1
|
Bertozzi TM, Ferguson-Smith AC. Metastable epialleles and their contribution to epigenetic inheritance in mammals. Semin Cell Dev Biol 2020; 97:93-105. [PMID: 31551132 DOI: 10.1016/j.semcdb.2019.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 08/15/2019] [Accepted: 08/20/2019] [Indexed: 02/02/2023]
Abstract
Many epigenetic differences between individuals are driven by genetic variation. Mammalian metastable epialleles are unusual in that they show variable DNA methylation states between genetically identical individuals. The occurrence of such states across generations has resulted in their consideration by many as strong evidence for epigenetic inheritance in mammals, with the classic Avy and AxinFu mouse models - each products of repeat element insertions - being the most widely accepted examples. Equally, there has been interest in exploring their use as epigenetic biosensors given their susceptibility to environmental compromise. Here we review the classic murine metastable epialleles as well as more recently identified candidates, with the aim of providing a more holistic understanding of their biology. We consider the extent to which epigenetic inheritance occurs at metastable epialleles and explore the limited mechanistic insights into the establishment of their variable epigenetic states. We discuss their environmental modulation and their potential relevance in genome regulation. In light of recent whole-genome screens for novel metastable epialleles, we point out the need to reassess their biological relevance in multi-generational studies and we highlight their value as a model to study repeat element silencing as well as the mechanisms and consequences of mammalian epigenetic stochasticity.
Collapse
Affiliation(s)
- Tessa M Bertozzi
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | | |
Collapse
|
2
|
Michael HT, Graff-Cherry C, Chin S, Rauck C, Habtemichael AD, Bunda P, Smith T, Campos MM, Bharti K, Arnheiter H, Merlino G, Day CP. Partial Rescue of Ocular Pigment Cells and Structure by Inducible Ectopic Expression of Mitf-M in MITF-Deficient Mice. Invest Ophthalmol Vis Sci 2019; 59:6067-6073. [PMID: 30590377 PMCID: PMC6314104 DOI: 10.1167/iovs.18-25186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose Complete deficiency of microphthalmia transcription factor (MITF) in Mitfmi-vga9/mi-vga9 mice is associated with microphthalmia, retinal dysplasia, and albinism. We investigated the ability of dopachrome tautomerase (DCT) promoter-mediated inducible ectopic expression of Mitf-M to rescue these phenotypic abnormalities. Methods A new mouse line was created with doxycycline-inducible ectopic Mitf-M expression on an Mitf-deficient Mitfmi-vga9 background (DMV mouse). Adult DMV mice were phenotypically characterized and tissues were collected for histology, immunohistochemistry, and evaluation of Mitf, pigmentary genes, and retinal pigment epithelium (RPE) gene expression. Results Ectopic Mitf-M expression was specifically induced in the eyes, but was not detected in the skin of DMV mice. Inducible expression of Mitf-M partially rescued the microphthalmia, RPE structure, and pigmentation as well as a subset of the choroidal and iris melanocytes but not cutaneous melanocytes. RPE function and vision were not restored in the DMV mice. Conclusions Ectopic expression of Mitf-M during development of Mitf-deficient mice is capable of partially rescuing ocular and retinal structures and uveal melanocytes. These findings provide novel information about the roles of Mitf isoforms in the development of mouse eyes.
