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Bac to the future: The use of bac transgenic mice for neuroscience research

Nature Reviews Neuroscience volume 2, pages 861–870 (2001)Cite this article

Key Points

  • The development of methods for engineering bacterial artificial chromosomes (BACs), and for the efficient production of BAC transgenic mice, has allowed the design of new in vivo approaches to the analysis of gene expression and function in the brain.

  • The manipulation of BACs relies on three basic features. First, competence for homologous recombination is restored to the BAC host strain. Second, a shuttle vector with the desired reporter gene or modification cassette is used to target the modification cassette into a precise site on the genomic DNA insert. Third, unwanted vector sequences are resolved through a second homologous recombination event or excised using an appropriate site-specific recombinase.

  • The carrying capacity of BACs is several hundred kilobases. If larger fragments need to be manipulated, the use of yeast artificial chromosomes, which can carry fragments larger than 1 Mb, can be helpful.

  • The accurate transcription of BAC transgenes in vivo, coupled with the ability to easily insert, delete, or alter genes that reside in these large DNA constructs, has led to the development of new strategies in neuroscience research. The preparation of BAC transgenic mice can provide rapid access to the profile of cell types that express the gene of interest, to the localization of its encoded product within the cell, and to the phenotypic consequences of its overproduction. BACs can be used to introduce affinity tags for biochemical analyses of protein assemblies that are required for brain function, to map neuronal circuits that include the cell of interest, and to create cell-specific genetic perturbations.

  • The full potential of BACs has not yet been realized. It is feasible that, for example, they might be used in the near future to assist in the development of combinatorial transcription systems to target a given gene to single cell types, or in the implementation of systems that allow the transgenic silencing of neuronal activity.

Abstract

The development of methods for engineering bacterial artificial chromosomes (BACs), and for the efficient production of BAC transgenic mice, has allowed the design of in vivo approaches to the analysis of gene expression and function in the brain, which could not be accomplished using traditional methods. These strategies have shed light on the functions of single genes in the nervous system, and will accelerate the use of functional genomic approaches to neuroscience research.

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Figure 1: BAC manipulation by homologous recombination.
Figure 2: A modification cassette.
Figure 3: Visualization of brain lipid-binding protein expression in postnatal cerebellum.
Figure 4: Fluorescence-activated cell sorting of neurons from BAC transgenic mice.

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References

  1. Lander, E. S. et al. Initial sequencing and analysis of the human genome. Nature 409, 860–921 (2001).

    CAS  PubMed  Google Scholar 

  2. Venter, J. C. et al. The sequence of the human genome. Science 291, 1304–1351 (2001).

    CAS  PubMed  Google Scholar 

  3. Miklos, G. L. & Rubin, G. M. The role of the genome project in determining gene function: insights from model organisms. Cell 86, 521–529 (1996).A review of genetic and molecular approaches to gene function in invertebrates that provides insights into the increasing importance of transgenic organisms in understanding genes, pathways and biochemical functions in vivo.

    CAS  PubMed  Google Scholar 

  4. Giraldo, P. & Montoliu, L. Size matters: use of YACs, BACs and PACs in transgenic animals. Transgenic Res. 10, 83–103 (2001).A technical discussion of large DNA vectors and their use in producing transgenic mice.

    CAS  PubMed  Google Scholar 

  5. Yang, X. W., Model, P. & Heintz, N. Homologous recombination based modification in Escherichia coli and germline transmission in transgenic mice of a bacterial artificial chromosome. Nature Biotechnol. 15, 859–865 (1997).The first paper to describe the use of homologous recombination to manipulate BACs in E. coli . Provides the basic logic for manipulation of BACs and the first example of reporter gene expression from a modified BAC in transgenic mice.

    CAS  Google Scholar 

  6. Eggleston, A. K. & West, S. C. Exchanging partners: recombination in E. coli. Trends Genet. 12, 20–26 (1996).

    CAS  PubMed  Google Scholar 

  7. Zhang, Y., Buchholz, F., Muyrers, J. P. & Stewart, A. F. A new logic for DNA engineering using recombination in Escherichia coli. Nature Genet. 20, 123–128 (1998).

