitation sequencing (tChIP-Seq).ResultsFLAG-tagged histone H2B, a constitutive chromatin component, was first expressed in Camk2a-positive pyramidal cortical neurons and used to purify chromatin in a cell type-specific manner. Subsequent chromatin immunoprecipitation using antibodies against H3K4me3—an active promoter mark—allowed us to survey neuron-specific coding and non-coding transcripts. Indeed, tChIP-Seq identified hundreds of genes associated with neuronal functions and genes with unknown functions expressed in cortical neurons.ConclusionstChIP-Seq thus provides a versatile approach to investigating the epigenetic modifications of particular cell types in vivo.


2021 ◽  
Vol 22 (10) ◽  
pp. 5335
Author(s):  
Monika Chanu Chongtham ◽  
Tamer Butto ◽  
Kanak Mungikar ◽  
Susanne Gerber ◽  
Jennifer Winter

Increasing numbers of studies seek to characterize the different cellular sub-populations present in mammalian tissues. The techniques “Isolation of Nuclei Tagged in Specific Cell Types” (INTACT) or “Fluorescence-Activated Nuclei Sorting” (FANS) are frequently used for isolating nuclei of specific cellular subtypes. These nuclei are then used for molecular characterization of the cellular sub-populations. Despite the increasing popularity of both techniques, little is known about their isolation efficiency, advantages, and disadvantages or downstream molecular effects. In our study, we compared the physical and molecular attributes of sfGFP+ nuclei isolated by the two methods—INTACT and FANS—from the neocortices of Arc-CreERT2 × CAG-Sun1/sfGFP animals. We identified differences in efficiency of sfGFP+ nuclei isolation, nuclear size as well as transcriptional (RNA-seq) and chromatin accessibility (ATAC-seq) states. Therefore, our study presents a comprehensive comparison between the two widely used nuclei sorting techniques, identifying the advantages and disadvantages for both INTACT and FANS. Our conclusions are summarized in a table to guide researchers in selecting the most suitable methodology for their individual experimental design.


2018 ◽  
Author(s):  
Scott J. Callahan ◽  
Stephanie Tepan ◽  
Yan M Zhang ◽  
Helen Lindsay ◽  
Alexa Burger ◽  
...  

AbstractTransgenic animals are invaluable for modeling cancer genomics, but often require complex crosses of multiple germline alleles to obtain the desired combinations. Zebrafish models have advantages in that transgenes can be rapidly tested by mosaic expression, but these typically lack spatial and temporal control of tumor onset, which limits their utility for the study of tumor progression and metastasis. To overcome these limitations, we have developed a method called Transgene Electroporation in Adult Zebrafish (TEAZ). TEAZ can deliver DNA constructs with promoter elements of interest to drive fluorophores, oncogenes, or CRISPR-Cas9-based mutagenic cassettes in specific cell types. Using TEAZ, we created a highly aggressive melanoma model by expression of BRAFV600Ein spatially constrained melanocytes in the context of p53 deficiency and Cas9-mediated inactivation of Rb1. Unlike prior models that take ~4 months to develop, we found that TEAZ leads to tumor onset in ~7 weeks and these develop in fully immunocompetent animals. As the resulting tumors initiated at highly defined locations, we could track their progression via fluorescence and documented deep invasion into tissues and metastatic deposits. TEAZ can be deployed to other tissues and cell types such as the heart with the use of suitable transgenic promoters. The versatility of TEAZ makes it widely accessible for rapid modeling of somatic gene alterations and cancer progression at a scale not achievable in other in vivo systems.


eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Alexander M Herman ◽  
Longwen Huang ◽  
Dona K Murphey ◽  
Isabella Garcia ◽  
Benjamin R Arenkiel

Channelrhodopsin-2 (ChR2) has quickly gained popularity as a powerful tool for eliciting genetically targeted neuronal activation. However, little has been reported on the response kinetics of optogenetic stimulation across different neuronal subtypes. With excess stimulation, neurons can be driven into depolarization block, a state where they cease to fire action potentials. Herein, we demonstrate that light-induced depolarization block in neurons expressing ChR2 poses experimental challenges for stable activation of specific cell types and may confound interpretation of experiments when ‘activated’ neurons are in fact being functionally silenced. We show both ex vivo and in vivo that certain neuronal subtypes targeted for ChR2 expression become increasingly susceptible to depolarization block as the duration of light pulses are increased. We find that interneuron populations have a greater susceptibility to this effect than principal excitatory neurons, which are more resistant to light-induced depolarization block. Our results highlight the need to empirically determine the photo-response properties of targeted neurons when using ChR2, particularly in studies designed to elicit complex circuit responses in vivo where neuronal activity will not be recorded simultaneous to light stimulation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Lucia Barra ◽  
Pasquale Termolino ◽  
Riccardo Aiese Cigliano ◽  
Gaetana Cremona ◽  
Rosa Paparo ◽  
...  

Isolation of nuclei tagged in specific cell types (INTACT) is a method developed to isolate cell-type-specific nuclei that are tagged through in vivo biotin labeling of a nuclear targeting fusion (NTF) protein. In our work, INTACT was used to capture nuclei of meiocytes and to generate a meiotic transcriptome in Arabidopsis. Using the promoter of AtDMC1 recombinase to label meiotic nuclei, we generated transgenic plants carrying AtDMC1:NTF along with biotin ligase enzyme (BirA) under the constitutive ACTIN2 (ACT2) promoter. AtDMC1-driven expression of biotin-labeled NTF allowed us to collect nuclei of meiocytes by streptavidin-coated magnetic beads. The nuclear meiotic transcriptome was obtained by RNA-seq using low-quantity input RNA. Transcripts grouped into different categories according to their expression levels were investigated by gene ontology enrichment analysis (GOEA). The most enriched GO term “DNA demethylation” in mid/high-expression classes suggests that this biological process is particularly relevant to meiosis onset. The majority of genes with established roles in meiosis were distributed in the classes of mid/high and high expression. Meiotic transcriptome was compared with public available transcriptomes from other tissues in Arabidopsis. Bioinformatics analysis by expression network identified a core of more than 1,500 genes related to meiosis landmarks.


2018 ◽  
Vol 18 (4) ◽  
pp. 246-255 ◽  
Author(s):  
Lara Termini ◽  
Enrique Boccardo

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.


Sign in / Sign up

Export Citation Format

Share Document