Collapse
Affiliation(s)
- Helen T Michael
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Cari Graff-Cherry
- Laboratory Animal Science Program, National Frederick Laboratory for Cancer Research, National Insitutes of Health, Frederick, Maryland, United States
| | - Sung Chin
- Laboratory Animal Science Program, National Frederick Laboratory for Cancer Research, National Insitutes of Health, Frederick, Maryland, United States
| | - Corinne Rauck
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Amelework D Habtemichael
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Patricia Bunda
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Tunde Smith
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Maria M Campos
- Histopathology Core Facility, National Eye Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Kapil Bharti
- Unit on Ocular and Stem Cell Translational Research, National Eye Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Heinz Arnheiter
- Scientist Emeritus, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States
| | - Glenn Merlino
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Insitutes of Health, Bethesda, Maryland, United States
| | - Chi-Ping Day
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Insitutes of Health, Bethesda, Maryland, United States
| |
Collapse
|
3
|
Hoffman GE, Schrode N, Flaherty E, Brennand KJ. New considerations for hiPSC-based models of neuropsychiatric disorders. Mol Psychiatry 2019; 24:49-66. [PMID: 29483625 PMCID: PMC6109625 DOI: 10.1038/s41380-018-0029-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 02/06/2023]
Abstract
The development of human-induced pluripotent stem cells (hiPSCs) has made possible patient-specific modeling across the spectrum of human disease. Here, we discuss recent advances in psychiatric genomics and post-mortem studies that provide critical insights concerning cell-type composition and sample size that should be considered when designing hiPSC-based studies of complex genetic disease. We review recent hiPSC-based models of SZ, in light of our new understanding of critical power limitations in the design of hiPSC-based studies of complex genetic disorders. Three possible solutions are a movement towards genetically stratified cohorts of rare variant patients, application of CRISPR technologies to engineer isogenic neural cells to study the impact of common variants, and integration of advanced genetics and hiPSC-based datasets in future studies. Overall, we emphasize that to advance the reproducibility and relevance of hiPSC-based studies, stem cell biologists must contemplate statistical and biological considerations that are already well accepted in the field of genetics. We conclude with a discussion of the hypothesis of biological convergence of disease-through molecular, cellular, circuit, and patient level phenotypes-and how this might emerge through hiPSC-based studies.
Collapse
Affiliation(s)
- Gabriel E Hoffman
- Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Genetics and Genomics, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Nadine Schrode
- Department of Genetics and Genomics, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Erin Flaherty
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Kristen J Brennand
- Department of Genetics and Genomics, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
| |
Collapse
|
4
|
Comparative study of the immunological characteristics of three different C57BL/6N mouse substrains. Lab Anim Res 2017; 33:124-131. [PMID: 28747978 PMCID: PMC5527138 DOI: 10.5625/lar.2017.33.2.124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/09/2017] [Accepted: 06/09/2017] [Indexed: 11/21/2022] Open
Abstract
Inbred mice, a systematically developed homogeneous animal, have been developed to maintain experimental reproducibility and to minimize experimental variables in animal-based studies. In particular, C57BL/6 mice are frequently used in experiments into immunology and antitumor activity experiments. This study was compared the immunological characteristics of C57BL/6NKorl, a Korean developed experimental animal resource, with those of two other C57BL/6N substrains. Mouse body, thymus, and spleen weights in C57BL/6NKorl were not significantly different from those of the other two C57BL/6N substrains. Among the three substrains, there was no difference in the distribution of T and B cells, which are lymphocytes involved in adaptive immunity, and no difference in NK cells related to innate immunity. Results for macrophages and granulocytes, which have roles in innate immunity, were similar in all three substrains. In order to investigate the expressions of major histocompatibility complex (MHC) molecules and allogenic antigens, splenocytes were separated from obtained spleen and analyzed by using flow cytometry. MHC class I and II molecules, which are important during self/non-self-discrimination, were similar in the three substrains. In addition, expression of alloantigen involved in allografts showed similar results in the three substrain. Thus, the results of this study provide strong evidence that C57BL/6NKorl is immunologically similar to two other C57BL/6N substrains.
Collapse
|
5
|
Use of C57BL/6N mice on the variety of immunological researches. Lab Anim Res 2017; 33:119-123. [PMID: 28747977 PMCID: PMC5527137 DOI: 10.5625/lar.2017.33.2.119] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/09/2017] [Accepted: 06/09/2017] [Indexed: 12/11/2022] Open
Abstract
Inbred mice are an essential animal strain for research as they can improve the reproducibility and reliability of study results. The establishment of new inbred lines is continuing, and new inbred lines are being used in many research fields. C57BL/6 is a mouse laboratory animal that has been developed and used as an inbred strain since early stage of mouse strain development, and, in the 1950s, C57BL/6 was separated into substrains by the Jackson Laboratory (C57BL/6J) and the National Institutes of Health (C57BL/6N). C57BL/6 mice have been used in immunology and antitumor activity studies since the early strain development stage. After the mouse genome was fully described, C57BL/6 mice use in many areas of research has expanded. In particular, immunological characteristics such as those related to cell-mediated immunity and NK cell activity are relatively higher in C57BL/6 mice than in other mice. The C57BL/6NKorl is a stock of C57BL/6N established as part of a localization of experimental animal strategy of the Korean Food and Drug Administration. Based on analysis of single nucleotide polymorphisms (SNPs), C57BL/6NKorl is considered a genetically distinct inbred stock from other C57BL/6N. Various research efforts have been made to describe the characteristics and increase knowledge of the characteristics of C57BL/6Nkorl. The results obtained through these efforts are expected to increase the utilization of C57BL/6Nkorl as a domestic laboratory animal resource and to enhance the reliability of mouse based studies.