    CAS  PubMed  Google Scholar 

  8. Jessen, J. R. et al. Modification of bacterial artificial chromosomes through Chi-stimulated homologous recombination and its application in zebrafish transgenesis. Proc. Natl Acad. Sci. USA 95, 5121–5126 (1998).

    CAS  PubMed  PubMed Central  Google Scholar 

  9. Imam, A. M. et al. Modification of human β-globin locus PAC clones by homologous recombination in Escherichia coli. Nucleic Acids Res. 28, E65 (2000).

    CAS  PubMed  PubMed Central  Google Scholar 

  10. Lee, E. C. et al. A highly efficient Escherichia coli-based chromosome engineering system adapted for recombinogenic targeting and subcloning of BAC DNA. Genomics 73, 56–65 (2001).

    CAS  PubMed  Google Scholar 

  11. Messerle, M., Crnkovic, I., Hammerschmidt, W., Ziegler, H. & Koszinowski, U. H. Cloning and mutagenesis of a herpesvirus genome as an infectious bacterial artificial chromosome. Proc. Natl Acad. Sci. USA 94, 14759–14763 (1997).

    CAS  PubMed  PubMed Central  Google Scholar 

  12. Gong, S., Yang, X. W. & Heintz, N. Rapid modification of bacterial artificial chromosomes (BACs) for large-scale BAC-mediated transgenic studies (submitted for publication).

  13. Fabb, S. A. & Ragoussis, J. Yeast artificial chromosome vectors. Mol. Cell Biol. Hum. Dis. Ser. 5, 104–124 (1995).

    CAS  PubMed  Google Scholar 

  14. Ramón y Cajal, S. Histology of the Nervous System (English translation by N. Swanson and L. W. Swanson) (Oxford Univ. Press, New York, 1995).

    Google Scholar 

  15. Hunt, P. & Krumlauf, R. Hox codes and positional specification in vertebrate embryonic axes. Annu. Rev. Cell Biol. 8, 227–256 (1992).

    CAS  PubMed  Google Scholar 

  16. Wilkinson, D. G. Genetic control of segmentation in the vertebrate hindbrain. Perspect. Dev. Neurobiol. 3, 29–38 (1995).

    CAS  PubMed  Google Scholar 

  17. Lumsden, A. & Krumlauf, R. Patterning the vertebrate neuraxis. Science 274, 1109–1115 (1996).

    CAS  PubMed  Google Scholar 

  18. Rijli, F. M., Gavalas, A. & Chambon, P. Segmentation and specification in the branchial region of the head: the role of the Hox selector genes. Int. J. Dev. Biol. 42, 393–401 (1998).

    CAS  PubMed  Google Scholar 

  19. Trainor, P. A. & Krumlauf, R. Patterning the cranial neural crest: hindbrain segmentation and Hox gene plasticity. Nature Rev. Neurosci. 1, 116–124 (2000).

    CAS  Google Scholar 

  20. Buck, L. & Axel, R. A novel multigene family may encode odorant receptors: a molecular basis for odor recognition. Cell 65, 175–187 (1991).

    CAS  PubMed  Google Scholar 

  21. Zhao, H. et al. Functional expression of a mammalian odorant receptor. Science 279, 237–242 (1998).

    CAS  PubMed  Google Scholar 

  22. Fritze, C. E. & Anderson, T. R. Epitope tagging: general method for tracking recombinant proteins. Methods Enzymol. 327, 3–16 (2000).A review of the advantages and practical considerations for the use of epitope tags in vitro and in vivo.

    CAS  PubMed  Google Scholar 

  23. Martinez-Salas, E. Internal ribosome entry site biology and its use in expression vectors. Curr. Opin. Biotechnol. 10, 458–464 (1999).A practical discussion of IRES sequences, their discovery, and their use to create polycistronic mRNAs for expression in eukaryotes.

