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Zhu X, Yang Y, Feng D, Wang O, Chen J, Wang J, Wang B, Liu Y, Edenfield BH, Haddock AN, Wang Y, Patel T, Bi Y, Ji B. Albumin promoter-driven FlpO expression induces efficient genetic recombination in mouse liver. Am J Physiol Gastrointest Liver Physiol 2024; 326:G495-G503. [PMID: 38469630 DOI: 10.1152/ajpgi.00263.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 03/13/2024]
Abstract
Tissue-specific gene manipulations are widely used in genetically engineered mouse models. A single recombinase system, such as the one using Alb-Cre, has been commonly used for liver-specific genetic manipulations. However, most diseases are complex, involving multiple genetic changes and various cell types. A dual recombinase system is required for conditionally modifying different genes sequentially in the same cell or inducing genetic changes in different cell types within the same organism. A FlpO cDNA was inserted between the last exon and 3'-UTR of the mouse albumin gene in a bacterial artificial chromosome (BAC-Alb-FlpO). The founders were crossed with various reporter mice to examine the efficiency of recombination. Liver cancer tumorigenesis was investigated by crossing the FlpO mice with FSF-KrasG12D mice and p53frt mice (KPF mice). BAC-Alb-FlpO mice exhibited highly efficient recombination capability in both hepatocytes and intrahepatic cholangiocytes. No recombination was observed in the duodenum and pancreatic cells. BAC-Alb-FlpO-mediated liver-specific expression of mutant KrasG12D and conditional deletion of p53 gene caused the development of liver cancer. Remarkably, liver cancer in these KPF mice manifested a distinctive mixed hepatocellular carcinoma and cholangiocarcinoma phenotype. A highly efficient and liver-specific BAC-Alb-FlpO mouse model was developed. In combination with other Cre lines, different genes can be manipulated sequentially in the same cell, or distinct genetic changes can be induced in different cell types of the same organism.NEW & NOTEWORTHY A liver-specific Alb-FlpO mouse line was generated. By coupling it with other existing CreERT or Cre lines, the dual recombinase approach can enable sequential gene modifications within the same cell or across various cell types in an organism for liver research through temporal and spatial gene manipulations.
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Affiliation(s)
- Xiaohui Zhu
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Yan Yang
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Dongfeng Feng
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Oliver Wang
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Jiaxiang Chen
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Jiale Wang
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Bin Wang
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Yang Liu
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Brandy H Edenfield
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Ashley N Haddock
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
| | - Ying Wang
- Departments of Cardiovascular Diseases and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States
| | - Tushar Patel
- Department of Transplantation, Mayo Clinic, Jacksonville, Florida, United States
| | - Yan Bi
- Department of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, Florida, United States
| | - Baoan Ji
- Department of Cancer Biology, Mayo Clinic, Jacksonville, Florida, United States
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2
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Wang Z, Chen C, Ge X. Large T antigen mediated target gene replication improves site-specific recombination efficiency. Front Bioeng Biotechnol 2024; 12:1377167. [PMID: 38737535 PMCID: PMC11082406 DOI: 10.3389/fbioe.2024.1377167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/11/2024] [Indexed: 05/14/2024] Open
Abstract
With advantages of high-fidelity, monoclonality and large cargo capacity, site-specific recombination (SSR) holds great promises for precise genomic modifications. However, broad applications of SSR have been hurdled by low integration efficiency, and the amount of donor DNA available in nucleus for SSR presents as a limiting factor. Inspired by the DNA replication mechanisms observed in double-stranded DNA virus SV40, we hypothesized that expression of SV40 large T antigen (TAg) can increase the copy number of the donor plasmid bearing an SV40 origin, and in consequence promote recombination events. This hypothesis was tested with dual recombinase-mediated cassette exchange (RMCE) in suspension 293F cells. Results showed that TAg co-transfection significantly enhanced SSR in polyclonal cells. In the monoclonal cell line carrying a single landing pad at an identified genomic locus, 12% RMCE efficiency was achieved, and such improvement was indeed correlated with donor plasmid amplification. The developed TAg facilitated RMCE (T-RMCE) was exploited for the construction of large libraries of >107 diversity, from which GFP variants with enhanced fluorescence were isolated. We expect the underlying principle of target gene amplification can be applicable to other SSR processes and gene editing approaches in general for directed evolution and large-scale genomic screening in mammalian cells.
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Affiliation(s)
- Zening Wang
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA, United States
| | - Chuan Chen
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA, United States
| | - Xin Ge
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA, United States
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3
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Chen C, Wang Z, Kang M, Lee KB, Ge X. High-fidelity large-diversity monoclonal mammalian cell libraries by cell cycle arrested recombinase-mediated cassette exchange. Nucleic Acids Res 2023; 51:e113. [PMID: 37941133 PMCID: PMC10711435 DOI: 10.1093/nar/gkad1001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 09/26/2023] [Accepted: 10/18/2023] [Indexed: 11/10/2023] Open
Abstract
Mammalian cells carrying defined genetic variations have shown great potentials in both fundamental research and therapeutic development. However, their full use was limited by lack of a robust method to construct large monoclonal high-quality combinatorial libraries. This study developed cell cycle arrested recombinase-mediated cassette exchange (aRMCE), able to provide monoclonality, precise genomic integration and uniform transgene expression. Via optimized nocodazole-mediated mitotic arrest, 20% target gene replacement efficiency was achieved without antibiotic selection, and the improved aRMCE efficiency was applicable to a variety of tested cell clones, transgene targets and transfection methods. As a demonstration of this versatile method, we performed directed evolution of fragment crystallizable (Fc), for which error-prone libraries of over 107 variants were constructed and displayed as IgG on surface of CHO cells. Diversities of constructed libraries were validated by deep sequencing, and panels of novel Fc mutants were identified showing improved binding towards specific Fc gamma receptors and enhanced effector functions. Due to its large cargo capacity and compatibility with different mutagenesis approaches, we expect this mammalian cell platform technology has broad applications for directed evolution, multiplex genetic assays, cell line development and stem cell engineering.
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Affiliation(s)
- Chuan Chen
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, USA
| | - Zening Wang
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, USA
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Minhyo Kang
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, USA
| | - Ki Baek Lee
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Xin Ge
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, USA
- Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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4
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Maes S, Deploey N, Peelman F, Eyckerman S. Deep mutational scanning of proteins in mammalian cells. CELL REPORTS METHODS 2023; 3:100641. [PMID: 37963462 PMCID: PMC10694495 DOI: 10.1016/j.crmeth.2023.100641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/06/2023] [Accepted: 10/20/2023] [Indexed: 11/16/2023]
Abstract
Protein mutagenesis is essential for unveiling the molecular mechanisms underlying protein function in health, disease, and evolution. In the past decade, deep mutational scanning methods have evolved to support the functional analysis of nearly all possible single-amino acid changes in a protein of interest. While historically these methods were developed in lower organisms such as E. coli and yeast, recent technological advancements have resulted in the increased use of mammalian cells, particularly for studying proteins involved in human disease. These advancements will aid significantly in the classification and interpretation of variants of unknown significance, which are being discovered at large scale due to the current surge in the use of whole-genome sequencing in clinical contexts. Here, we explore the experimental aspects of deep mutational scanning studies in mammalian cells and report the different methods used in each step of the workflow, ultimately providing a useful guide toward the design of such studies.
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Affiliation(s)
- Stefanie Maes
- VIB Center for Medical Biotechnology (CMB), Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Nick Deploey
- VIB Center for Medical Biotechnology (CMB), Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Frank Peelman
- VIB Center for Medical Biotechnology (CMB), Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium
| | - Sven Eyckerman
- VIB Center for Medical Biotechnology (CMB), Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, 9052 Ghent, Belgium.
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5
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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] [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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6
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Law NC. Lineage Tracing of Spermatogonial Stem Cells Within the Male Germline. Methods Mol Biol 2023; 2656:309-324. [PMID: 37249878 DOI: 10.1007/978-1-0716-3139-3_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Spermatogonial stem cells (SSCs) are the fundamental units from which continuous spermatogenesis arises. Although our knowledge regarding the basic properties of SSCs has grown, driven primarily through the advancement of techniques and technologies to study SSCs, the mechanisms controlling their fate remain largely unknown. Among the modern strategies to evaluate SSCs, lineage tracing is among the few established approaches that allow for functional assessment of stem cell capacity. As a result, lineage tracing continues to forge new discoveries underlying the basic attributes of SSCs as well as the molecular factors that govern SSC function. Traditional approaches to lineage tracing with dyes or radioactive labels suffer from progressive loss after successive cell divisions or unintentional label transfer to neighboring cells. To address these limitations, genetic approaches primarily leveraging transgenic technologies have prevailed as the preferred avenue for modern lineage tracing. This chapter will discuss current protocols for effective genetic lineage tracing and address applications of this technology, considerations when designing lineage tracing experiments, and the methods involved in utilizing lineage tracing to study SSCs and other cell populations.
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Affiliation(s)
- Nathan C Law
- Center for Reproductive Biology, Department of Animal Sciences, College of Agricultural, Human, and Natural Resource Sciences, Washington State University, Pullman, WA, USA.