Collapse
|
6
|
Comparison of humoral and cell-mediated immunity in three different C57BL/6N mouse substrains. Lab Anim Res 2017; 33:132-139. [PMID: 28747979 PMCID: PMC5527139 DOI: 10.5625/lar.2017.33.2.132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/09/2017] [Accepted: 06/09/2017] [Indexed: 11/28/2022] Open
Abstract
Adaptive immunity is a type of immune response mediated by T and B cells, and is important response for immune response amplification and memory. In this study, the adaptive immunologic properties of C57BL/6NKorl substrain were compared with those of two other C57BL/6N substrains. There were no significant differences between the C57BL/6NKorl and the two other C57BL/6N substrains in the histological structures of the thymus and spleen, which are immunologic organs containing T cell and B cells. In addition, flow cytometric analysis did not reveal any significant differences in the distribution of T and B cell populations of the three substrains. To evaluate cell-mediated immunity of T cells in the three different substrains, we treated isolated T cells from spleen with Con A. The T cells of C57BL/6NKorl showed Con A-dependent proliferation of T cells at lower cell number than those in T cells from the other two C57BL/6N substrains. B cell-mediated humoral immune responses were not significant different among the three substrains. Thus, the results of this study provide evidence that C57BL/6NKorl mice are similar to those two other C57BL/6N substrains in humoral immunity, but C57BL/6NKorl has stronger response in cell mediated immunity.
Collapse
|
7
|
Yetman MJ, Lillehaug S, Bjaalie JG, Leergaard TB, Jankowsky JL. Transgene expression in the Nop-tTA driver line is not inherently restricted to the entorhinal cortex. Brain Struct Funct 2015; 221:2231-49. [PMID: 25869275 DOI: 10.1007/s00429-015-1040-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/02/2015] [Indexed: 01/07/2023]
Abstract
The entorhinal cortex (EC) plays a central role in episodic memory and is among the earliest sites of neurodegeneration and neurofibrillary tangle formation in Alzheimer's disease. Given its importance in memory and dementia, the ability to selectively modulate gene expression or neuronal function in the EC is of widespread interest. To this end, several recent studies have taken advantage of a transgenic line in which the tetracycline transactivator (tTA) was placed under control of the neuropsin (Nop) promoter to limit transgene expression within the medial EC and pre-/parasubiculum. Although the utility of this driver is contingent on its spatial specificity, no detailed neuroanatomical analysis of its expression has yet been conducted. We therefore undertook a systematic analysis of Nop-tTA expression using a lacZ reporter and have made the complete set of histological sections available through the Rodent Brain Workbench tTA atlas, www.rbwb.org . Our findings confirm that the highest density of tTA expression is found in the EC and pre-/parasubiculum, but also reveal considerable expression in several other cortical areas. Promiscuous transgene expression may account for the appearance of pathological protein aggregates outside of the EC in mouse models of Alzheimer's disease using this driver, as we find considerable overlap between sites of delayed amyloid deposition and regions with sparse β-galactosidase reporter labeling. While different tet-responsive lines can display individual expression characteristics, our results suggest caution when designing experiments that depend on precise localization of gene products controlled by the Nop-tTA or other spatially restrictive transgenic drivers.
Collapse
Affiliation(s)
- Michael J Yetman
- Departments of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, BCM295, One Baylor Plaza, Houston, TX, 77030, USA
| | - Sveinung Lillehaug
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Jan G Bjaalie
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Trygve B Leergaard
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Joanna L Jankowsky
- Departments of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, BCM295, One Baylor Plaza, Houston, TX, 77030, USA. .,Departments of Neurology and Neurosurgery, Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA.