    CAS  PubMed  Google Scholar 

  24. Kuhar, S. G. et al. Changing patterns of gene expression define four stages of cerebellar granule neuron differentiation. Development 117, 97–104 (1993).

    CAS  PubMed  Google Scholar 

  25. Feng, L., Hatten, M. E. & Heintz, N. Brain lipid-binding protein (BLBP): a novel signaling system in the developing mammalian CNS. Neuron 12, 895–908 (1994).

    CAS  PubMed  Google Scholar 

  26. Schedl, A. et al. Transgenic mice generated by pronuclear injection of a yeast artificial chromosome. Nucleic Acids Res. 20, 3073–3077 (1992).

    CAS  PubMed  PubMed Central  Google Scholar 

  27. Schedl, A., Montoliu, L., Kelsey, G. & Schutz, G. A yeast artificial chromosome covering the tyrosinase gene confers copy number-dependent expression in transgenic mice. Nature 362, 258–261 (1993).An early study documenting correct expression from a large DNA transgene in mice. This study confirmed and extended earlier work from this laboratory, indicating that position-independent and copy-number-dependent expression could be achieved using a 250-kb YAC.

    CAS  PubMed  Google Scholar 

  28. Huxley, C. Exploring gene function: use of yeast artificial chromosome transgenesis. Methods 14, 199–210 (1998).

    CAS  PubMed  Google Scholar 

  29. Antoch, M. P. et al. Functional identification of the mouse circadian Clock gene by transgenic BAC rescue. Cell 89, 655–667 (1997).A companion paper to the positional cloning study, reporting the identification of the mouse Clock gene. It describes the use of gene dosage in BAC transgenic mice to show that Clock is rate limiting in vivo.

    CAS  PubMed  PubMed Central  Google Scholar 

  30. Wines, M. E., Shi, Y., Lindor, M. & Holdener, B. C. Physical localization of the mesoderm development (mesd) functional region. Genomics 68, 322–329 (2000).

    CAS  PubMed  Google Scholar 

  31. Mullins, L. J. et al. Granulation rescue and developmental marking of juxtaglomerular cells using 'piggy-BAC' recombination of the mouse Ren locus. J. Biol. Chem. 275, 40378–40384 (2000).

    CAS  PubMed  Google Scholar 

  32. Means, G. D., Boyd, Y., Willis, C. R. & Derry, J. M. Transgenic rescue of the tattered phenotype by using a BAC encoding Ebp. Mamm. Genome 12, 323–325 (2001).

    CAS  PubMed  Google Scholar 

  33. Probst, F. J. et al. Correction of deafness in shaker-2 mice by an unconventional myosin in a BAC transgene. Science 280, 1444–1447 (1998).

    CAS  PubMed  Google Scholar 

  34. Sabath, D. E., Spangler, E. A., Rubin, E. M. & Stamatoyannopoulos, G. Analysis of the human ζ-globin gene promoter in transgenic mice. Blood 82, 2899–2905 (1993).

    CAS  PubMed  Google Scholar 

  35. Callow, M. J., Stoltzfus, L. J., Lawn, R. M. & Rubin, E. M. Expression of human apolipoprotein B and assembly of lipoprotein(a) in transgenic mice. Proc. Natl Acad. Sci. USA 91, 2130–2134 (1994).

    CAS  PubMed  PubMed Central  Google Scholar 

  36. Frazer, K. A., Narla, G., Zhang, J. L. & Rubin, E. M. The apolipoprotein(a) gene is regulated by sex hormones and acute-phase inducers in YAC transgenic mice. Nature Genet. 9, 424–431 (1995).An interesting study showing the proper regulation of a human gene in YAC transgenic mice, even though this gene does not occur in the mouse genome. So, the regulatory code for transcription of this gene is present in lower vertebrates, even though the gene itself is not.

    CAS  PubMed  Google Scholar 

  37. Yang, X. W., Wynder, C., Doughty, M. L. & Heintz, N. BAC-mediated gene-dosage analysis reveals a role for Zipro1 (Ru49/Zfp38) in progenitor cell proliferation in cerebellum and skin. Nature Genet. 22, 327–335 (1999).The first deliberate use of gene-dosage analysis in transgenic mice to uncover a function for a gene that does not show an obvious phenotype in the null state.

