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Brown DM, Glass JI. Technology used to build and transfer mammalian chromosomes. Exp Cell Res 2020; 388:111851. [PMID: 31952951 DOI: 10.1016/j.yexcr.2020.111851] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/09/2020] [Accepted: 01/14/2020] [Indexed: 01/05/2023]
Abstract
In the near twenty-year existence of the human and mammalian artificial chromosome field, the technologies for artificial chromosome construction and installation into desired cell types or organisms have evolved with the rest of modern molecular and synthetic biology. Medical, industrial, pharmaceutical, agricultural, and basic research scientists seek the as yet unrealized promise of human and mammalian artificial chromosomes. Existing technologies for both top-down and bottom-up approaches to construct these artificial chromosomes for use in higher eukaryotes are very different but aspire to achieve similar results. New capacity for production of chromosome sized synthetic DNA will likely shift the field towards more bottom-up approaches, but not completely. Similarly, new approaches to install human and mammalian artificial chromosomes in target cells will compete with the microcell mediated cell transfer methods that currently dominate the field.
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2
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Brown DM, Chan YA, Desai PJ, Grzesik P, Oldfield LM, Vashee S, Way JC, Silver PA, Glass JI. Efficient size-independent chromosome delivery from yeast to cultured cell lines. Nucleic Acids Res 2017; 45:e50. [PMID: 27980064 PMCID: PMC5397165 DOI: 10.1093/nar/gkw1252] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/13/2016] [Indexed: 01/04/2023] Open
Abstract
The delivery of large DNA vectors (>100 000 bp) remains a limiting step in the engineering of mammalian cells and the development of human artificial chromosomes (HACs). Yeast is commonly used to assemble genetic constructs in the megabase size range, and has previously been used to transfer constructs directly into cultured cells. We improved this method to efficiently deliver large (1.1 Mb) synthetic yeast centromeric plasmids (YCps) to cultured cell lines at rates similar to that of 12 kb YCps. Synchronizing cells in mitosis improved the delivery efficiency by 10-fold and a statistical design of experiments approach was employed to boost the vector delivery rate by nearly 300-fold from 1/250 000 to 1/840 cells, and subsequently optimize the delivery process for multiple mammalian, avian, and insect cell lines. We adapted this method to rapidly deliver a 152 kb herpes simplex virus 1 genome cloned in yeast into mammalian cells to produce infectious virus.
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Affiliation(s)
- David M Brown
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, Rockville, MD, 20850, USA.,Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Yujia A Chan
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.,Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Prashant J Desai
- Johns Hopkins University, Sidney Kimmel Comprehensive Cancer Center Johns Hopkins, Viral Oncology Program, Baltimore, MD 21231, USA
| | - Peter Grzesik
- Johns Hopkins University, Sidney Kimmel Comprehensive Cancer Center Johns Hopkins, Viral Oncology Program, Baltimore, MD 21231, USA
| | - Lauren M Oldfield
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, Rockville, MD, 20850, USA
| | - Sanjay Vashee
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, Rockville, MD, 20850, USA
| | - Jeffrey C Way
- Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Pamela A Silver
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.,Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - John I Glass
- Synthetic Biology and Bioenergy, J. Craig Venter Institute, Rockville, MD, 20850, USA
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3
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Brüggemann M, Osborn MJ, Ma B, Hayre J, Avis S, Lundstrom B, Buelow R. Human antibody production in transgenic animals. Arch Immunol Ther Exp (Warsz) 2014; 63:101-8. [PMID: 25467949 PMCID: PMC4359279 DOI: 10.1007/s00005-014-0322-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 11/19/2014] [Indexed: 11/26/2022]
Abstract
Fully human antibodies from transgenic animals account for an increasing number of new therapeutics. After immunization, diverse human monoclonal antibodies of high affinity can be obtained from transgenic rodents, while large animals, such as transchromosomic cattle, have produced respectable amounts of specific human immunoglobulin (Ig) in serum. Several strategies to derive animals expressing human antibody repertoires have been successful. In rodents, gene loci on bacterial artificial chromosomes or yeast artificial chromosomes were integrated by oocyte microinjection or transfection of embryonic stem (ES) cells, while ruminants were derived from manipulated fibroblasts with integrated human chromosome fragments or human artificial chromosomes. In all strains, the endogenous Ig loci have been silenced by gene targeting, either in ES or fibroblast cells, or by zinc finger technology via DNA microinjection; this was essential for optimal production. However, comparisons showed that fully human antibodies were not as efficiently produced as wild-type Ig. This suboptimal performance, with respect to immune response and antibody yield, was attributed to imperfect interaction of the human constant region with endogenous signaling components such as the Igα/β in mouse, rat or cattle. Significant improvements were obtained when the human V-region genes were linked to the endogenous CH-region, either on large constructs or, separately, by site-specific integration, which could also silence the endogenous Ig locus by gene replacement or inversion. In animals with knocked-out endogenous Ig loci and integrated large IgH loci, containing many human Vs, all D and all J segments linked to endogenous C genes, highly diverse human antibody production similar to normal animals was obtained.