| |
Collapse
|
8
|
Effect of crossing C57BL/6 and FVB mouse strains on basal cytokine expression. Mediators Inflamm 2015; 2015:762419. [PMID: 25834307 PMCID: PMC4365321 DOI: 10.1155/2015/762419] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 02/09/2015] [Indexed: 11/23/2022] Open
Abstract
C57BL/6 is the most often used laboratory mouse strain. However, sometimes it is beneficial to cross the transgenic mice on the C57BL/6 background to the other strain, such as FVB. Although this is a common strategy, the influence of crossing these different strains on homeostatic expression of cytokines is not known. Here we have investigated the differences in the expression of selected cytokines between C57BL/6J and C57BL/6JxFVB mice in serum and skeletal muscle. We have found that only few cytokines were altered by crossing of the strains. Concentrations of IL5, IL7, LIF, MIP-2, and IP-10 were higher in serum of C57BL/6J mice than in C57BL/6JxFVB mice, whereas concentration of G-CSF was lower in C57BL/6J. In the skeletal muscle only the concentration of VEGF was higher in C57BL/6J mice than in C57BL/6JxFVB mice. Concluding, the differences in cytokine expression upon crossing C57BL/6 and FVB strain in basal conditions are not profound.
Collapse
|
9
|
Tang L, González R, Dobrinski I. Germline modification of domestic animals. Anim Reprod 2015; 12:93-104. [PMID: 27390591 PMCID: PMC4933526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023] Open
Abstract
Genetically-modified domestic animal models are of increasing significance in biomedical research and agriculture. As authentic ES cells derived from domestic animals are not yet available, the prevailing approaches for engineering genetic modifications in those animals are pronuclear microinjection and somatic cell nuclear transfer (SCNT, also known as cloning). Both pronuclear microinjection and SCNT are inefficient, costly, and time-consuming. In animals produced by pronuclear microinjection, the exogenous transgene is usually inserted randomly into the genome, which results in highly variable expression patterns and levels in different founders. Therefore, significant efforts are required to generate and screen multiple founders to obtain animals with optimal transgene expression. For SCNT, specific genetic modifications (both gain-of-function and loss-of-function) can be engineered and carefully selected in the somatic cell nucleus before nuclear transfer. SCNT has been used to generate a variety of genetically modified animals such as goats, pigs, sheep and cattle; however, animals resulting from SCNT frequently suffer from developmental abnormalities associated with incomplete nuclear reprogramming. Other strategies to generate genetically-modified animals rely on the use of the spermatozoon as a natural vector to introduce genetic material into the female gamete. This sperm mediated DNA transfer (SMGT) combined with intracytoplasmatic sperm injection (ICSI) has relatively high efficiency and allows the insertion of large DNA fragments, which, in turn, enhance proper gene expression. An approach currently being developed to complement SCNT for producing genetically modified animals is germ cell transplantation using genetically modified male germline stem cells (GSCs). This approach relies on the ability of GSCs that are genetically modified in vitro to colonize the recipient testis and produce donor derived sperm upon transplantation. As the genetic change is introduced into the male germ line just before the onset of spermatogenesis, the time required for the production of genetically modified sperm is significantly shorter using germ cell transplantation compared to cloning or embryonic stem (ES) cell based technology. Moreover, the GSC-mediated germline modification circumvents problems associated with embryo manipulation and nuclear reprogramming. Currently, engineering targeted mutations in domestic animals using GSCs remains a challenge as GSCs from those animals are difficult to maintain in vitro for an extended period of time. Recent advances in genome editing techniques such as Zinc-Finger Nucleases (ZFNs), Transcription Activator-like Effector Nucleases (TALENs) and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) greatly enhance the efficiency of engineering targeted genetic change in domestic animals as demonstrated by the generation of several gene knock-out pig and cattle models using those techniques. The potential of GSC-mediated germline modification in making targeted genetic modifications in domestic animal models will be maximized if those genome editing techniques can be applied in GSCs.
Collapse
Affiliation(s)
| | | | - I. Dobrinski
- Corresponding author: , Phone: +1(403)210-6523; Fax: +1(403)210-7882
| |
Collapse
|
10
|
Schmidt E, Eriksson M. A previously functional tetracycline-regulated transactivator fails to target gene expression to the bone. BMC Res Notes 2011; 4:282. [PMID: 21835026 PMCID: PMC3169473 DOI: 10.1186/1756-0500-4-282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 08/11/2011] [Indexed: 11/25/2022] Open
Abstract
Background The tetracycline-controlled transactivator system is a powerful tool to control gene expression in vitro and to generate consistent and conditional transgenic in vivo model organisms. It has been widely used to study gene function and to explore pathological mechanisms involved in human diseases. The system permits the regulation of the expression of a target gene, both temporally and quantitatively, by the application of tetracycline or its derivative, doxycycline. In addition, it offers the possibility to restrict gene expression in a spatial fashion by utilizing tissue-specific promoters to drive the transactivator. Findings In this study, we report our problems using a reverse tetracycline-regulated transactivator (rtTA) in a transgenic mouse model system for the bone-specific expression of the Hutchinson-Gilford progeria syndrome mutation. Even though prior studies have been successful utilizing the same rtTA, expression analysis of the transactivator revealed insufficient activity for regulating the transgene expression in our system. The absence of transactivator could not be ascribed to differences in genetic background because mice in a mixed genetic background and in congenic mouse lines showed similar results. Conclusions The purpose of this study is to report our negative experience with previously functional transactivator mice, to raise caution in the use of tet-based transgenic mouse lines and to reinforce the need for controls to ensure the stable functionality of generated tetracycline-controlled transactivators over time.