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7
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Lane AR, Cogdell IC, Jessell TM, Bikoff JB, Alvarez FJ. Genetic targeting of adult Renshaw cells using a Calbindin 1 destabilized Cre allele for intersection with Parvalbumin or Engrailed1. Sci Rep 2021; 11:19861. [PMID: 34615947 PMCID: PMC8494874 DOI: 10.1038/s41598-021-99333-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 09/16/2021] [Indexed: 11/09/2022] Open
Abstract
Renshaw cells (RCs) are one of the most studied spinal interneurons; however, their roles in motor control remain enigmatic in part due to the lack of experimental models to interfere with RC function, specifically in adults. To overcome this limitation, we leveraged the distinct temporal regulation of Calbindin (Calb1) expression in RCs to create genetic models for timed RC manipulation. We used a Calb1 allele expressing a destabilized Cre (dgCre) theoretically active only upon trimethoprim (TMP) administration. TMP timing and dose influenced RC targeting efficiency, which was highest within the first three postnatal weeks, but specificity was low with many other spinal neurons also targeted. In addition, dgCre showed TMP-independent activity resulting in spontaneous recombination events that accumulated with age. Combining Calb1-dgCre with Parvalbumin (Pvalb) or Engrailed1 (En1) Flpo alleles in dual conditional systems increased cellular and timing specificity. Under optimal conditions, Calb1-dgCre/Pvalb-Flpo mice targeted 90% of RCs and few dorsal horn neurons; Calb1-dgCre/En1-Flpo mice showed higher specificity, but only a maximum of 70% of RCs targeted. Both models targeted neurons throughout the brain. Restricted spinal expression was obtained by injecting intraspinally AAVs carrying dual conditional genes. These results describe the first models to genetically target RCs bypassing development.
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Affiliation(s)
- Alicia R Lane
- Department of Physiology, Emory University, Atlanta, GA, 30322, USA
| | | | - Thomas M Jessell
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Jay B Bikoff
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
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8
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Feary M, Moffat MA, Casperson GF, Allen MJ, Young RJ. CHOK1SV GS-KO SSI expression system: A combination of the Fer1L4 locus and glutamine synthetase selection. Biotechnol Prog 2021; 37:e3137. [PMID: 33609084 DOI: 10.1002/btpr.3137] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/03/2021] [Accepted: 02/07/2021] [Indexed: 12/11/2022]
Abstract
There are an ever-increasing number of biopharmaceutical candidates in clinical trials fueling an urgent need to streamline the cell line development process. A critical part of the process is the methodology used to generate and screen candidate cell lines compatible with GMP manufacturing processes. The relatively large amount of clone phenotypic variation observed from conventional "random integration" (RI)-based cell line construction is thought to be the result of a combination of the position variegation effect, genome plasticity and clonal variation. Site-specific integration (SSI) has been used by several groups to temper the influence of the position variegation effect and thus reduce variability in expression of biopharmaceutical candidates. Following on from our previous reports on the application of the Fer1L4 locus for SSI in CHOK1SV (10E9), we have combined this locus and a CHOK1SV glutamine synthetase knockout (GS-KO) host to create an improved expression system. The host, CHOK1SV GS-KO SSI (HD7876), was created by homology directed integration of a targetable landing pad flanked with incompatible Frt sequences in the Fer1L4 gene. The targeting vector contains a promoterless GS expression cassette and monoclonal antibody (mAb) expression cassettes, flanked by Frt sites compatible with equivalent sites flanking the landing pad in the host cell line. SSI clones expressing four antibody candidates, selected in a streamlined cell line development process, have mAb titers which rival RI (1.0-4.5 g/L) and robust expression stability (100% of clones stable through the 50 generation "manufacturing window" which supports commercial manufacturing at 12,000 L bioreactor scale).
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Affiliation(s)
- Marc Feary
- R&D Cell Engineering, Lonza Biologics, Little Chesterford, UK
| | - Mark A Moffat
- Cell Line Development, Biotherapeutics Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, 63017, USA
| | - Gerald F Casperson
- Cell Line Development, Biotherapeutics Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, 63017, USA
| | - Martin J Allen
- Cell Line Development, Biotherapeutics Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, 63017, USA
| | - Robert J Young
- R&D Cell Engineering, Lonza Biologics, Little Chesterford, UK
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9
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Iwasaki S, Iwasaki W, Takahashi M, Sakamoto A, Watanabe C, Shichino Y, Floor SN, Fujiwara K, Mito M, Dodo K, Sodeoka M, Imataka H, Honma T, Fukuzawa K, Ito T, Ingolia NT. The Translation Inhibitor Rocaglamide Targets a Bimolecular Cavity between eIF4A and Polypurine RNA. Mol Cell 2019; 73:738-748.e9. [PMID: 30595437 PMCID: PMC6386617 DOI: 10.1016/j.molcel.2018.11.026] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 07/23/2018] [Accepted: 11/15/2018] [Indexed: 01/17/2023]
Abstract
A class of translation inhibitors, exemplified by the natural product rocaglamide A (RocA), isolated from Aglaia genus plants, exhibits antitumor activity by clamping eukaryotic translation initiation factor 4A (eIF4A) onto polypurine sequences in mRNAs. This unusual inhibitory mechanism raises the question of how the drug imposes sequence selectivity onto a general translation factor. Here, we determined the crystal structure of the human eIF4A1⋅ATP analog⋅RocA⋅polypurine RNA complex. RocA targets the "bi-molecular cavity" formed characteristically by eIF4A1 and a sharply bent pair of consecutive purines in the RNA. Natural amino acid substitutions found in Aglaia eIF4As changed the cavity shape, leading to RocA resistance. This study provides an example of an RNA-sequence-selective interfacial inhibitor fitting into the space shaped cooperatively by protein and RNA with specific sequences.
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Affiliation(s)
- Shintaro Iwasaki
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo 277-8561, Japan.
| | - Wakana Iwasaki
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan; Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Mari Takahashi
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan; Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Ayako Sakamoto
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan; Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Chiduru Watanabe
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Tsurumi-ku, Yokohama 230-0045, Japan; Laboratory for Structure-Based Molecular Design, RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Yuichi Shichino
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Stephen N Floor
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Koichi Fujiwara
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Mari Mito
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Kosuke Dodo
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan; AMED-CREST, Japan Agency for Medical Research and Development, Wako, Saitama 351-0198, Japan; RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
| | - Mikiko Sodeoka
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan; AMED-CREST, Japan Agency for Medical Research and Development, Wako, Saitama 351-0198, Japan; RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
| | - Hiroaki Imataka
- Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2201, Japan
| | - Teruki Honma
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Tsurumi-ku, Yokohama 230-0045, Japan; Laboratory for Structure-Based Molecular Design, RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Kaori Fukuzawa
- School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo 142-8501, Japan
| | - Takuhiro Ito
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama 230-0045, Japan; Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, Tsurumi-ku, Yokohama 230-0045, Japan.
| | - Nicholas T Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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A single reporter mouse line for Vika, Flp, Dre, and Cre-recombination. Sci Rep 2018; 8:14453. [PMID: 30262904 PMCID: PMC6160450 DOI: 10.1038/s41598-018-32802-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 09/13/2018] [Indexed: 11/28/2022] Open
Abstract
Site-specific recombinases (SSR) are utilized as important genome engineering tools to precisely modify the genome of mice and other model organisms. Reporter mice that mark cells that at any given time had expressed the enzyme are frequently used for lineage tracing and to characterize newly generated mice expressing a recombinase from a chosen promoter. With increasing sophistication of genome alteration strategies, the demand for novel SSR systems that efficiently and specifically recombine their targets is rising and several SSR-systems are now used in combination to address complex biological questions in vivo. Generation of reporter mice for each one of these recombinases is cumbersome and increases the number of mouse lines that need to be maintained in animal facilities. Here we present a multi-reporter mouse line for loci-of-recombination (X) (MuX) that streamlines the characterization of mice expressing prominent recombinases. MuX mice constitutively express nuclear green fluorescent protein after recombination by either Cre, Flp, Dre or Vika recombinase, rationalizing the number of animal lines that need to be maintained. We also pioneer the use of the Vika/vox system in mice, illustrating its high efficacy and specificity, thereby facilitating future designs of sophisticated recombinase-based in vivo genome engineering strategies.