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Affiliation(s)
- Marianne Brüggemann
- Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge CB22 3AT UK
- Open Monoclonal Technology, Inc., Palo Alto, CA 94303 USA
| | - Michael J. Osborn
- Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge CB22 3AT UK
| | - Biao Ma
- Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge CB22 3AT UK
| | - Jasvinder Hayre
- Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge CB22 3AT UK
| | - Suzanne Avis
- Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge CB22 3AT UK
| | | | - Roland Buelow
- Open Monoclonal Technology, Inc., Palo Alto, CA 94303 USA
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4
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Osborn MJ, Ma B, Avis S, Binnie A, Dilley J, Yang X, Lindquist K, Ménoret S, Iscache AL, Ouisse LH, Rajpal A, Anegon I, Neuberger MS, Buelow R, Brüggemann M. High-affinity IgG antibodies develop naturally in Ig-knockout rats carrying germline human IgH/Igκ/Igλ loci bearing the rat CH region. THE JOURNAL OF IMMUNOLOGY 2013; 190:1481-90. [PMID: 23303672 DOI: 10.4049/jimmunol.1203041] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mice transgenic for human Ig loci are an invaluable resource for the production of human Abs. However, such mice often do not yield human mAbs as effectively as conventional mice yield mouse mAbs. Suboptimal efficacy in delivery of human Abs might reflect imperfect interaction between the human membrane IgH chains and the mouse cellular signaling machinery. To obviate this problem, in this study we generated a humanized rat strain (OmniRat) carrying a chimeric human/rat IgH locus (comprising 22 human V(H)s, all human D and J(H) segments in natural configuration linked to the rat C(H) locus) together with fully human IgL loci (12 Vκs linked to Jκ-Cκ and 16 Vλs linked to Jλ-Cλ). The endogenous Ig loci were silenced using designer zinc finger nucleases. Breeding to homozygosity resulted in a novel transgenic rat line exclusively producing chimeric Abs with human idiotypes. B cell recovery was indistinguishable from wild-type animals, and human V(D)J transcripts were highly diverse. Following immunization, the OmniRat strain performed as efficiently as did normal rats in yielding high-affinity serum IgG. mAbs, comprising fully human variable regions with subnanomolar Ag affinity and carrying extensive somatic mutations, are readily obtainable, similarly to conventional mAbs from normal rats.
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Affiliation(s)
- Michael J Osborn
- Recombinant Antibody Technology Ltd., Babraham Research Campus, Babraham, Cambridge CB22 3AT, United Kingdom
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5
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Silverman GA. Building larger YACs by recombination. CURRENT PROTOCOLS IN HUMAN GENETICS 2008; Chapter 5:Unit 5.13. [PMID: 18428287 DOI: 10.1002/0471142905.hg0513s05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Despite the relatively large cloning capacity of YACs, many genomic regions or individual genes are not cloned intact, but are represented as a collection of overlapping clones or contigs. Fortunately, the relatively high frequency and fidelity of homologous recombination in Saccharomyces cerevisiae can be used to reconstruct intact genes within a single clone by splicing together overlapping DNA segments. This unit describes two protocols for carrying out such homologous recombination; one relies on the meiotic phase of the yeast cycle, while the other utilizes the mitotic phase of the yeast life cycle. Despite the relatively large cloning capacity of YACs, many genomic regions or individual genes are not cloned intact.