Collapse
Affiliation(s)
- Eva Schmidt
- Department of Biosciences and Nutrition, Center for Biosciences, Karolinska Institutet, Karolinska University Hospital, Huddinge, Novum, SE-14183 Stockholm, Sweden.
| | | |
Collapse
|
11
|
Piedrahita JA, Olby N. Perspectives on transgenic livestock in agriculture and biomedicine: an update. Reprod Fertil Dev 2011; 23:56-63. [PMID: 21366981 DOI: 10.1071/rd10246] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
It has been 30 years since the first transgenic mouse was generated and 26 years since the first example of transferring the technology to livestock was published. While there was tremendous optimism in those initial years, with most convinced that genetically modified animals would play a significant role in agricultural production, that has not come to be. So at first sight one could conclude that this technology has, to a large extent, failed. On the contrary, it is believed that it has succeeded beyond our original expectations, and we are now at what is perhaps the most exciting time in the development and implementation of these technologies. The original goals, however, have drastically changed and it is now biomedical applications that are playing a central role in pushing both technical and scientific developments. The combination of advances in somatic cell nuclear transfer, the development of induced pluripotent stem cells and the completion of the sequencing of most livestock genomes ensures a bright and exciting future for this field, not only in livestock but also in companion animal species.
Collapse
Affiliation(s)
- Jorge A Piedrahita
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27606, USA.
| | | |
Collapse
|
12
|
Selection against Robertsonian fusions involving housekeeping genes in the house mouse: integrating data from gene expression arrays and chromosome evolution. Chromosome Res 2010; 18:801-8. [DOI: 10.1007/s10577-010-9153-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 08/03/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022]
|
13
|
Abstract
In generating a conditional transgenic murine model based on a tetracycline-regulated system, we obtained unexpected patterns of expression due to the transcriptional inactivity of the tet-responder promoter. Here we show strong cell-type-restricted expression that was variegated to an extent determined by the number of responder transgene copies integrated into the host genome.
Collapse
|
14
|
Calzascia T, Loh JMS, Di Berardino-Besson W, Masson F, Guillaume P, Burkhardt K, Herrera PL, Dietrich PY, Walker PR. Peripheral tolerance limits CNS accumulation of CD8 T cells specific for an antigen shared by tumor cells and normal astrocytes. Glia 2008; 56:1625-36. [DOI: 10.1002/glia.20715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
15
|
Shin SS, Kim TM, Kim SY, Kim TW, Seo HW, Lee SK, Kwon SC, Lee GS, Kim H, Lim JM, Han JY. Generation of transgenic quail through germ cell-mediated germline transmission. FASEB J 2008; 22:2435-44. [PMID: 18263695 DOI: 10.1096/fj.07-101485] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Here, we describe the production of transgenic quail via a germline transmission system using postmigratory gonadal primordial germ cells (gPGCs). gPGCs retrieved from the embryonic gonads of 5-day-old birds were transduced with a lentiviral vector and subsequently transferred into recipient embryos. Testcross and genetic analyses revealed that among three germline chimeric G0 quail, one male produced transgenic offspring; of 310 hatchlings from the transgenic germline chimera, 24 were identified as donor-derived offspring, and 6 were transgenic (6/310, 1.9%). Conventional transgenesis using stage X blastodermal embryos was also conducted, but the efficiency of transgenesis was similar between the two systems (<1.6 vs. 1.9% for the conventional and gPGC-mediated systems, respectively). However, substantial advantages can be gained from gPGC-mediated method in that it enables an induced germline modification, whereas direct retroviral transfer to stage X embryos causes mosaic integration. The use of gonadal PGCs for transgenesis may lead to the production of bioreactors.