    CAS  PubMed  Google Scholar 

  38. Zuo, J., Treadaway, J., Buckner, T. W. & Fritzsch, B. Visualization of α9 acetylcholine receptor expression in hair cells of transgenic mice containing a modified bacterial artificial chromosome. Proc. Natl Acad. Sci. USA 96, 14100–14105 (1999).

    CAS  PubMed  PubMed Central  Google Scholar 

  39. Yu, W. et al. Coordinate regulation of RAG1 and RAG2 by cell type-specific DNA elements 5′ of RAG2. Science 285, 1080–1084 (1999).

    CAS  PubMed  Google Scholar 

  40. DeFalco, J. et al. Virus-assisted mapping of neural inputs to a feeding center in the hypothalamus. Science 291, 2608–2613 (2001).An interesting new technique for neural tracing that combines BAC transgenic mice with genetically altered pseudorabies virus (PRV) expression to allow cell-specific and temporally controlled mapping of neural circuits.

    CAS  PubMed  Google Scholar 

  41. Carvajal, J. J., Cox, D., Summerbell, D. & Rigby, P. W. A BAC transgenic analysis of the Mrf4/Myf5 locus reveals interdigitated elements that control activation and maintenance of gene expression during muscle development. Development 128, 1857–1868 (2001).

    CAS  PubMed  Google Scholar 

  42. John, R. M. et al. Imprinted expression of neuronatin from modified BAC transgenes reveals regulation by distinct and distant enhancers. Dev. Biol. 236, 387–399 (2001).

    CAS  PubMed  Google Scholar 

  43. Sabatini, B. L. & Svoboda, K. Analysis of calcium channels in single spines using optical fluctuation analysis. Nature 408, 589–593 (2000).

    CAS  PubMed  Google Scholar 

  44. Steward, O. mRNA localization in neurons: a multipurpose mechanism? Neuron 18, 9–12 (1997).

    CAS  PubMed  Google Scholar 

  45. Martin, K. C., Barad, M. & Kandel, E. R. Local protein synthesis and its role in synapse-specific plasticity. Curr. Opin. Neurobiol. 10, 587–592 (2000).

    CAS  PubMed  Google Scholar 

  46. Steward, O. & Schuman, E. M. Protein synthesis at synaptic sites on dendrites. Annu. Rev. Neurosci. 24, 299–325 (2001).

    CAS  PubMed  Google Scholar 

  47. Lin, R. C. & Scheller, R. H. Mechanisms of synaptic vesicle exocytosis. Annu. Rev. Cell Dev. Biol. 16, 19–49 (2000).

    CAS  PubMed  Google Scholar 

  48. Sudhof, T. C. The synaptic vesicle cycle revisited. Neuron 28, 317–320 (2000).

    CAS  PubMed  Google Scholar 

  49. Sollner, T. H. & Rothman, J. E. Molecular machinery mediating vesicle budding, docking and fusion. Experientia 52, 1021–1025 (1996).

    CAS  PubMed  Google Scholar 

  50. Cohen, R. S., Blomberg, F., Berzins, K. & Siekevitz, P. The structure of postsynaptic densities isolated from dog cerebral cortex. I. Overall morphology and protein composition. J. Cell Biol. 74, 181–203 (1977).

    CAS  PubMed  PubMed Central  Google Scholar 

  51. Blomberg, F., Cohen, R. S. & Siekevitz, P. The structure of postsynaptic densities isolated from dog cerebral cortex. II. Characterization and arrangement of some of the major proteins within the structure. J. Cell Biol. 74, 204–225 (1977).

    CAS  PubMed  PubMed Central  Google Scholar 

  52. Kennedy, M. B. Signal-processing machines at the postsynaptic density. Science 290, 750–754 (2000).

    CAS  PubMed  Google Scholar 

  53. Green, D. R. & Reed, J. C. Mitochondria and apoptosis. Science 281, 1309–1312 (1998).

    CAS  PubMed  Google Scholar 

  54. Arnold, D., Feng, L., Kim, J. & Heintz, N. A strategy for the analysis of gene expression during neural development. Proc. Natl Acad. Sci. USA 91, 9970–9974 (1994).