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Affiliation(s)
- G A Silverman
- Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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6
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Abstract
Exon 9 of the human gene CFTR is skipped in some mRNA transcripts in human tissues. The level of skipping correlates with the number of TG's and T's in the 5' splice acceptor of exon 9. Poorly spliced alleles are associated with mild cystic fibrosis related phenotypes. Here we describe transgenic mice carrying a yeast artificial chromosome (YAC) with the intact human gene CFTR. When the YAC carries 10 TG's and 7 T's at the splice acceptor, there is about 50% skipping of exon 9 in most tissues, whereas 12 TG's and 5 T's give about 90% skipping. The level of skipping is quite uniform over many tissues, except the testis, in which there is a much higher level of correct splicing. These mice confirm that the TG(m)T(n) polymorphism has an effect on splicing and should be valuable for studying this phenomenon.
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Affiliation(s)
- A Manson
- Faculty of Medicine, Imperial College School of Science, Technology and Medicine, London, SW7 2AZ, UK
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7
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Wilson CJ, Guglielmo C, Moua ND, Tudor M, Grosveld G, Young RA, Murray PJ. Yeast artificial chromosome targeting technology: an approach for the deletion of genes in the C57BL/6 mouse. Anal Biochem 2001; 296:270-8. [PMID: 11554723 DOI: 10.1006/abio.2001.5304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An approach is described to modify yeast artificial chromosomes (YACs) with cassettes that can be easily excised for embryonic stem (ES) cell gene targeting experiments. YAC targeting technology (YTT) uses the WIBR/MIT-820 C57BL/6-mapped YAC library derived from the C57BL/6 mouse as the starting point for Internet- or PCR-based clone isolation, although in principle any YAC system can be used. Homologous recombination is initially performed in yeast using cassettes that function in Saccharomyces cerevisiae, Escherichia coli, and ES cells, followed by cloning or conversion of the targeted locus into a plasmid. The completed targeting vector can be transfected into C57BL/6 ES cells and clones selected with G418 followed by injection into Balb/c blastocysts. YTT increases the speed of targeting vector construction and obviates the need for extensive backcrossing to the C57BL/6 background.
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Affiliation(s)
- C J Wilson
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, Massachusetts 02142, USA
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8
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Nicholson IC, Zou X, Popov AV, Cook GP, Corps EM, Humphries S, Ayling C, Goyenechea B, Xian J, Taussig MJ, Neuberger MS, Brüggemann M. Antibody Repertoires of Four- and Five-Feature Translocus Mice Carrying Human Immunoglobulin Heavy Chain and κ and λ Light Chain Yeast Artificial Chromosomes. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.12.6898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
We have produced mice that carry the human Ig heavy (IgH) and both κ and λ light chain transloci in a background in which the endogenous IgH and κ loci have been inactivated. The B lymphocyte population in these translocus mice is restored to about one-third of normal levels, with preferential (3:1) expression of human λ over human κ. Human IgM is found in the serum at levels between 50 and 400 μg/ml and is elevated following immunization. This primary human Ab repertoire is sufficient to yield diverse Ag-specific responses as judged by analysis of mAbs. The use of DH and J segments is similar to that seen in human B cells, with an analogous pattern of N nucleotide insertion. Maturation of the response is accompanied by somatic hypermutation, which is particularly effective in the light chain transloci. These mice therefore allow the production of Ag-specific repertoires of both IgM,κ and IgM,λ Abs and should prove useful for the production of human mAbs for clinical use.