Collapse
Affiliation(s)
- Sang Su Shin
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Marenkova (Novoselia) TV, Deineko EV, Shumny VK. Mosaic expression pattern of the nptII gene in transgenic tobacco plants Nu 21. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407070101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
17
|
Eckenstein FP, McGovern T, Kern D, Deignan J. Neuronal vulnerability in transgenic mice expressing an inducible dominant-negative FGF receptor. Exp Neurol 2006; 198:338-49. [PMID: 16487970 DOI: 10.1016/j.expneurol.2005.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2005] [Revised: 11/28/2005] [Accepted: 12/01/2005] [Indexed: 10/25/2022]
Abstract
Fibroblast Growth Factors (FGFs) and their receptors (FGFRs) are widely expressed in the mature nervous system and are thought to mediate plasticity and repair. We report the generation of transgenic mice that can be induced to express a dominant-negative FGFR (dnFGFR) in select neuronal populations. We show that a modified Thy1 promoter [Vidal, M., Morris, R., Grosveld, F., and Spanopoulou, E. 1990. Tissue-specific control elements of the Thy-1 gene. EMBO J 9 833-840] can be used to drive widespread neuronal expression of the reverse tetracycline transactivator M2 (rtTA-M2 [Urlinger, S., Baron, U., Thellmann, M., Hasan, M.T., Bujard, H., and Hillen, W., 2000. Exploring the sequence space for tetracycline-dependent transcriptional activators: novel mutations yield expanded range and sensitivity. Proc. Natl. Acad. Sci. U. S. A. 97, 7963-7968]), which after stimulation with doxycycline induces co-expression of dnFGFR in mosaic subpopulations of rtTA-M2-positive forebrain neurons, but not in hindbrain and spinal cord rtTA-M2-positive neurons. Expression of dnFGFR did not cause overt neurodegeneration, but led to increased neuronal vulnerability: four days after a stab injury, cell death was marked in the hippocampus of dnFGFR-expressing animals when compared to controls. The nuclear morphology of dying CA1 pyramidal cells suggested an apoptotic mechanism of cell death. These observations demonstrate the importance of endogenous FGFs in the maintenance of the nervous system.
Collapse
Affiliation(s)
- Felix P Eckenstein
- Department of Neurology and Department of Anatomy and Neurobiology, College of Medicine, University of Vermont, HSRF 408, VT 05405, USA.
| | | | | | | |
Collapse
|
18
|
Kramer BA, Lemckert FA, Alexander IE, Gunning PW, McCowage GB. Characterisation of a P140K mutantO6-methylguanine-DNA-methyltransferase (MGMT)-expressing transgenic mouse line with drug-selectable bone marrow. J Gene Med 2006; 8:1071-85. [PMID: 16927363 DOI: 10.1002/jgm.937] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Gene transfer of the P140K mutant of O6-methylguanine-DNA-methyltransferase (MGMT(P140K)) into hematopoietic stem cells (HSC) provides a mechanism for drug resistance and the selective expansion of gene-modified cells in vivo. Possible clinical applications for this strategy include chemoprotection to allow dose escalation of alkylating chemotherapy, or combining MGMT(P140K) expression with a therapeutic gene in the treatment of genetic diseases. Our aim is to use MGMT(P140K)-driven in vivo selection to develop allogeneic micro-transplantation protocols that rely on post-engraftment selection to overcome the requirement for highly toxic pre-transplant conditioning, and to establish and maintain predictable levels of donor/recipient chimerism. METHODS Using stably transfected murine embryonic stem (ES) cells, we have generated a C57BL/6 transgenic mouse line with expression of MGMT(P140K) within the hematopoietic compartment for use as a standard source of donor HSC in such models. Functional characterisation of transgene expression was carried out in chemotherapy-treated transgenic mice and in allogeneic recipients of transgenic HSC. RESULTS Expression of the transgene provided chemoprotection and allowed in vivo selection of MGMT(P140K)-expressing cells in transgenic mice after exposure to O6-benzylguanine (BG) and N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU). In an allogeneic transplant experiment in which transgenic HSC were engrafted into 129 strain recipients following low intensity conditioning (Busulfan, anti-CD8, anti-CD40Ligand), MGMT(P140K)-expressing cells could be selected using chemotherapy. CONCLUSIONS This MGMT(P140K) transgenic mouse line provides a useful source of drug-selectable donor cells for the development of non-myeloablative allogeneic transplant models in which variation in transplant conditioning elements can be investigated independently of gene transfer efficiency.