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11
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Yu J, Zanotti S, Schilling L, Canalis E. Nuclear factor of activated T cells 2 is required for osteoclast differentiation and function in vitro but not in vivo. J Cell Biochem 2018; 119:9334-9345. [PMID: 30010214 DOI: 10.1002/jcb.27212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 05/30/2018] [Indexed: 01/09/2023]
Abstract
Nuclear factor of activated T cells (NFAT) c2 is important for the immune response and it compensates for NFATc1 for its effects on osteoclastogenesis, but its role in this process is not established. To study the function of NFATc2 in the skeleton, Nfatc2loxP/loxP mice, where the Nfact2 exon 2 is flanked by loxP sequences, were created and mated with mice expressing the Cre recombinase under the control of the Lyz2 promoter. Bone marrow-derived macrophage (BMM) from Lyz2Cre/WT ;Nfatc2Δ/Δ mice cultured in the presence of macrophage-colony stimulating factor and receptor activator of NF-κB ligand exhibited a decrease in the number and size of osteoclasts and a smaller sealing zone when compared to BMMs from Nfatc2loxP/loxP littermate controls. Bone resorption was decreased in osteoclasts from Lyz2Cre/WT ;Nfatc2Δ/Δ mice. This demonstrates that NFATc2 is necessary for optimal osteoclast maturation and function in vitro. Male and female Lyz2Cre/WT ;Nfatc2Δ/Δ mice did not exhibit an obvious skeletal phenotype by microcomputed tomography (μCT) at either 1 or 4 months of age when compared to Nfatc2loxP/loxP sex-matched littermates. Bone histomorphometry confirmed the μCT results, and conditional 4-month-old Lyz2Cre/WT ;Nfatc2Δ/Δ mice did not exhibit changes in parameters of bone histomorphometry. In conclusion, NFATc2 is necessary for optimal osteoclastogenesis in vitro, but its downregulation in the myeloid lineage has no consequences in skeletal remodeling in vivo.
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Affiliation(s)
- Jungeun Yu
- Department of Orthopaedic Surgery, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
| | - Stefano Zanotti
- Department of Orthopaedic Surgery, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
- Department of Medicine, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
| | - Lauren Schilling
- Department of Orthopaedic Surgery, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
| | - Ernesto Canalis
- Department of Orthopaedic Surgery, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
- Department of Medicine, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
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12
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Cold inducible promoter driven Cre-lox system proved to be highly efficient for marker gene excision in transgenic barley. J Biotechnol 2017; 265:15-24. [PMID: 29103986 DOI: 10.1016/j.jbiotec.2017.10.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 10/16/2017] [Accepted: 10/26/2017] [Indexed: 12/12/2022]
Abstract
A Cre-lox based auto-excision strategy has been adapted for barley, capable of cre and selectable marker gene (SMG) removal. The cold inducible wheat promoter called wcs120 was utilised for driving Cre expression. The binary vector was carrying the transgene (uidA) and a so called 'recombination cassette' flanked by the lox sequences. This part included both the recombinase gene and the SMG (bar) under the control of a constitutive promoter. T0, T1 and T2 transgenic plants were subjected to low temperature (at 4°C, 10°C and 12°C) at different developmental stages to induce recombination. The presence of uidA, cre, and bar genes and recombination footprints were studied by PCR and DNA sequencing, while cre transcription was followed by qRT-PCR. These analyses indicated that, cold treatment of the germinating seeds (4°C for 3days) followed by plant growing at higher temperature (24°C) has been the most efficient (90-100%), and this treatment lead to heritable changes in the genome. Thermal separation of Cre accumulation (at low temperature) from Cre enzyme activity (at higher temperature) could have prevented the premature excision of its own encoding gene, and lead to high expression level thereby increasing recombination frequency.
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Abstract
Systems metabolic engineering, which recently emerged as metabolic engineering integrated with systems biology, synthetic biology, and evolutionary engineering, allows engineering of microorganisms on a systemic level for the production of valuable chemicals far beyond its native capabilities. Here, we review the strategies for systems metabolic engineering and particularly its applications in Escherichia coli. First, we cover the various tools developed for genetic manipulation in E. coli to increase the production titers of desired chemicals. Next, we detail the strategies for systems metabolic engineering in E. coli, covering the engineering of the native metabolism, the expansion of metabolism with synthetic pathways, and the process engineering aspects undertaken to achieve higher production titers of desired chemicals. Finally, we examine a couple of notable products as case studies produced in E. coli strains developed by systems metabolic engineering. The large portfolio of chemical products successfully produced by engineered E. coli listed here demonstrates the sheer capacity of what can be envisioned and achieved with respect to microbial production of chemicals. Systems metabolic engineering is no longer in its infancy; it is now widely employed and is also positioned to further embrace next-generation interdisciplinary principles and innovation for its upgrade. Systems metabolic engineering will play increasingly important roles in developing industrial strains including E. coli that are capable of efficiently producing natural and nonnatural chemicals and materials from renewable nonfood biomass.
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14
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Togawa Y, Nunoshiba T, Hiratsu K. Cre/lox-based multiple markerless gene disruption in the genome of the extreme thermophile Thermus thermophilus. Mol Genet Genomics 2017; 293:277-291. [PMID: 28840320 DOI: 10.1007/s00438-017-1361-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/20/2017] [Indexed: 12/01/2022]
Abstract
Markerless gene-disruption technology is particularly useful for effective genetic analyses of Thermus thermophilus (T. thermophilus), which have a limited number of selectable markers. In an attempt to develop a novel system for the markerless disruption of genes in T. thermophilus, we applied a Cre/lox system to construct a triple gene disruptant. To achieve this, we constructed two genetic tools, a loxP-htk-loxP cassette and cre-expressing plasmid, pSH-Cre, for gene disruption and removal of the selectable marker by Cre-mediated recombination. We found that the Cre/lox system was compatible with the proliferation of the T. thermophilus HB27 strain at the lowest growth temperature (50 °C), and thus succeeded in establishing a triple gene disruptant, the (∆TTC1454::loxP, ∆TTC1535KpnI::loxP, ∆TTC1576::loxP) strain, without leaving behind a selectable marker. During the process of the sequential disruption of multiple genes, we observed the undesired deletion and inversion of the chromosomal region between multiple loxP sites that were induced by Cre-mediated recombination. Therefore, we examined the effects of a lox66-htk-lox71 cassette by exploiting the mutant lox sites, lox66 and lox71, instead of native loxP sites. We successfully constructed a (∆TTC1535::lox72, ∆TTC1537::lox72) double gene disruptant without inducing the undesired deletion of the 0.7-kbp region between the two directly oriented lox72 sites created by the Cre-mediated recombination of the lox66-htk-lox71 cassette. This is the first demonstration of a Cre/lox system being applicable to extreme thermophiles in a genetic manipulation. Our results indicate that this system is a powerful tool for multiple markerless gene disruption in T. thermophilus.
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Affiliation(s)
- Yoichiro Togawa
- Department of Applied Chemistry, National Defense Academy, Hashirimizu 1-10-20, Yokosuka, Kanagawa, 239-8686, Japan
| | - Tatsuo Nunoshiba
- College of Liberal Arts, International Christian University, Osawa 3-10-2, Mitaka, Tokyo, 181-8585, Japan
| | - Keiichiro Hiratsu
- Department of Applied Chemistry, National Defense Academy, Hashirimizu 1-10-20, Yokosuka, Kanagawa, 239-8686, Japan.
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15
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Muñoz-Jiménez C, Ayuso C, Dobrzynska A, Torres-Mendéz A, Ruiz PDLC, Askjaer P. An Efficient FLP-Based Toolkit for Spatiotemporal Control of Gene Expression in Caenorhabditis elegans. Genetics 2017; 206:1763-1778. [PMID: 28646043 PMCID: PMC5560786 DOI: 10.1534/genetics.117.201012] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/19/2017] [Indexed: 02/07/2023] Open
Abstract
Site-specific recombinases are potent tools to regulate gene expression. In particular, the Cre (cyclization recombination) and FLP (flipase) enzymes are widely used to either activate or inactivate genes in a precise spatiotemporal manner. Both recombinases work efficiently in the popular model organism Caenorhabditis elegans, but their use in this nematode is still only sporadic. To increase the utility of the FLP system in C. elegans, we have generated a series of single-copy transgenic strains that stably express an optimized version of FLP in specific tissues or by heat induction. We show that recombination efficiencies reach 100% in several cell types, such as muscles, intestine, and serotonin-producing neurons. Moreover, we demonstrate that most promoters drive recombination exclusively in the expected tissues. As examples of the potentials of the FLP lines, we describe novel tools for induced cell ablation by expression of the PEEL-1 toxin and a versatile FLP-out cassette for generation of GFP-tagged conditional knockout alleles. Together with other recombinase-based reagents created by the C. elegans community, this toolkit increases the possibilities for detailed analyses of specific biological processes at developmental stages inside intact animals.