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Affiliation(s)
| | | | | | - Graham P. Cook
- ‡Laboratory of Molecular Biology, Medical Research Council, Cambridge, United Kingdom
| | - Elaine M. Corps
- †Laboratory of Molecular Recognition, The Babraham Institute, Babraham, Cambridge, United Kingdom; and
| | - Sally Humphries
- †Laboratory of Molecular Recognition, The Babraham Institute, Babraham, Cambridge, United Kingdom; and
| | | | | | - Jian Xian
- *Laboratory of Developmental Immunology and
| | - Michael J. Taussig
- †Laboratory of Molecular Recognition, The Babraham Institute, Babraham, Cambridge, United Kingdom; and
| | - Michael S. Neuberger
- ‡Laboratory of Molecular Biology, Medical Research Council, Cambridge, United Kingdom
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9
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Nuthall HN, Vassaux G, Huxley C, Harris A. Analysis of a DNase I hypersensitive site located -20.9 kb upstream of the CFTR gene. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 266:431-43. [PMID: 10561583 DOI: 10.1046/j.1432-1327.1999.00872.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator gene (CFTR) shows a tightly regulated pattern of expression with spatial and temporal control. The regulatory elements achieving this appear to lie outside the basal promoter of the gene. We previously identified DNase I hypersensitive sites (DHSs) at -79.5 kb and -20.5 kb with respect to the CFTR translational start site which may contain important regulatory elements. We have now investigated further the DHS at -20.5 kb to evaluate its potential function in the regulation of CFTR expression. Finer mapping revealed that the DHS lies at -20.9 kb. Deletion of the DHS from a 310-kb yeast artificial chromosome (YAC) containing the human CFTR gene has shown that this site may be responsible for about 60% of wild-type levels of transcription from the YAC transgene when expressed in Caco2 cells. DNase I footprinting showed several regions of protection within the -20.9 kb region with nuclear extracts from Caco2 cells, but not with extracts from lymphoblastoid cells, which do not show the DHS. Matches to several transcription factor-binding sites were found, but supershift analysis with specific antibodies did not identify the transcription factors involved. Two purine/pyrimidine mirror repeat elements within the -20.9-kb DHS were shown not to adopt non-B-DNA conformations. Thus, we provide evidence for a role for the -20.9 kb DHS in the transcriptional regulation of the CFTR gene, although the mechanisms mediating this effect remain unclear.
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MESH Headings
- Amino Acid Motifs
- Base Sequence
- Binding Sites
- Chromosomes, Artificial, Yeast
- Cloning, Molecular
- Cystic Fibrosis Transmembrane Conductance Regulator/chemistry
- Cystic Fibrosis Transmembrane Conductance Regulator/genetics
- DNA, Superhelical/ultrastructure
- Deoxyribonuclease I/chemistry
- Electrophoresis, Agar Gel
- Exons
- Gene Deletion
- Gene Expression Regulation
- Humans
- Models, Genetic
- Molecular Sequence Data
- Nucleic Acid Conformation
- Plasmids/metabolism
- Protein Biosynthesis
- Purines/chemistry
- Pyrimidines/chemistry
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Single-Strand Specific DNA and RNA Endonucleases/metabolism
- Transcription, Genetic
- Transgenes
- Tumor Cells, Cultured
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Affiliation(s)
- H N Nuthall
- Paediatric Molecular Genetics, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
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10
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Fabb SA, Ragoussis J. Yeast artificial chromosome vectors. MOLECULAR AND CELL BIOLOGY OF HUMAN DISEASES SERIES 1998; 5:104-24. [PMID: 9532563 DOI: 10.1007/978-94-011-0547-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- S A Fabb
- Division of Medical and Molecular Genetics, UMDS Guy's Hospital, London, UK
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11
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Huxley C. Exploring gene function: use of yeast artificial chromosome transgenesis. Methods 1998; 14:199-210. [PMID: 9571077 DOI: 10.1006/meth.1997.0578] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Transgenesis is a very powerful tool in functional analysis of proteins and control of gene expression. One of the main drawbacks has been the low levels of expression, lack of tissue specificity, and inappropriate expression frequently observed for transgenes made with small plasmid-based constructs. The use of much larger DNA fragments cloned in yeast artificial clones (YACs), bacterial artificial clones, or P1-based artificial clones has been found to give much better levels of expression, generally very close to that of an endogenous gene, and tissue-specific expression matching that of the endogenous gene. In addition, the large DNA can easily be subtly modified by homologous recombination. This article describes the background and methods of YAC transgenesis.