Collapse
Affiliation(s)
- Belinda A Kramer
- Oncology Research Unit, The Children's Hospital at Westmead, and Discipline of Paediatric and Child Health, University of Sydney, NSW, Australia.
| | | | | | | | | |
Collapse
|
19
|
Abstract
Characterization of genetically engineered mice requires consideration of the gene of interest and the genetic background on which the mutation is maintained. A fundamental prerequisite to deciphering the genetic factors that influence the phenotype of a mutant mouse is an understanding of genetic nomenclature. Mutations and transgenes are often maintained on segregating or mixed backgrounds of often-unspecified origin. Minimizing the importance of strain and substrain differences, especially among 129 strains, can lead to poor experimental design or faulty interpretations of data. Genetic factors that influence phenotype can be categorized as traits that are unique to the background strain, unique to the gene of interest, or an interaction of both the background strain and the gene of interest. The commonly used inbred strains are generally well characterized and understood; however, specific genetic alterations combined with genes unique to the background inbred strain may lead to unexpected results. Genetic background effects can be analyzed and controlled for by using specific targeting and breeding strategies. Selection of appropriate experimental controls is critical. Ideally, mutations or transgenes should be characterized on more than one genetic background and in hybrids of the two progenitor strains. This approach may lead to the identification of novel genetic modifiers of the "gene of interest." Conditional mutagenesis technologies increase the options for controlling genetic background effects in addition to permitting the study of developmental and temporal changes in gene and protein expression and thus phenotype.
Collapse
Affiliation(s)
- Carol Cutler Linder
- Department of Natural Sciences, New Mexico Highlands University, Las Vegas, New Mexico, USA
| |
Collapse
|
20
|
Kucharzik T, Hudson JT, Lügering A, Abbas JA, Bettini M, Lake JG, Evans ME, Ziegler TR, Merlin D, Madara JL, Williams IR. Acute induction of human IL-8 production by intestinal epithelium triggers neutrophil infiltration without mucosal injury. Gut 2005; 54:1565-72. [PMID: 15987794 PMCID: PMC1774758 DOI: 10.1136/gut.2004.061168] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 06/01/2005] [Accepted: 06/03/2005] [Indexed: 12/19/2022]
Abstract
AIM Neutrophil migration in the intestine depends on chemotaxis of neutrophils to CXC chemokines produced by epithelial cells. The goal of this project was to determine if acute induction of a CXC chemokine gradient originating from intestinal epithelial cells is sufficient to induce neutrophil influx into intact intestinal tissue. METHODS AND RESULTS The authors developed a double transgenic mouse model with doxycycline induced human IL-8 expression restricted to intestinal epithelial cells. Doxycycline treatment of double transgenic mice for three days resulted in a 50-fold increase in the caecal IL-8 concentration and influx of neutrophils into the lamina propria. Although neutrophils entered the paracellular space between epithelial cells, complete transepithelial migration was not observed. Doxycycline treatment also increased the water content of the caecal and colonic stool, indicating dysfunctional water transport. However, the transmural electrical resistance was not decreased. Neutrophils recruited to the intestinal epithelium did not show evidence of degranulation and the epithelium remained intact as judged by histology. CONCLUSIONS This conditional transgenic model of chemokine expression provides evidence that acute induction of IL-8 in the intestinal epithelium is sufficient to trigger neutrophil recruitment to the lamina propria, but additional activation signals are needed for full activation and degranulation of neutrophils, mucosal injury, and complete transepithelial migration.
Collapse
Affiliation(s)
- T Kucharzik
- Department of Pathology, Emory University, 105D Whitehead Building, 615 Michael Street, Atlanta, GA 30322, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Donovan DM, Kerr DE, Wall RJ. Engineering Disease Resistant Cattle. Transgenic Res 2005; 14:563-7. [PMID: 16245147 DOI: 10.1007/s11248-005-0670-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 06/21/2005] [Indexed: 11/25/2022]
Abstract
Mastitis is a disease of the mammary gland caused by pathogens that find their way into the lumen of the gland through the teat canal. Mammary gland infections cost the US dairy industry approximately $2 billion dollars annually and have a similar impact in Europe. In the absence of effective treatments or breeding strategies to enhance mastitis resistance, we have created transgenic dairy cows that express lysostaphin in their mammary epithelium and secrete the antimicrobial peptide into milk. Staphylococcus aureus, a major mastitis pathogen, is exquisitely sensitive to lysostaphin. The transgenic cattle resist S. aureus mammary gland challenges, and their milk kills the bacteria, in a dose dependent manner. This first step in protecting cattle against mastitis will be followed by introduction of other genes to deal with potential resistance issues and other mastitis causing organisms. Care will be taken to avoid altering milk's nutritional and manufacturing properties. Multi-cistronic constructs may be required to achieve our goals as will other strategies possibly involving RNAi and gene targeting technology. This work demonstrates the possibility of using transgenic technology to address disease problems in agriculturally important species.