    CAS  PubMed  PubMed Central  Google Scholar 

  55. Arnold, D. B. & Clapham, D. E. Molecular determinants for subcellular localization of PSD-95 with an interacting K+ channel. Neuron 23, 149–157 (1999).

    CAS  PubMed  Google Scholar 

  56. Fields, S. & Song, O. A novel genetic system to detect protein–protein interactions. Nature 340, 245–246 (1989).

    CAS  PubMed  Google Scholar 

  57. Fondell, J. D., Ge, H. & Roeder, R. G. Ligand induction of a transcriptionally active thyroid hormone receptor coactivator complex. Proc. Natl Acad. Sci. USA 93, 8329–8333 (1996).

    CAS  PubMed  PubMed Central  Google Scholar 

  58. Rout, M. P. et al. The yeast nuclear pore complex: composition, architecture, and transport mechanism. J. Cell Biol. 148, 635–651 (2000).

    CAS  PubMed  PubMed Central  Google Scholar 

  59. Levine, K., Tinkelenberg, A. H. & Cross, F. The CLN gene family: central regulators of cell cycle Start in budding yeast. Prog. Cell Cycle Res. 1, 101–114 (1995).

    CAS  PubMed  Google Scholar 

  60. Rorth, P. A modular misexpression screen in Drosophila detecting tissue-specific phenotypes. Proc. Natl Acad. Sci. USA 93, 12418–12422 (1996).

    CAS  PubMed  PubMed Central  Google Scholar 

  61. Perrimon, N. New advances in Drosophila provide opportunities to study gene functions. Proc. Natl Acad. Sci. USA 95, 9716–9717 (1998).

    CAS  PubMed  PubMed Central  Google Scholar 

  62. Smith, D. J. et al. Functional screening of 2 Mb of human chromosome 21q22.2 in transgenic mice implicates minibrain in learning defects associated with Down syndrome. Nature Genet. 16, 28–36 (1997).

    CAS  PubMed  Google Scholar 

  63. King, D. P. et al. Positional cloning of the mouse circadian Clock gene. Cell 89, 641–653 (1997).

    CAS  PubMed  PubMed Central  Google Scholar 

  64. Roberts, P. A. & Broderic, D. J. Properties and evolutionary potential of newly induced tandem duplications in Drosophila melanogaster. Genetics 102, 75–89 (1982).

    CAS  PubMed  PubMed Central  Google Scholar 

  65. Jansen, G. et al. The complete family of genes encoding G proteins of Caenorhabditis elegans. Nature Genet. 21, 414–419 (1999).

    CAS  PubMed  Google Scholar 

  66. Heintz, N. & Zoghbi, H. Y. Insights from mouse models into the molecular basis of neurodegeneration. Annu. Rev. Physiol. 62, 779–802 (2000).

    CAS  PubMed  Google Scholar 

  67. Zoghbi, H. Y. & Orr, H. T. Glutamine repeats and neurodegeneration. Annu. Rev. Neurosci. 23, 217–247 (2000).

    CAS  PubMed  Google Scholar 

  68. Orr, H. T. Beyond the Qs in the polyglutamine diseases. Genes Dev. 15, 925–932 (2001).

    CAS  PubMed  Google Scholar 

  69. Wheeler, V. C. et al. Length-dependent gametic CAG repeat instability in the Huntington's disease knock-in mouse. Hum. Mol. Genet. 8, 115–122 (1999).

    CAS  PubMed  Google Scholar 

  70. Hodgson, J. G. et al. A YAC mouse model for Huntington's disease with full-length mutant huntingtin, cytoplasmic toxicity, and selective striatal neurodegeneration. Neuron 23, 181–192 (1999).