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Affiliation(s)
- C Huxley
- Department of Biochemistry and Molecular Genetics, Imperial College School of Medicine at St. Mary's, London, United Kingdom
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12
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Zweigerdt R, Braun T, Arnold HH. Faithful expression of the Myf-5 gene during mouse myogenesis requires distant control regions: a transgene approach using yeast artificial chromosomes. Dev Biol 1997; 192:172-80. [PMID: 9405106 DOI: 10.1006/dbio.1997.8759] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Myf-5, a member of the family of four muscle-specific basic helix-loop-helix (bHLH) transcription factors is the first to be expressed in somites, branchial arches, and limb buds during prenatal mouse development. However, little is known about control mechanisms which actually regulate Myf-5 gene activity within these various muscle-forming domains. To identify control regions that contribute to the correct spatiotemporal activity pattern of the Myf-5 gene during mouse embryogenesis, here we report the characterization of yeast artificial chromosomes (YACs) which faithfully direct muscle-specific expression of the gene in chimeric mouse embryos. Forty-five kilobases of sequence 5' to the Myf-5 gene together with 500 kb of 3' flanking DNA drives the correct Myf-5 expression in the mesenchyme of the visceral arches and in somites but not in the hypaxial muscles of limb buds. An additional 50 kb of DNA at the 5' end is required to activate Myf-5 gene expression in developing limbs. These results demonstrate for the first time that unexpectedly distant regions of the Myf-5 gene are necessary to recapitulate its precise developmental expression pattern. We also show that Myf-5 expression in hypaxial muscles and in somites and visceral arches is regulated by separate and distinct far upstream regions. The identification of these remote regulatory elements on YACs carrying the mouse Myf-5 gene constitutes the first important step toward further dissection of the complex mechanisms by which cell-autonomous and external cues control Myf-5 expression during skeletal muscle formation in the mouse embryo.
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Affiliation(s)
- R Zweigerdt
- Department of Cell and Molecular Biology, University of Braunschweig, Spielmannstr. 7, Braunschweig, 38106, Federal Republic of Germany
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13
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Tucker RM, Burke DT. Two vectors for the insertion of mammalian selectable genes into yeast artificial chromosome cloned DNA. Gene X 1997; 199:25-30. [PMID: 9358035 DOI: 10.1016/s0378-1119(97)00306-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The introduction of cloned DNA into mammalian cells allows functional testing of genes contained on the fragments. In many cases, the exogenous DNA introduced into mammalian cells requires selectable genes that mark the presence of input DNA. Two new vectors, carrying mammalian selectable markers encoding for either neomycin-resistance (neo) or histidinol-resistance (hol), have been constructed for targeted integration to specific single-copy sites within yeast artificial chromosome (YAC) insert DNA. The integration cassettes comprise a single selectable yeast gene adjacent to a mammalian selectable gene, either LEU2 with neo or HIS3 with hol. Modification of the YAC occurs in yeast by transfection with linear DNA containing YAC-specific, unique, recombinogenic ends, thereby ensuring co-integration of the markers. Analysis of modified YACs confirms that both vectors correctly integrate into the targeted unique sites. The precise localization of selectable marker genes in the cloned DNA ensures the integrity of the genomic fragments during functional testing. Placement of mammalian selectable markers within the YAC insert DNA should allow for YAC-based gene targeting experiments in a variety of mammalian cell lines.