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Affiliation(s)
- Celia Muñoz-Jiménez
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Cristina Ayuso
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Agnieszka Dobrzynska
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Antonio Torres-Mendéz
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Patricia de la Cruz Ruiz
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Peter Askjaer
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
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16
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Bowyer JE, Hsiao V, Wong WW, Bates DG. Mechanistic modelling of a recombinase‐based two‐input temporal logic gate. ENGINEERING BIOLOGY 2017. [DOI: 10.1049/enb.2017.0006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Affiliation(s)
- Jack E. Bowyer
- Warwick Integrative Synthetic Biology Centre, School of Engineering University of Warwick Coventry CV4 7AL UK
| | - Victoria Hsiao
- Biology and Biological Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Wilson W. Wong
- Department of Biomedical Engineering Boston University Boston MA 02215 USA
| | - Declan G. Bates
- Warwick Integrative Synthetic Biology Centre, School of Engineering University of Warwick Coventry CV4 7AL UK
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17
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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] [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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18
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Canalis E, Zanotti S. Hairy and Enhancer of Split-Related With YRPW Motif-Like (HeyL) Is Dispensable for Bone Remodeling in Mice. J Cell Biochem 2017; 118:1819-1826. [PMID: 28019674 DOI: 10.1002/jcb.25859] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 12/14/2022]
Abstract
Notch induces Hairy Enhancer of Split (Hes)1 and Hes-related with YRPW motif (Hey) Hey1, Hey2 and Hey-like (HeyL) expression in osteoblasts, but it is not known whether any of these target genes mediates the effect of Notch in the skeleton. We demonstrated that Notch1 activation in osteoblasts/osteocytes induces Hes1, Hey1, Hey2, and HeyL, but HeyL was induced to a greater extent than other target genes. To characterize HeyL null mice for their skeletal phenotype, microcomputed tomography (µCT) and histomorphometric analysis of HeyL null and sex-matched littermate controls was performed. µCT demonstrated modest cancellous bone osteopenia in 1 month old male mice and normal microarchitecture in 3 month old male HeyL null mice. Female HeyL null mice were not different from controls at either 1 or 3 months of age. Bone histomorphometry did not demonstrate differences between HeyL null mice of either sex and littermate controls. In conclusion, HeyL null mice do not exhibit an obvious skeletal phenotype demonstrating that HeyL is dispensable for skeletal homeostasis. J. Cell. Biochem. 118: 1819-1826, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ernesto Canalis
- Departments of Orthopaedic Surgery and Medicine, and the UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, 06030-5456
| | - Stefano Zanotti
- Departments of Orthopaedic Surgery and Medicine, and the UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, 06030-5456
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19
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McLellan MA, Rosenthal NA, Pinto AR. Cre-loxP-Mediated Recombination: General Principles and Experimental Considerations. ACTA ACUST UNITED AC 2017; 7:1-12. [DOI: 10.1002/cpmo.22] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Micheal A. McLellan
- The Jackson Laboratory; Bar Harbor Maine
- Graduate Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University; Boston Massachusetts
| | - Nadia A. Rosenthal
- The Jackson Laboratory; Bar Harbor Maine
- Australian Regenerative Medicine Institute, Monash University; Melbourne Victoria Australia
- National Heart and Lung Institute, Imperial College London; London United Kingdom
| | - Alexander R. Pinto
- The Jackson Laboratory; Bar Harbor Maine
- Australian Regenerative Medicine Institute, Monash University; Melbourne Victoria Australia
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20
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"Cre/loxP plus BAC": a strategy for direct cloning of large DNA fragment and its applications in Photorhabdus luminescens and Agrobacterium tumefaciens. Sci Rep 2016; 6:29087. [PMID: 27364376 PMCID: PMC4929569 DOI: 10.1038/srep29087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/14/2016] [Indexed: 01/23/2023] Open
Abstract
Heterologous expression has been proven to be a valid strategy for elucidating the natural products produced by gene clusters uncovered by genome sequencing projects. Efforts have been made to efficiently clone gene clusters directly from genomic DNA and several approaches have been developed. Here, we present an alternative strategy based on the site-specific recombinase system Cre/loxP for direct cloning gene clusters. A type three secretion system (T3SS) gene cluster (~32 kb) from Photorhabdus luminescens TT01 and DNA fragment (~78 kb) containing the siderophore biosynthetic gene cluster from Agrobacterium tumefaciens C58 have been successfully cloned into pBeloBAC11 with “Cre/loxP plus BAC” strategy. Based on the fact that Cre/loxP system has successfully used for genomic engineering in a wide range of organisms, we believe that this strategy could be widely used for direct cloning of large DNA fragment.
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21
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Long D, Lu W, Hao Z, Xiang Z, Zhao A. Highly efficient and inducible DNA excision in transgenic silkworms using the FLP/FRT site-specific recombination system. Transgenic Res 2016; 25:795-811. [DOI: 10.1007/s11248-016-9970-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 06/16/2016] [Indexed: 12/11/2022]
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22
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Canalis E, Schilling L, Zanotti S. Effects of Sex and Notch Signaling on the Osteocyte Cell Pool. J Cell Physiol 2016; 232:363-370. [PMID: 27192486 DOI: 10.1002/jcp.25433] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 01/23/2023]
Abstract
Osteocytes play a fundamental role in mechanotransduction and skeletal remodeling. Sex is a determinant of skeletal structure, and female C57BL/6J mice have increased osteoblast number in cancellous bone when compared to male mice. Activation of Notch in the skeleton causes profound cell-context dependent changes in skeletal physiology. To determine the impact of sex and of Notch signaling on the osteocyte cell pool, we analyzed cancellous and cortical bone of 1-6-month-old C57BL/6J or 129SvJ/C57BL/6J mice and determined the osteocyte number/area. There was an age-dependent decline in osteocyte number in cancellous bone of male but not female mice, so that 6-month-old female mice had a greater number of osteocytes than male littermates. Although differences between male and female mice were modest, female mice had ∼10-15% greater number of osteocytes/area. RNA sequence analysis of osteocyte-rich preparations did not reveal differences between sexes in the expression of genes known to influence bone homeostasis. Neither the activation of Notch1 nor the concomitant inactivation of Notch1 and Notch2 in Osterix (Sp7) or Dentin matrix protein 1 (Dmp1) expressing cells had a pronounced and consistent effect on cancellous or cortical bone osteocyte number in either sex. Moreover, inactivation of Notch1 and Notch2 in Dmp1 expressing cells did not influence the bone loss in a muscle immobilization model of skeletal unloading. In conclusion, cancellous bone osteocytes decline with age in male mice, cortical osteocytes are influenced by sex in younger mice, but osteocyte cell density is not affected substantially by Notch signaling. J. Cell. Physiol. 232: 363-370, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ernesto Canalis
- Department of Orthopaedic Surgery, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut. .,Department of Medicine, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut.
| | - Lauren Schilling
- Department of Orthopaedic Surgery, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
| | - Stefano Zanotti
- Department of Orthopaedic Surgery, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut.,Department of Medicine, UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut
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23
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Abstract
Notch 1 to 4 receptors are important determinants of cell fate and function, and Notch signaling plays an important role in skeletal development and bone remodeling. After direct interactions with ligands of the Jagged and Delta-like families, a series of cleavages release the Notch intracellular domain (NICD), which translocates to the nucleus where it induces transcription of Notch target genes. Classic gene targets of Notch are hairy and enhancer of split (Hes) and Hes-related with YRPW motif (Hey). In cells of the osteoblastic lineage, Notch activation inhibits cell differentiation and causes cancellous bone osteopenia because of impaired bone formation. In osteocytes, Notch1 has distinct effects that result in an inhibition of bone resorption secondary to an induction of osteoprotegerin and suppression of sclerostin with a consequent enhancement of Wnt signaling. Notch1 inhibits, whereas Notch2 enhances, osteoclastogenesis and bone resorption. Congenital disorders of loss- and gain-of-Notch function present with severe clinical manifestations, often affecting the skeleton. Enhanced Notch signaling is associated with osteosarcoma, and Notch can influence the invasive potential of carcinoma of the breast and prostate. Notch signaling can be controlled by the use of inhibitors of Notch activation, small peptides that interfere with the formation of a transcriptional complex, or antibodies to the extracellular domain of specific Notch receptors or to Notch ligands. In conclusion, Notch plays a critical role in skeletal development and homeostasis, and serious skeletal disorders can be attributed to alterations in Notch signaling.
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Affiliation(s)
- Stefano Zanotti
- Departments of Orthopaedic Surgery and Medicine and the UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut 06030
| | - Ernesto Canalis
- Departments of Orthopaedic Surgery and Medicine and the UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut 06030
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24
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Rocha-Martins M, Cavalheiro GR, Matos-Rodrigues GE, Martins RAP. From Gene Targeting to Genome Editing: Transgenic animals applications and beyond. AN ACAD BRAS CIENC 2016; 87:1323-48. [PMID: 26397828 DOI: 10.1590/0001-3765201520140710] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Genome modification technologies are powerful tools for molecular biology and related areas. Advances in animal transgenesis and genome editing technologies during the past three decades allowed systematic interrogation of gene function that can help model how the genome influences cellular physiology. Genetic engineering via homologous recombination (HR) has been the standard method to modify genomic sequences. Nevertheless, nuclease-guided genome editing methods that were developed recently, such as ZFN, TALEN and CRISPR/Cas, opened new perspectives for biomedical research. Here, we present a brief historical perspective of genome modification methods, focusing on transgenic mice models. Moreover, we describe how new techniques were discovered and improved, present the paradigm shifts and discuss their limitations and applications for biomedical research as well as possible future directions.