    CAS  PubMed  Google Scholar 

  71. Lamb, B. T. et al. Amyloid production and deposition in mutant amyloid precursor protein and presenilin-1 yeast artificial chromosome transgenic mice. Nature Neurosci. 2, 695–697 (1999).

    CAS  PubMed  Google Scholar 

  72. Gu, H., Marth, J. D., Orban, P. C., Mossmann, H. & Rajewsky, K. Deletion of a DNA polymerase β gene segment in T cells using cell type-specific gene targeting. Science 265, 103–106 (1994).

    CAS  PubMed  Google Scholar 

  73. Mansuy, I. M. & Bujard, H. Tetracycline-regulated gene expression in the brain. Curr. Opin. Neurobiol. 10, 593–596 (2000).

    CAS  PubMed  Google Scholar 

  74. Dulac, C. Cloning of genes from single neurons. Curr. Top. Dev. Biol. 36, 245–258 (1998).

    CAS  PubMed  Google Scholar 

  75. Emmert-Buck, M. R. et al. Laser capture microdissection. Science 274, 998–1001 (1996).

    CAS  PubMed  Google Scholar 

  76. Tomomura, M., Rice, D. S., Morgan, J. I. & Yuzaki, M. Purification of Purkinje cells by fluorescence-activated cell sorting from transgenic mice that express green fluorescent protein. Eur. J. Neurosci. 14, 57–63 (2001).

    CAS  PubMed  Google Scholar 

  77. Mombaerts, P. et al. Visualizing an olfactory sensory map. Cell 87, 675–686 (1996).

    CAS  PubMed  Google Scholar 

  78. Bozza, T. C. & Mombaerts, P. Olfactory coding: revealing intrinsic representations of odors. Curr. Biol. 11, R687–R690 (2001).

    CAS  PubMed  Google Scholar 

  79. DePrimo, S. E., Stambrook, P. J. & Stringer, J. R. Human placental alkaline phosphatase as a histochemical marker of gene expression in transgenic mice. Transgenic Res. 5, 459–466 (1996).

    CAS  PubMed  Google Scholar 

  80. Leighton, P. A. et al. Defining brain wiring patterns and mechanisms through gene trapping in mice. Nature 410, 174–179 (2001).

    CAS  PubMed  Google Scholar 

  81. Yoshihara, Y. et al. A genetic approach to visualization of multisynaptic neural pathways using plant lectin transgene. Neuron 22, 33–41 (1999).Shows the use of transgenic expression of wheat-germ agglutinin to trace neuronal circuits in transgenic mice.

    CAS  PubMed  Google Scholar 

  82. Horowitz, L. F., Montmayeur, J. P., Echelard, Y. & Buck, L. B. A genetic approach to trace neural circuits. Proc. Natl Acad. Sci. USA 96, 3194–3199 (1999).

    CAS  PubMed  PubMed Central  Google Scholar 

  83. Johns, D. C., Marx, R., Mains, R. E., O'Rourke, B. & Marban, E. Inducible genetic suppression of neuronal excitability. J. Neurosci. 19, 1691–1697 (1999).

    CAS  PubMed  PubMed Central  Google Scholar 

  84. Nadeau, H., McKinney, S., Anderson, D. J. & Lester, H. A. ROMK1 (Kir1.1) causes apoptosis and chronic silencing of hippocampal neurons. J. Neurophysiol. 84, 1062–1075 (2000).

    CAS  PubMed  Google Scholar 

  85. White, B. H. et al. Targeted attenuation of electrical activity in Drosophila using a genetically modified K+ channel. Neuron 31, 699–711 (2001).

    CAS  PubMed  Google Scholar 

  86. Coulson, A., Waterston, R., Kiff, J., Sulston, J. & Kohara, Y. Genome linking with yeast artificial chromosomes. Nature 335, 184–186 (1988).

    CAS  PubMed  Google Scholar 

  87. Shizuya, H. et al. Cloning and stable maintenance of 300-kilobase-pair fragments of human DNA in Escherichia coli using an F-factor-based vector. Proc. Natl Acad. Sci. USA 89, 8794–8797 (1992).