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Affiliation(s)
- R M Tucker
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor 48109, USA
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14
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Abstract
A novel strategy for separation of co-cloned YACs was developed. For this, yeast cells were grown under non-selective conditions to allow the mitotic loss of multiple YACs. Yeast colonies of different size appear on 'drop-out' selection plates with small clones consistently containing a single-copy YAC. Different auxotrophic marker genes can be used to separate co-cloned YACs or reduce their copy number, which is essential for most YAC-modification procedures.
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Affiliation(s)
- A V Popov
- Department of Development and Genetics, The Babraham Institute, Cambridge CB2 4AT, UK.
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15
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Popov AV, Bützler C, Frippiat JP, Lefranc MP, Brüggemann M. Assembly and extension of yeast artificial chromosomes to build up a large locus. Gene 1996; 177:195-201. [PMID: 8921867 DOI: 10.1016/0378-1119(96)00301-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
For the assembly of a large human locus, overlapping regions on yeast artificial chromosomes (YACs) and cosmids were linked up using their regions of homology. By site-specific recombination a YAC of 410 kb was created accommodating the major part of the human lambda light chain locus in authentic configuration with 28 variable (V) genes, all joining (J) segments, all constant (C) genes and the downstream enhancer. A contiguous region was first constructed from three overlapping cosmids. Each of these was linearized at unique sites in the vectors and YAC arms were ligated to the 5' and 3' ends. After cells of Saccharomyces cerevisiae were transformed with the three cosmids, YACs of 120 kb were obtained which contained the reassembled 3' J-C region in authentic configuration. The assembled YAC was further extended by mitotic recombination with a YAC containing a 280-kb region of the C-proximal part of the V gene cluster with a 15-kb 3' overlap. For this, a simple three-way selection procedure was developed involving the integration of different selectable marker genes at specific sites in the left and right YAC arms. Rare recombination events between two overlapping YACs could be identified in yeast clones able to grow in lysine- and adenine-deficient medium in the presence of 5-fluoro-orotic acid which is toxic for yeast cells containing a YAC with a functional URA3 gene. This approach made it possible to assemble and extend large YACs from an unlimited number of smaller overlapping YACs by positive-negative selection.
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Affiliation(s)
- A V Popov
- Department of Development and Genetics, Babraham Institute, Cambridge, UK.
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16
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Brüggemann M, Neuberger MS. Strategies for expressing human antibody repertoires in transgenic mice. IMMUNOLOGY TODAY 1996; 17:391-7. [PMID: 8783501 DOI: 10.1016/0167-5699(96)10025-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Repertoires of human antibodies can be created in transgenic mice carrying human immunoglobulin-gene loci in germline configuration. These 'transloci', introduced either as miniloci or as almost locus-sized regions, undergo rearrangement and hypermutation in mouse lymphoid tissue. Here, Marianne Brüggemann and Michael Neuberger review the use of such mice for raising antigen-specific human monoclonal antibodies, as well as their exploitation for studying regulatory aspects of antibody repertoire formation.
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Affiliation(s)
- M Brüggemann
- Dept of Development and Genetics, Babraham Institute, Cambridge, UK
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17
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McGuigan A, Huxley C. Replication of yeast DNA and novel chromosome formation in mouse cells. Nucleic Acids Res 1996; 24:2271-80. [PMID: 8710496 PMCID: PMC145922 DOI: 10.1093/nar/24.12.2271] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
To determine whether yeast DNA can replicate or segregate in mammalian cells, we have transferred genomic DNA from the yeast Saccharomyces cerevisiae into mouse cells. Most of the lines contained stably integrated yeast DNA. However, in two of the lines, the yeast DNA was maintained as numerous small extrachromosomal elements which were still present after 26 cell divisions in selection but which were lost rapidly out of selection. This indicates that, although yeast DNA can replicate in mouse cells, the yeast centromere does not function to give segregation. In one cell line we observed a large novel chromosome consisting almost entirely of yeast DNA. This chromosome segregates well and contains mouse centromeric minor satellite DNA and variable amounts of major satellite DNA which probably comprise the functional centromere. The yeast DNA in the novel chromosome has a compacted chromatin structure which may be responsible for the efficient formation of anaphase bridges. Furthermore, yeast DNA integrated into mouse chromosomes forms constrictions at the point of integration. These features have previously been presumed to be hallmarks of centromeric function in transfection assays aimed at identifying putative centromeric DNA. Hence our results suggest caution be exercised in the interpretation of such assays.