Collapse
Affiliation(s)
- David M Donovan
- Biotechnology and Germplasm Laboratory, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705, USA
| | | | | |
Collapse
|
22
|
Kamihira M, Ono KI, Esaka K, Nishijima KI, Kigaku R, Komatsu H, Yamashita T, Kyogoku K, Iijima S. High-level expression of single-chain Fv-Fc fusion protein in serum and egg white of genetically manipulated chickens by using a retroviral vector. J Virol 2005; 79:10864-74. [PMID: 16103139 PMCID: PMC1193598 DOI: 10.1128/jvi.79.17.10864-10874.2005] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2005] [Accepted: 05/24/2005] [Indexed: 01/29/2023] Open
Abstract
We report here the generation of transgenic chickens using a retroviral vector for the production of recombinant proteins. It was found that the transgene expression was suppressed when a Moloney murine leukemia virus-based retroviral vector was injected into chicken embryos at the blastodermal stage. When a concentrated viral solution was injected into the heart of developing embryos after 50 to 60 h of incubation, transgene expression was observed throughout the embryo, including the gonads. For practical production, a retroviral vector encoding an expression cassette of antiprion single-chain Fv fused with the Fc region of human immunoglobulin G1 (scFv-Fc) was injected into chicken embryos. The birds that hatched stably produced scFv-Fc in their serum and eggs at high levels (approximately 5.6 mg/ml). We obtained transgenic progeny from a transgenic chicken generated with this procedure. The transgene was stably integrated into the chromosomes of transgenic progeny. The transgenic progeny also expressed scFv-Fc in the serum and eggs.
Collapse
Affiliation(s)
- Masamichi Kamihira
- Department of Biotechnology, Graduate School of Engineering, Nagoya University, Chikusa-ku, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Diagnosis | Mammary adenocarcinoma due to atypical expression of TRAMP transgene. Lab Anim (NY) 2005. [DOI: 10.1038/laban0405-32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
24
|
Good AG, Shrawat AK, Muench DG. Can less yield more? Is reducing nutrient input into the environment compatible with maintaining crop production? TRENDS IN PLANT SCIENCE 2004; 9:597-605. [PMID: 15564127 DOI: 10.1016/j.tplants.2004.10.008] [Citation(s) in RCA: 334] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plant scientists have long recognized the need to develop crops that absorb and use nutrients more efficiently. Two approaches have been used to increase nutrient use efficiency (NUE) in crop plants. The first involves both traditional breeding and marker-assisted selection in an attempt to identify the genes involved. The second uses novel gene constructs designed to improve specific aspects of NUE. Here, we discuss some recent developments in the genetic manipulation of NUE in crop plants and argue that an improved understanding of the transition between nitrogen assimilation and nitrogen recycling will be important in applying this technology to increasing crop yields. Moreover, we emphasize the need to combine genetic and transgenic approaches to make significant improvements in NUE.
Collapse
Affiliation(s)
- Allen G Good
- Department of Biological Sciences, G-425, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
| | | | | |
Collapse
|
25
|
Whitelaw CBA, Hiripi L, Farini E, Opsahl ML, Bosze Z. On the use of post-transcriptional processing elements in transgenes. Transgenic Res 2004; 13:75-9. [PMID: 15070078 PMCID: PMC7089212 DOI: 10.1023/b:trag.0000017178.79427.2c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
RNA processing events modulate final productivity of a given transgene. We have evaluated a series of RNA elements for their ability to enhance α1-antitrypsin production in mammary cells. Our results indicate the need for a case-by-case assessment of each construct design and the occurrence of gene silencing events in vivo.
Collapse
Affiliation(s)
- C B A Whitelaw
- Department of Gene Expression and Development, Roslin Institute (Edinburgh), Roslin, Midlothian, EH25 9PS, UK.
| | | | | | | | | |
Collapse
|