    CAS  PubMed  PubMed Central  Google Scholar 

  88. Ioannou, P. A. et al. A new bacteriophage P1-derived vector for the propagation of large human DNA fragments. Nature Genet. 6, 84–89 (1994).

    CAS  PubMed  Google Scholar 

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Acknowledgements

I thank J. Friedman, M. E. Hatten, R. B. Darnell and X. W. Yang for their helpful comments during the preparation of this article. I also thank S. M. Magdaleno and T. Curran for the phrase “BAC to the future”, which first appeared in a commentary on gene dosage in mice, published in Nature Genetics.

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Authors and Affiliations

  1. Howard Hughes Medical Institute, Laboratory of Molecular Biology, The Rockefeller University, New York, 10021, USA

    Nathaniel Heintz

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DATABASES

FlyBase

Shaker

LocusLink

Acra9

BLBP

calbindin

Clock

huntingtin

minibrain

Mrf4

Myf5

Nnat

Npy

presenilin 1

protein A

Rag1

Rag2

Ren1

Tau

Zipro1

OMIM

Alzheimer's disease

Down's syndrome

Huntington's disease

spinocerebellar ataxia 1

FURTHER INFORMATION

knockout and knock-in animals

transgenic animals

yeast artificial chromosomes

Glossary

EXPRESSED SEQUENCE TAGS

Short (200–500 base pairs) DNA sequences that represent the sequences expressed in an organism under a given condition. They are generated from the 3′- and 5′-ends of randomly selected complementary DNA clones. The purpose of EST sequencing is to scan for all the protein-coding genes, and to provide a tag for each gene on the genome.

REPORTER GENE

A gene that encodes an easily assayed product. It is coupled to the upstream sequence of another gene, and can then be transfected into cells to identify factors that activate response elements in the upstream region of the gene of interest.

EPISOME

A genetic unit of replication that can exist either extrachromosomally or integrated into the bacterial chromosome.

HOMOLOGOUS RECOMBINATION

The substitution of a segment of DNA with one that is identical or almost identical to it. It occurs naturally during meiosis, but can also be used experimentally for gene targeting to modify the sequence of a gene.

RECOMBINASE

An enzyme that recognizes specific DNA sequences and catalyses the reciprocal exchange of DNA strands between these sites during viral integration, chromosomal segregation and related processes.

DOMINANT ACTIVATING

Describes a mutant molecule that is capable of forming a heteromeric complex with the normal molecule, generating a constitutively active protein.

DOMINANT NEGATIVE

Describes a mutant molecule that is capable of forming a heteromeric complex with the normal molecule, knocking out the activity of the entire complex.

INTERNAL RIBOSOME ENTRY SITE

A sequence that is inserted between the coding regions of two proteins, and allows efficient assembly of the ribosome complex in the middle of a transcript, leading to translation of the second protein.

HOX GENES

Transcription factors expressed in specific patterns that are important for determining regional identity along the anteroposterior axis of the embryo. They are also known as homeobox genes.

RHOMBOMERES

Neuroepithelial segments found in the embryonic hindbrain that adopt distinct molecular and cellular properties, restrictions in cell mixing, and ordered domains of gene expression.

EPITOPE TAG

The immunological determinant of an antigen, which has been fused to a protein of interest for its subsequent localization with specific antibodies.

POLYCISTRONIC MESSENGER RNA

A messenger RNA that codes for more than one protein.

CRE RECOMBINASE SYSTEM

A method in which the Cre enzyme catalyses recombination between loxP sequences. If the loxP sequences are arranged as a direct repeat, recombination will delete the DNA between the sites.

FLP RECOMBINASE

A protein involved in the amplification of the yeast 2-μm plasmid. It encodes a protein that catalyses site-specific recombination between sites called Flp recognition targets (FRT). The Flp/FRT system has been successfully applied as a site-specific recombination system.