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Affiliation(s)
- A McGuigan
- Department of Biochemistry and Molecular Genetics, Imperial College School of Medicine at St Mary's, London, UK
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18
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Zou X, Xian J, Popov AV, Rosewell IR, Müller M, Brüggemann M. Subtle differences in antibody responses and hypermutation of lambda light chains in mice with a disrupted chi constant region. Eur J Immunol 1995; 25:2154-62. [PMID: 7664778 DOI: 10.1002/eji.1830250806] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Analysis of lambda light chain use in normal mice is made difficult by the dominant chi light chain repertoire. We produced mice rendered deficient in chi light chain expression by gene targeting and focused on questions concerned with the generation of lambda light chain diversity. Whilst these mice compensate the chi deficiency with increased lambda liters, and their Ig level is therefore not significantly reduced, they show major differences in immunization titers, germinal center (GC) development and somatic hypermutation. After immunization, using antigens that elicit a restricted IgL response in normal mice, we obtained in the chi-/- mice elevated primary antibody titers but a subsequent lack in titer increase after repeated antigen challenge. Analysis of the Peyer's patches (PP) revealed a dramatically reduced cell content with rather small but highly active GC. Flow cytometric analysis showed different cell populations in the PP with enriched peanut agglutinin (PNA)hi/CD45R(B220)+ B cells, implying that the apparent compensation for the lack of lambda light chain expression involves the GC microenvironment in cell selection, the initiation of hypermutation and high affinity expansion. The three V lambda genes, V1, V2 and Vx, are mutated in the GC B cells, but show no junctional diversity. In contrast, a reduced rate of V lambda hypermutation is found in the hybridoma antibodies, which appears to reflect a selection bias rather than structural constraints. However, mechanisms of somatic mutation and specificity selection can operate with equal efficiency on the few V lambda genes.
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Affiliation(s)
- X Zou
- Department of Development and Signalling, Babraham Institute, Cambridge, GB
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19
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Abstract
Yeast artificial chromosomes (YACs) have become essential research tools as they enable large fragments of DNA to be cloned. In order to overcome several disadvantages of YACs, including chimaerism and instability, several complementary bacterial artificial chromosome (BAC) vectors have been developed. More recently, attempts are being made to construct artificial chromosomes in mammalian cells (MACs).
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Affiliation(s)
- A P Monaco
- Imperial Cancer Research Fund Laboratories, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK
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20
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Davies NP, Rosewell IR, Richardson JC, Cook GP, Neuberger MS, Brownstein BH, Norris ML, Brüggemann M. Creation of mice expressing human antibody light chains by introduction of a yeast artificial chromosome containing the core region of the human immunoglobulin kappa locus. BIO/TECHNOLOGY (NATURE PUBLISHING COMPANY) 1993; 11:911-4. [PMID: 7763914 DOI: 10.1038/nbt0893-911] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have previously described a strategy for integrating selectable marker genes into yeast artificial chromosomes (YACs) to facilitate their transfer into embryonic stem (ES) cells. Here we apply this technology to create mice carrying the core region of the human immunoglobulin (Ig) kappa light chain locus. A YAC was isolated which contains a 300 kb insert spanning three V kappa segments, the J kappa cluster, the C kappa region and extending downstream of the Kde element. After modification of this YAC to integrate the selectable neo marker gene, the YAC was introduced into ES cells by protoplast fusion. Several ES cell clones were obtained which appeared to harbor one complete copy of the YAC while retaining little or no other yeast DNA. The ES cells were injected into blastocysts and the chimaeric mice were shown to rearrange the introduced human light chain genes with the resultant production of antibodies containing human kappa light chains in the serum.