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Affiliation(s)
- Maurício Rocha-Martins
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Gabriel R Cavalheiro
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | | | - Rodrigo A P Martins
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
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25
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Meinke G, Bohm A, Hauber J, Pisabarro MT, Buchholz F. Cre Recombinase and Other Tyrosine Recombinases. Chem Rev 2016; 116:12785-12820. [PMID: 27163859 DOI: 10.1021/acs.chemrev.6b00077] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tyrosine-type site-specific recombinases (T-SSRs) have opened new avenues for the predictable modification of genomes as they enable precise genome editing in heterologous hosts. These enzymes are ubiquitous in eubacteria, prevalent in archaea and temperate phages, present in certain yeast strains, but barely found in higher eukaryotes. As tools they find increasing use for the generation and systematic modification of genomes in a plethora of organisms. If applied in host organisms, they enable precise DNA cleavage and ligation without the gain or loss of nucleotides. Criteria directing the choice of the most appropriate T-SSR system for genetic engineering include that, whenever possible, the recombinase should act independent of cofactors and that the target sequences should be long enough to be unique in a given genome. This review is focused on recent advancements in our mechanistic understanding of simple T-SSRs and their application in developmental and synthetic biology, as well as in biomedical research.
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Affiliation(s)
- Gretchen Meinke
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine , Boston, Massachusetts 02111, United States
| | - Andrew Bohm
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine , Boston, Massachusetts 02111, United States
| | - Joachim Hauber
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology , 20251 Hamburg, Germany
| | | | - Frank Buchholz
- Medical Systems Biology, UCC, Medical Faculty Carl Gustav Carus TU Dresden , 01307 Dresden, Germany
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26
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Abstract
The bacteriophage λ Red homologous recombination system has been studied over the past 50 years as a model system to define the mechanistic details of how organisms exchange DNA segments that share extended regions of homology. The λ Red system proved useful as a system to study because recombinants could be easily generated by co-infection of genetically marked phages. What emerged from these studies was the recognition that replication of phage DNA was required for substantial Red-promoted recombination in vivo, and the critical role that double-stranded DNA ends play in allowing the Red proteins access to the phage DNA chromosomes. In the past 16 years, however, the λ Red recombination system has gained a new notoriety. When expressed independently of other λ functions, the Red system is able to promote recombination of linear DNA containing limited regions of homology (∼50 bp) with the Escherichia coli chromosome, a process known as recombineering. This review explains how the Red system works during a phage infection, and how it is utilized to make chromosomal modifications of E. coli with such efficiency that it changed the nature and number of genetic manipulations possible, leading to advances in bacterial genomics, metabolic engineering, and eukaryotic genetics.
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Affiliation(s)
- Kenan C Murphy
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605
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27
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Abstract
The fields of molecular genetics, biotechnology and synthetic biology are demanding ever more sophisticated molecular tools for programmed precise modification of cell genomic DNA and other DNA sequences. This review presents the current state of knowledge and development of one important group of DNA-modifying enzymes, the site-specific recombinases (SSRs). SSRs are Nature's 'molecular machines' for cut-and-paste editing of DNA molecules by inserting, deleting or inverting precisely defined DNA segments. We survey the SSRs that have been put to use, and the types of applications for which they are suitable. We also discuss problems associated with uses of SSRs, how these problems can be minimized, and how recombinases are being re-engineered for improved performance and novel applications.
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28
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Canalis E, Bridgewater D, Schilling L, Zanotti S. Canonical Notch activation in osteocytes causes osteopetrosis. Am J Physiol Endocrinol Metab 2016; 310:E171-82. [PMID: 26578715 PMCID: PMC4719030 DOI: 10.1152/ajpendo.00395.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/12/2015] [Indexed: 01/01/2023]
Abstract
Activation of Notch1 in cells of the osteoblastic lineage inhibits osteoblast differentiation/function and causes osteopenia, whereas its activation in osteocytes causes a distinct osteopetrotic phenotype. To explore mechanisms responsible, we established the contributions of canonical Notch signaling (Rbpjκ dependent) to osteocyte function. Transgenics expressing Cre recombinase under the control of the dentin matrix protein-1 (Dmp1) promoter were crossed with Rbpjκ conditional mice to generate Dmp1-Cre(+/-);Rbpjκ(Δ/Δ) mice. These mice did not have a skeletal phenotype, indicating that Rbpjκ is dispensable for osteocyte function. To study the Rbpjκ contribution to Notch activation, Rosa(Notch) mice, where a loxP-flanked STOP cassette is placed between the Rosa26 promoter and the NICD coding sequence, were crossed with Dmp1-Cre transgenic mice and studied in the context (Dmp1-Cre(+/-);Rosa(Notch);Rbpjκ(Δ/Δ)) or not (Dmp1-Cre(+/-);Rosa(Notch)) of Rbpjκ inactivation. Dmp1-Cre(+/-);Rosa(Notch) mice exhibited increased femoral trabecular bone volume and decreased osteoclasts and bone resorption. The phenotype was reversed in the context of the Rbpjκ inactivation, demonstrating that Notch canonical signaling was accountable for the phenotype. Notch activation downregulated Sost and Dkk1 and upregulated Axin2, Tnfrsf11b, and Tnfsf11 mRNA expression, and these effects were not observed in the context of the Rbpjκ inactivation. In conclusion, Notch activation in osteocytes suppresses bone resorption and increases bone volume by utilization of canonical signals that also result in the inhibition of Sost and Dkk1 and upregulation of Wnt signaling.
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Affiliation(s)
- Ernesto Canalis
- Department of Orthopedic Surgery and the University of Connecticut Musculoskeletal Institute, Farmington, Connecticut; and Department of Medicine, University of Connecticut Health, Farmington, Connecticut
| | - David Bridgewater
- Department of Orthopedic Surgery and the University of Connecticut Musculoskeletal Institute, Farmington, Connecticut; and
| | - Lauren Schilling
- Department of Orthopedic Surgery and the University of Connecticut Musculoskeletal Institute, Farmington, Connecticut; and
| | - Stefano Zanotti
- Department of Orthopedic Surgery and the University of Connecticut Musculoskeletal Institute, Farmington, Connecticut; and Department of Medicine, University of Connecticut Health, Farmington, Connecticut
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Zanotti S, Canalis E. The Dmp1-SOST Transgene Interacts With and Downregulates the Dmp1-Cre Transgene and the Rosa(Notch) Allele. J Cell Biochem 2015; 117:1222-32. [PMID: 26456319 DOI: 10.1002/jcb.25405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 10/08/2015] [Indexed: 11/10/2022]
Abstract
Activation of Notch1 in osteocytes of Rosa(Notch) mice, where a loxP-flanked STOP cassette and the Nicd coding sequence were targeted to the reverse orientation splice acceptor (Rosa)26 locus, causes osteopetrosis associated with suppressed Sost expression and enhanced Wnt signaling. To determine whether Sost downregulation mediates the effects of Notch activation in osteocytes, Rosa(Notch) mice were crossed with transgenics expressing Cre recombinase or SOST under the control of the dentin matrix protein (Dmp)1 promoter. Dmp1-SOST transgenics displayed vertebral osteopenia and a modest femoral cancellous and cortical bone phenotype, whereas hemizygous Dmp1-Cre transgenics heterozygous for the Rosa(Notch) allele (Dmp1-Cre;Rosa(Notch)) exhibited osteopetrosis. The phenotype of Notch activation in osteocytes was prevented in Dmp1-Cre;Rosa(Notch) mice hemizygous for the Dmp1-SOST transgene. The effect was associated with downregulated Notch signaling and suppressed Dmp1 and Rosa26 expression. To test whether SOST regulates Notch expression in osteocytes, cortical bone cultures from Dmp1-Cre;Rosa(Notch) mice or from Rosa(Notch) control littermates were exposed to recombinant human SOST. The addition of SOST had only modest effects on Notch target gene mRNA levels and suppressed Dmp1, but not Cre or Rosa26, expression. These findings suggest that prevention of the Dmp1-Cre;Rosa(Notch) skeletal phenotype by Dmp1-SOST is not secondary to SOST expression but to interactions among the Dmp1-SOST and Dmp1-Cre transgenes and the Rosa26 locus. In conclusion, the Dmp1-SOST transgene suppresses the expression of the Dmp1-Cre transgene and of Rosa26.
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Affiliation(s)
- Stefano Zanotti
- Departments of Orthopaedic Surgery and Medicine, and The UConn Musculoskeletal Institute, UConn Health, Farmington, 06030, Connecticut
| | - Ernesto Canalis
- Departments of Orthopaedic Surgery and Medicine, and The UConn Musculoskeletal Institute, UConn Health, Farmington, 06030, Connecticut
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Kage-Nakadai E, Imae R, Suehiro Y, Yoshina S, Hori S, Mitani S. A conditional knockout toolkit for Caenorhabditis elegans based on the Cre/loxP recombination. PLoS One 2014; 9:e114680. [PMID: 25474529 PMCID: PMC4256423 DOI: 10.1371/journal.pone.0114680] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 11/12/2014] [Indexed: 11/19/2022] Open
Abstract
Conditional knockout (cKO) based on site-specific recombination (SSR) technology is a powerful approach for estimating gene functions in a spatially and temporally specific manner in many model animals. In Caenorhabditis elegans (C. elegans), spatial- and temporal-specific gene functions have been largely determined by mosaic analyses, rescue experiments and feeding RNAi methods. To develop a systematic and stable cKO system in C. elegans, we generated Cre recombinase expression vectors that are driven by various tissue-specific or heat-shock promoters. Validation using Cre-mediated fluorescence protein inactivation or activation systems demonstrated successful Cre-dependent loxP excision. We established a collection of multi-copy Cre transgenic strains for each evaluated vector. To evaluate our Cre/loxP-based cKO system, we generated sid-1 deletion mutants harboring floxed sid-1 single-copy integration (SCI) using ultraviolet trimethylpsoralen (UV/TMP) methods. sid-1 mutants that were rescued by the floxed sid-1 SCI were then crossed with the Pdpy-7::Cre strain for cKO in the hypodermis. The sid-1 cKO animals were resistant to bli-3 RNAi, which causes the Bli-phenotyple in the hypodermis, but they were sensitive to unc-22 RNAi, which leads to twitching of the body wall muscle. Our system, which is based on the combination of a transgenic Cre collection, pre-existing deletion mutants, and UV/TMP SCI methods, provided a systematic approach for cKO in C. elegans.