TETRACYCLINE-DEPENDENT TRANSACTIVATOR SYSTEM

A system that allows the precise control of gene expression in eukaryotic systems through the administration of tetracycline. It is based on two key elements: the tetracycline-dependent transactivator protein (tTA) and the target gene under the control of a tTA-responsive element. When these elements are transfected into eukaryotic cells, the tTA binds to the tTA-responsive element to initiate transcription. Tetracycline can then be administered to stop expression of the target gene.

REVERSE TETRACYCLINE-DEPENDENT TRANSACTIVATOR SYSTEM

A system that allows the precise control of gene expression in eukaryotic systems through the administration of tetracycline. It is based on two key elements: a mutant form of the tetracycline-dependent transactivator protein (tTA), and the target gene under the control of a tTA-responsive element. Once these key elements have been transfected into eukaryotic cells, the mutant tTA is expressed, but does not bind the tTA-responsive element. Binding of the mutant tTA to the tTA-responsive element and initiation of transcription is then induced by the addition of tetracycline.

POSTSYNAPTIC DENSITY

An electron-dense thickening underneath the postsynaptic membrane at excitatory synapses that contains receptors, structural proteins linked to the actin cytoskeleton and signalling machinery, such as protein kinases and phosphatases.

YEAST INTERACTION SCREEN

A system used to determine the existence of direct interactions between proteins. It commonly involves the use of plasmids that encode two hybrid proteins: one that is fused to the GAL4 DNA-binding domain, and one that is fused to the GAL4 activation domain. The two proteins are expressed together in yeast; if they interact, the resulting complex will drive the expression of a reporter gene, commonly β-galactosidase.

MASS SPECTROMETRY

In mass spectrometry, a substance is bombarded with an electron beam of sufficient energy to fragment the molecule. The cations that are produced are accelerated in a vacuum through a magnetic field, and sorted on the basis of mass-to-charge ratio. The ratio is roughly equivalent to the molecular weight of the fragment.

POSITIONAL CLONING

A strategy for cloning on the basis of location in the genome, rather than the function of the product. It commonly involves linking the locus of interest to one that has already been mapped.

SUPPRESSION SCREEN

A system used to identify genes that, when overexpressed, lead to the suppression of a mutant phenotype. By contrast, an overexpression screen is used to identify genes that, when overexpressed, lead to the appearance of a mutant phenotype, and a misexpression screen is used to identify genes that, when expressed in ectopic regions, lead to the appearance of a mutant phenotype.

P ELEMENT

A Drosophila transposable element that has been used as a tool for insertion mutagenesis and for germ-line transformation.

HEAT-SHOCK PROMOTERS

DNA sequences that control the expression of a family of proteins (heat-shock proteins) that are synthesized in response to increases in temperature.

GAL4 UAS SYSTEM

An expression system in which ectopically expressed GAL4 will activate the transcription of a reporter gene or another target gene that is downstream of an upstream activation sequence (UAS).

POLYGLUTAMINE DISORDERS

Diseases characterized at the molecular level by CAG-trinucleotide-repeat expansions in a gene, which translate into an excess of glutamine repeats in the coded protein. A well-known example is Huntington's disease, which is caused by the presence of additional CAG repeats in the gene huntingtin.

KNOCK-IN TRANSGENESIS

The insertion of a mutant gene at the exact site of the genome where the corresponding wild-type gene is located. This approach is used to ensure that the effect of the mutant gene is not affected by the activity of the endogenous locus.

FLUORESCENCE-ACTIVATED CELL SORTING

A method that allows the separation of cells that express a specific protein by tagging them with a fluorescent antibody against the molecule of interest. A laser beam excites the fluorescent tag, and the emission of light triggers the cell sorting.

GENE TRAPPING

A mutation strategy that uses insertion vectors to trap or isolate transcripts from flanking genes. The inserted sequence acts as a tag from which to clone the mutated gene.

LECTINS

Sugar-binding proteins that tend to agglutinate cells. Concanavalin A is a widely used example.

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Heintz, N. Bac to the future: The use of bac transgenic mice for neuroscience research . Nat Rev Neurosci 2, 861–870 (2001). https://doi.org/10.1038/35104049

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