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Affiliation(s)
- N P Davies
- Development and Differentiation Laboratory, AFRC Babraham Institute, Cambridge, U.K
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21
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Choi TK, Hollenbach PW, Pearson BE, Ueda RM, Weddell GN, Kurahara CG, Woodhouse CS, Kay RM, Loring JF. Transgenic mice containing a human heavy chain immunoglobulin gene fragment cloned in a yeast artificial chromosome. Nat Genet 1993; 4:117-23. [PMID: 8348148 DOI: 10.1038/ng0693-117] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have developed a method for the introduction of yeast artificial chromosomes (YACs) into transgenic mice. An 85 kilobase (kb) fragment of the human heavy chain immunoglobulin gene was cloned as a YAC, and embryonic stem cell lines carrying intact, integrated YACs were derived by co-lipofection of the YAC with an unlinked selectable marker. Chimaeric founder animals were produced by blastocyst injection, and offspring transgenic for the YAC were obtained. Analysis of serum from these offspring for human heavy chain antibody subunits demonstrated expression of the YAC-borne immunoglobulin gene fragment. Co-lipofection may prove to be a highly-successful means of producing transgenic mice containing large gene fragments in YACs.
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Affiliation(s)
- T K Choi
- GenPharm International, Mountain 94043
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22
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Jakobovits A, Moore AL, Green LL, Vergara GJ, Maynard-Currie CE, Austin HA, Klapholz S. Germ-line transmission and expression of a human-derived yeast artificial chromosome. Nature 1993; 362:255-8. [PMID: 8459850 DOI: 10.1038/362255a0] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Introduction of DNA fragments, hundreds of kilobases in size, into mouse embryonic stem (ES) cells would greatly advance the ability to manipulate the mouse genome. Mice generated from such modified cells would permit investigation of the function and expression of very large or crudely mapped genes. Large DNA molecules cloned into yeast artificial chromosomes (YACs) are stable and genetically manipulable within yeast, suggesting yeast-cell fusion as an ideal method for transferring large DNA segments into mammalian cells. Introduction of YACs into different cell types by this technique has been reported; however, the incorporation of yeast DNA along with the YAC has raised doubts as to whether ES cells, modified in this way, would be able to recolonize the mouse germ line. Here we provide, to our knowledge, the first demonstration of germ-line transmission and expression of a large human DNA fragment, introduced into ES cells by fusion with yeast spheroplasts. Proper development was not impaired by the cointegration of a large portion of the yeast genome with the YAC.
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Affiliation(s)
- A Jakobovits
- Cell Genesys Inc., Foster City, California 94404
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23
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Markie D, Ragoussis J, Senger G, Rowan A, Sansom D, Trowsdale J, Sheer D, Bodmer WF. New vector for transfer of yeast artificial chromosomes to mammalian cells. SOMATIC CELL AND MOLECULAR GENETICS 1993; 19:161-9. [PMID: 8511673 DOI: 10.1007/bf01233531] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A modification vector has been constructed to facilitate the transfer of yeast artificial chromosomes (YACs) to mammalian cells in culture by targeting a dominant selectable marker (G418 resistance) to the right arm of pYAC4 clones. The ADE2 gene is used for yeast selection with consequent disruption of the URA3 gene, allowing direct modification of YACs within the common host strain AB1380, and providing a simple test for correct targeting. This vector has been tested by modification of a 550-kb YAC containing part of the human MHC class II region and transfer to CHO cells by protoplast fusion. Analysis of 15 independent G418-resistant CHO lines obtained following fusion suggests the majority contain a complete YAC with moderate amplification in some lines.
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Affiliation(s)
- D Markie
- Cancer Genetics Laboratory, Imperial Cancer Research Fund, London, U.K
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24
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Davies NP, Brüggemann M. Extension of yeast artificial chromosomes by cosmid multimers. Nucleic Acids Res 1993; 21:767-8. [PMID: 8441698 PMCID: PMC309194 DOI: 10.1093/nar/21.3.767] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- N P Davies
- AFRC, Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, UK
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