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Affiliation(s)
- Eriko Kage-Nakadai
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
- The OCU Advanced Research Institute for Natural Science and Technology, Osaka City University, Osaka, Japan
| | - Rieko Imae
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
| | - Yuji Suehiro
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
| | - Sawako Yoshina
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
| | - Sayaka Hori
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
| | - Shohei Mitani
- Department of Physiology, Tokyo Women’s Medical University School of Medicine, Tokyo, Japan
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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Canalis E, Kranz L, Zanotti S. Nemo-like kinase regulates postnatal skeletal homeostasis. J Cell Physiol 2014; 229:1736-43. [PMID: 24664870 DOI: 10.1002/jcp.24625] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 03/20/2014] [Indexed: 01/04/2023]
Abstract
Nemo-like kinase (Nlk) is related to the mitogen-activated protein (MAP) kinases and known to regulate signaling pathways involved in osteoblastogenesis. In vitro Nlk suppresses osteoblastogenesis, but the consequences of the Nlk inactivation in the skeleton in vivo are unknown. To study the function of Nlk, Nlk(loxP/loxP) mice, where the Nlk exon2 is flanked by lox(P) sequences, were mated with mice expressing the Cre recombinase under the control of the paired-related homeobox gene 1 (Prx1) enhancer (Prx1-Cre), the Osterix (Osx-Cre) or the osteocalcin/bone gamma carboxyglutamate protein (Bglap-Cre) promoter. Prx1-Cre;Nlk(Δ/Δ) mice did not exhibit a skeletal phenotype except for a modest increase in trabecular number and connectivity observed only in 3-month-old male mice. Osx-Cre;Nlk(Δ/Δ) male and female mice exhibited an increase in trabecular bone volume secondary to an increased trabecular number at 3 months of age. Bone histomorphometry revealed a decrease in osteoclast number and eroded surface in male mice, and decreased osteoblast number and function in female mice. Expression of osteoprotegerin mRNA was increased in calvarial extracts, explaining the decreased osteoclast and osteoblast number. The conditional deletion of Nlk in mature osteoblasts (Bglap-Cre;Nlk(Δ/Δ) ) resulted in no skeletal phenotype in 1- to 6-month-old male or female mice. In conclusion, when expressed in undifferentiated osteoblasts, Nlk is a negative regulator of skeletal homeostasis possibly by targeting signals that regulate osteoclastogenesis and bone resorption.
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Affiliation(s)
- Ernesto Canalis
- Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut; The University of Connecticut School of Medicine, Farmington, Connecticut
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Canalis E, Zanotti S, Smerdel-Ramoya A. Connective tissue growth factor is a target of notch signaling in cells of the osteoblastic lineage. Bone 2014; 64:273-80. [PMID: 24792956 PMCID: PMC4069863 DOI: 10.1016/j.bone.2014.04.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 04/03/2014] [Accepted: 04/23/2014] [Indexed: 12/15/2022]
Abstract
Connective tissue growth factor (Ctgf) or CCN2 is a protein synthesized by osteoblasts necessary for skeletal homeostasis, although its overexpression inhibits osteogenic signals and bone formation. Ctgf is induced by bone morphogenetic proteins, transforming growth factor β and Wnt; and in the present studies, we explored whether Notch regulated Ctgf expression in osteoblasts. We employed Rosa(Notch) mice, where the Notch intracellular domain (NICD) is expressed following the excision of a STOP cassette, placed between the Rosa26 promoter and NICD. Notch was activated by transduction of adenoviral vectors expressing Cre recombinase (Ad-CMV-Cre). Notch induced Ctgf mRNA levels in a time dependent manner and increased Ctgf heterogeneous nuclear RNA. Notch also destabilized Ctgf mRNA shortening its half-life from 13h to 3h. The effect of Notch on Ctgf expression was lost following Rbpjκ downregulation, demonstrating that it was mediated by Notch canonical signaling. However, downregulation of the classic Notch target genes Hes1, Hey1 and Hey2 did not modify the effect of Notch on Ctgf expression. Wild type osteoblasts exposed to immobilized Delta-like 1 displayed enhanced Notch signaling and increased Ctgf expression. In addition to the effects of Notch in vitro, Notch induced Ctgf in vivo, and calvariae and femurs from Rosa(Notch) mice mated with transgenics expressing the Cre recombinase in cells of the osteoblastic lineage exhibited increased expression of Ctgf. In conclusion, Ctgf is a target of Notch canonical signaling in osteoblasts, and may act in concert with Notch to regulate skeletal homeostasis.
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Affiliation(s)
- Ernesto Canalis
- Department of Research, Saint Francis Hospital and Medical Center, Hartford, CT, 06105; The University of Connecticut School of Medicine, Farmington, CT, 06030.
| | - Stefano Zanotti
- Department of Research, Saint Francis Hospital and Medical Center, Hartford, CT, 06105; The University of Connecticut School of Medicine, Farmington, CT, 06030.
| | - Anna Smerdel-Ramoya
- Department of Research, Saint Francis Hospital and Medical Center, Hartford, CT, 06105.
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All-in-One inducible lentiviral vector systems based on drug controlled FLP recombinase. Biomaterials 2014; 35:4345-56. [DOI: 10.1016/j.biomaterials.2014.01.057] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/23/2014] [Indexed: 01/11/2023]
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Gierut JJ, Jacks TE, Haigis KM. Strategies to achieve conditional gene mutation in mice. Cold Spring Harb Protoc 2014; 2014:339-49. [PMID: 24692485 DOI: 10.1101/pdb.top069807] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The laboratory mouse is an ideal model organism for studying disease because it is physiologically similar to human and also because its genome is readily manipulated. Genetic engineering allows researchers to introduce specific loss-of-function or gain-of-function mutations into genes and then to study the resulting phenotypes in an in vivo context. One drawback of using traditional transgenic and knockout mice to study human diseases is that many mutations passed through the germline can profoundly affect development, thus impeding the study of disease phenotypes in adults. New technology has made it possible to generate conditional mutations that can be introduced in a spatially and/or temporally restricted manner. Mouse strains carrying conditional mutations represent valuable experimental models for the study of human diseases and they can be used to develop strategies for prevention and treatment of these diseases. In this article, we will describe the most widely used DNA recombinase systems used to achieve conditional gene mutation in mouse models and discuss how these systems can be employed in vivo.
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Affiliation(s)
- Jessica J Gierut
- Molecular Pathology Unit and Center for Cancer Research, Massachusetts General Hospital, Department of Pathology, Harvard Medical School, Charlestown, Massachusetts 02129
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Sajgo S, Ghinia MG, Shi M, Liu P, Dong L, Parmhans N, Popescu O, Badea TC. Dre - Cre sequential recombination provides new tools for retinal ganglion cell labeling and manipulation in mice. PLoS One 2014; 9:e91435. [PMID: 24608965 PMCID: PMC3946778 DOI: 10.1371/journal.pone.0091435] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 02/11/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Genetic targeting methods have greatly advanced our understanding of many of the 20 Retinal Ganglion Cell (RGC) types conveying visual information from the eyes to the brain. However, the complexity and partial overlap of gene expression patterns in RGCs call for genetic intersectional or sparse labeling strategies. Loci carrying the Cre recombinase in conjunction with conditional knock-out, reporter or other genetic tools can be used for targeted cell type ablation and functional manipulation of specific cell populations. The three members of the Pou4f family of transcription factors, Brn3a, Brn3b and Brn3c, expressed early during RGC development and in combinatorial pattern amongst RGC types are excellent candidates for such gene manipulations. METHODS AND FINDINGS We generated conditional Cre knock-in alleles at the Brn3a and Brn3b loci, Brn3a(CKOCre) and Brn3b(CKOCre). When crossed to mice expressing the Dre recombinase, the endogenous Brn3 gene expressed by Brn3a(CKOCre) or Brn3b(CKOCre) is removed and replaced with a Cre recombinase, generating Brn3a(Cre) and Brn3b(Cre) knock-in alleles. Surprisingly both Brn3a(Cre) and Brn3b(Cre) knock-in alleles induce early ubiquitous recombination, consistent with germline expression. However in later stages of development, their expression is limited to the expected endogenous pattern of the Brn3a and Brn3b genes. We use the Brn3a(Cre) and Brn3b(Cre) alleles to target a Cre dependent Adeno Associated Virus (AAV) reporter to RGCs and demonstrate its use in morphological characterization, early postnatal gene delivery and tracing the expression of Brn3 genes in RGCs. CONCLUSIONS Dre recombinase effectively recombines the Brn3a(CKOCre) and Brn3b(CKOCre) alleles containing its roxP target sites. Sequential Dre to Cre recombination reveals Brn3a and Brn3b expression in early mouse development. The generated Brn3a(Cre) and Brn3b(Cre) alleles are useful tools that can target exogenously delivered Cre dependent reagents to RGCs in early postnatal development, opening up a large range of potential applications.
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Affiliation(s)
- Szilard Sajgo
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
- Biology Department, Babes-Bolyai University, Cluj-Napoca, Cluj, Romania
| | - Miruna Georgiana Ghinia
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
- Biology Department, Babes-Bolyai University, Cluj-Napoca, Cluj, Romania
| | - Melody Shi
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Pinghu Liu
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Lijin Dong
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Nadia Parmhans
- National Eye Institute, NIH, Bethesda, Maryland, United States of America
| | - Octavian Popescu
- Biology Department, Babes-Bolyai University, Cluj-Napoca, Cluj, Romania
- Institute of Biology, Romanian Academy, Bucharest, Romania
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Ishikawa T, Wakabayashi-Nakao K, Nakagawa H. Methods to examine the impact of nonsynonymous SNPs on protein degradation and function of human ABC transporter. Methods Mol Biol 2014; 1015:225-50. [PMID: 23824860 DOI: 10.1007/978-1-62703-435-7_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Clinical studies have strongly suggested that genetic polymorphisms and/or mutations of certain ATP-binding cassette (ABC) transporter genes might be regarded as significant factors affecting patients' responses to medication and/or the risk of diseases. In the case of ABCG2, certain single nucleotide polymorphisms (SNPs) in the encoding gene alter the substrate specificity and/or enhance endoplasmic reticulum-associated degradation (ERAD) of the de novo synthesized ABCG2 protein via the ubiquitin-mediated proteasomal proteolysis pathway. Hitherto accumulated clinical data imply that several nonsynonymous SNPs affect the ABCG2-mediated clearance of drugs or cellular metabolites, although some controversies still exist. Therefore, we recently developed high-speed functional screening and ERAD of ABC transporters so as to evaluate the effect of genetic polymorphisms on their function and protein expression levels in vitro. In this chapter we present in vitro experimental methods to elucidate the impact of nonsynonymous SNPs on protein degradation of ABCG2 as well as on its transport function.
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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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Long D, Zhao A, Xu L, Lu W, Guo Q, Zhang Y, Xiang Z. In vivo site-specific integration of transgene in silkworm via PhiC31 integrase-mediated cassette exchange. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:997-1008. [PMID: 23974010 DOI: 10.1016/j.ibmb.2013.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 07/24/2013] [Accepted: 08/07/2013] [Indexed: 06/02/2023]
Abstract
Current techniques for genetic engineering of the silkworm Bombyx mori genome utilize transposable elements, which result in positional effects and insertional mutagenesis through random insertion of exogenous DNA. New methods for introducing transgenes at specific positions are therefore needed to overcome the limitations of transposon-based strategies. Although site-specific recombination systems have proven powerful tools for genome manipulation in many organisms, their use has not yet been well established for the integration of transgenes in the silkworm. We describe a method for integrating target genes at pre-defined chromosomal sites in the silkworm via phiC31/att site-specific recombination system-mediated cassette exchange. Successful recombinase-mediated cassette exchange (RMCE) was observed in the two transgenic target strains with an estimated transformation efficiency of 3.84-7.01%. Our results suggest that RMCE events between chromosomal attP/attP target sites and incoming attB/attB sites were more frequent than those in the reciprocal direction. This is the first report of in vivo RMCE via phiC31 integrase in the silkworm, and thus represents a key step toward establishing genome manipulation technologies in silkworms and other lepidopteran species.
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Affiliation(s)
- Dingpei Long
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, BeiBei, Chongqing 400716, China
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Gaj T, Sirk SJ, Barbas CF. Expanding the scope of site-specific recombinases for genetic and metabolic engineering. Biotechnol Bioeng 2013; 111:1-15. [PMID: 23982993 DOI: 10.1002/bit.25096] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/12/2013] [Accepted: 08/13/2013] [Indexed: 12/20/2022]
Abstract
Site-specific recombinases are tremendously valuable tools for basic research and genetic engineering. By promoting high-fidelity DNA modifications, site-specific recombination systems have empowered researchers with unprecedented control over diverse biological functions, enabling countless insights into cellular structure and function. The rigid target specificities of many sites-specific recombinases, however, have limited their adoption in fields that require highly flexible recognition abilities. As a result, intense effort has been directed toward altering the properties of site-specific recombination systems by protein engineering. Here, we review key developments in the rational design and directed molecular evolution of site-specific recombinases, highlighting the numerous applications of these enzymes across diverse fields of study.
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Affiliation(s)
- Thomas Gaj
- The Skaggs Institute for Chemical Biology and the Departments of Chemistry and Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, 92037
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Deussing JM. Targeted mutagenesis tools for modelling psychiatric disorders. Cell Tissue Res 2013; 354:9-25. [PMID: 24078022 DOI: 10.1007/s00441-013-1708-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 07/16/2013] [Indexed: 12/15/2022]
Abstract
In the 1980s, the basic principles of gene targeting were discovered and forged into sharp tools for efficient and precise engineering of the mouse genome. Since then, genetic mouse models have substantially contributed to our understanding of major neurobiological concepts and are of utmost importance for our comprehension of neuropsychiatric disorders. The "domestication" of site-specific recombinases and the continuous creative technological developments involving the implementation of previously identified biological principles such as transcriptional and posttranslational control now enable conditional mutagenesis with high spatial and temporal resolution. The initiation and successful accomplishment of large-scale efforts to annotate functionally the entire mouse genome and to build strategic resources for the research community have significantly accelerated the rapid proliferation and broad propagation of mouse genetic tools. Addressing neurobiological processes with the assistance of genetic mouse models is a routine procedure in psychiatric research and will be further extended in order to improve our understanding of disease mechanisms. In light of the highly complex nature of psychiatric disorders and the current lack of strong causal genetic variants, a major future challenge is to model of psychiatric disorders more appropriately. Humanized mice, and the recently developed toolbox of site-specific nucleases for more efficient and simplified tailoring of the genome, offer the perspective of significantly improved models. Ultimately, these tools will push the limits of gene targeting beyond the mouse to allow genome engineering in any model organism of interest.
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Affiliation(s)
- Jan M Deussing
- Max Planck Institute of Psychiatry, Molecular Neurogenetics, Kraepelinstrasse 2-10, 80804, Munich, Germany,
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Weber T, Köster R. Genetic tools for multicolor imaging in zebrafish larvae. Methods 2013; 62:279-91. [DOI: 10.1016/j.ymeth.2013.07.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 07/08/2013] [Accepted: 07/16/2013] [Indexed: 02/06/2023] Open
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Pande K, Chen C, Noble SM. Passage through the mammalian gut triggers a phenotypic switch that promotes Candida albicans commensalism. Nat Genet 2013; 45:1088-91. [PMID: 23892606 PMCID: PMC3758371 DOI: 10.1038/ng.2710] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 06/28/2013] [Indexed: 12/21/2022]
Abstract
Among ~5,000,000 fungal species,1Candida albicans is exceptional in its lifelong association with humans, either within the gastrointestinal microbiome or as an invasive pathogen.2 Opportunistic infections are generally ascribed to defective host immunity 3 but may require specific microbial programs. Here, we report that exposure of C. albicans to the mammalian gut triggers a developmental switch, driven by the Wor1 transcription factor, to a commensal cell type. Wor1 expression was previously observed only in rare genetic backgrounds,4–6 where it controls a white-opaque switch for mating.4–7 We show that passage of wild-type cells through the murine gastrointestinal tract triggers WOR1 expression and a novel phenotypic switch. The resulting GUT (Gastrointestinally-IndUced Transition) cells differ morphologically and functionally from previously defined cell types, including opaque, and express a transcriptome that is optimized for the digestive tract. The white-GUT switch illuminates how a microorganism utilizes distinct genetic programs to transition between commensalism and invasive pathogenesis.
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Affiliation(s)
- Kalyan Pande
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, California, USA
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Canalis E, Adams DJ, Boskey A, Parker K, Kranz L, Zanotti S. Notch signaling in osteocytes differentially regulates cancellous and cortical bone remodeling. J Biol Chem 2013; 288:25614-25625. [PMID: 23884415 DOI: 10.1074/jbc.m113.470492] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Notch receptors play a role in skeletal development and homeostasis, and Notch activation in undifferentiated and mature osteoblasts causes osteopenia. In contrast, Notch activation in osteocytes increases bone mass, but the mechanisms involved and exact functions of Notch are not known. In this study, Notch1 and -2 were inactivated preferentially in osteocytes by mating Notch1/2 conditional mice, where Notch alleles are flanked by loxP sequences, with transgenics expressing Cre directed by the Dmp1 (dentin matrix protein 1) promoter. Notch1/2 conditional null male and female mice exhibited an increase in trabecular bone volume due to an increase in osteoblasts and decrease in osteoclasts. In male null mice, this was followed by an increase in osteoclast number and normalization of bone volume. To activate Notch preferentially in osteocytes, Dmp1-Cre transgenics were crossed with Rosa(Notch) mice, where a loxP-flanked STOP cassette is placed between the Rosa26 promoter and Notch1 intracellular domain sequences. Dmp1-Cre(+/-);Rosa(Notch) mice exhibited an increase in trabecular bone volume due to decreased bone resorption and an increase in cortical bone due to increased bone formation. Biomechanical and chemical properties were not affected. Osteoprotegerin mRNA was increased, sclerostin and dickkopf1 mRNA were decreased, and Wnt signaling was enhanced in Dmp1-Cre(+/-);Rosa(Notch) femurs. Botulinum toxin A-induced muscle paralysis caused pronounced osteopenia in control mice, but bone mass was preserved in mice harboring the Notch activation in osteocytes. In conclusion, Notch plays a unique role in osteocytes, up-regulates osteoprotegerin and Wnt signaling, and differentially regulates trabecular and cortical bone homeostasis.
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Affiliation(s)
- Ernesto Canalis
- From the Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105,; the University of Connecticut School of Medicine, Farmington, Connecticut 06030,.
| | - Douglas J Adams
- the Department of Orthopedic Surgery, University of Connecticut Health Center, Farmington, Connecticut 06030, and
| | - Adele Boskey
- the Hospital for Special Surgery, New York, New York 10021
| | - Kristen Parker
- From the Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105
| | - Lauren Kranz
- From the Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105
| | - Stefano Zanotti
- From the Department of Research, Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105,; the University of Connecticut School of Medicine, Farmington, Connecticut 06030
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Fan HF, Ma CH, Jayaram M. Real-time single-molecule tethered particle motion analysis reveals mechanistic similarities and contrasts of Flp site-specific recombinase with Cre and λ Int. Nucleic Acids Res 2013; 41:7031-47. [PMID: 23737451 PMCID: PMC3737535 DOI: 10.1093/nar/gkt424] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Flp, a tyrosine site-specific recombinase coded for by the selfish two micron plasmid of Saccharomyces cerevisiae, plays a central role in the maintenance of plasmid copy number. The Flp recombination system can be manipulated to bring about a variety of targeted DNA rearrangements in its native host and under non-native biological contexts. We have performed an exhaustive analysis of the Flp recombination pathway from start to finish by using single-molecule tethered particle motion (TPM). The recombination reaction is characterized by its early commitment and high efficiency, with only minor detraction from ‘non-productive’ and ‘wayward’ complexes. The recombination synapse is stabilized by strand cleavage, presumably by promoting the establishment of functional interfaces between adjacent Flp monomers. Formation of the Holliday junction intermediate poses a rate-limiting barrier to the overall reaction. Isomerization of the junction to the conformation favoring its resolution in the recombinant mode is not a slow step. Consistent with the completion of nearly every initiated reaction, the chemical steps of strand cleavage and exchange are not reversible during a recombination event. Our findings demonstrate similarities and differences between Flp and the mechanistically related recombinases λ Int and Cre. The commitment and directionality of Flp recombination revealed by TPM is consistent with the physiological role of Flp in amplifying plasmid DNA.
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Affiliation(s)
- Hsiu-Fang Fan
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan.
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46
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Recombinase-mediated cassette exchange (RMCE) — A rapidly-expanding toolbox for targeted genomic modifications. Gene 2013. [DOI: 10.1016/j.gene.2012.11.016] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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47
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Canalis E, Parker K, Feng JQ, Zanotti S. Osteoblast lineage-specific effects of notch activation in the skeleton. Endocrinology 2013; 154:623-34. [PMID: 23275471 PMCID: PMC3548181 DOI: 10.1210/en.2012-1732] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Transgenic overexpression of the Notch1 intracellular domain inhibits osteoblast differentiation and causes osteopenia, and inactivation of Notch1 and Notch2 increases bone volume transiently and induces osteoblastic differentiation. However, the biology of Notch is cell-context-dependent, and consequences of Notch activation in cells of the osteoblastic lineage at various stages of differentiation and in osteocytes have not been defined. For this purpose, Rosa(Notch) mice, where a loxP-flanked STOP cassette placed between the Rosa26 promoter and the NICD coding sequence, were crossed with transgenics expressing the Cre recombinase under the control of the Osterix (Osx), Osteocalcin (Oc), Collagen 1a1 (Col2.3), or Dentin matrix protein1 (Dmp1) promoters. At 1 month, Osx-Cre;Rosa(Notch) and Oc-Cre;Rosa(Notch) mice exhibited osteopenia due to impaired bone formation. In contrast, Col2.3-Cre;Rosa(Notch) and Dmp1-Cre;Rosa(Notch) exhibited increased femoral trabecular bone volume due to a decrease in osteoclast number and eroded surface. In the four lines studied, cortical bone was either not present, was porous, or had the appearance of trabecular bone. Oc-Cre;Rosa(Notch) and Col2.3-Cre;Rosa(Notch) mice exhibited early lethality so that their adult phenotype was not established. At 3 months, Osx-Cre;Rosa(Notch) and Dmp1-Cre;Rosa(Notch) mice displayed increased bone volume, and increased osteoblasts although calcein-demeclocycline labels were diffuse and fragmented, indicating abnormal bone formation. In conclusion, Notch effects in the skeleton are cell-context-dependent. When expressed in immature osteoblasts, Notch arrests their differentiation, causing osteopenia, and when expressed in osteocytes, it causes an initial suppression of bone resorption and increased bone volume, a phenotype that evolves as the mice mature.
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Affiliation(s)
- Ernesto Canalis
- Department of Research, Saint Francis Hospital and Medical Center, 114 Woodland Street, Hartford, CT 06105-1299, USA.
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Abstract
The ability to introduce DNA sequences (e.g., genes) of interest into the germline genome has rendered the mouse a powerful and indispensable experimental model in fundamental and medical research. The DNA sequences can be integrated into the genome randomly or into a specific locus by homologous recombination, in order to: (1) delete or insert mutations into genes of interest to determine their function, (2) introduce human genes into the genome of mice to generate animal models enabling study of human-specific genes and diseases, e.g., mice susceptible to infections by human-specific pathogens of interest, (3) introduce individual genes or genomes of pathogens (such as viruses) in order to examine the contributions of such genes to the pathogenesis of the parent pathogens, (4) and last but not least introduce reporter genes that allow monitoring in vivo or ex vivo the expression of genes of interest. Furthermore, the use of recombination systems, such as Cre/loxP or FRT/FLP, enables conditional induction or suppression of gene expression of interest in a restricted period of mouse's lifetime, in a particular cell type, or in a specific tissue. In this review, we will give an updated summary of the gene targeting technology and discuss some important considerations in the design of gene-targeted mice.
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Affiliation(s)
- Hicham Bouabe
- Laboratory of Lymphocyte Signalling and Development, Babraham Institute, Cambridge, UK
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Cre-mediated targeted gene activation in the middle silk glands of transgenic silkworms (Bombyx mori). Transgenic Res 2012; 22:607-19. [DOI: 10.1007/s11248-012-9677-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 11/14/2012] [Indexed: 10/27/2022]
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Karimova M, Abi-Ghanem J, Berger N, Surendranath V, Pisabarro MT, Buchholz F. Vika/vox, a novel efficient and specific Cre/loxP-like site-specific recombination system. Nucleic Acids Res 2012; 41:e37. [PMID: 23143104 PMCID: PMC3553980 DOI: 10.1093/nar/gks1037] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Targeted genome engineering has become an important research area for diverse disciplines, with site-specific recombinases (SSRs) being among the most popular genome engineering tools. Their ability to trigger excision, integration, inversion and translocation has made SSRs an invaluable tool to manipulate DNA in vitro and in vivo. However, sophisticated strategies that combine different SSR systems are ever increasing. Hence, the demand for additional precise and efficient recombinases is dictated by the increasing complexity of the genetic studies. Here, we describe a novel site-specific recombination system designated Vika/vox. Vika originates from a degenerate bacteriophage of Vibrio coralliilyticus and shares low sequence similarity to other tyrosine recombinases, but functionally carries out a similar type of reaction. We demonstrate that Vika is highly specific in catalyzing vox recombination without recombining target sites from other SSR systems. We also compare the recombination activity of Vika/vox with other SSR systems, providing a guideline for deciding on the most suitable enzyme for a particular application and demonstrate that Vika expression does not cause cytotoxicity in mammalian cells. Our results show that Vika/vox is a novel powerful and safe instrument in the 'genetic toolbox' that can be used alone or in combination with other SSRs in heterologous hosts.
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Affiliation(s)
- Madina Karimova
- Medical Systems Biology, Medical Faculty and University Hospital Carl Gustav Carus, University of Technology, Fetscherstrasse 74, 01307 Dresden, Germany
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