Transgenic Core Facility Services

  • Introduction
  • Animal Use
  • Fees and Electronic Ordering Portal
  • Sample Preparation
  • Services Offered
  • Custom Transgenic Mouse or Transgenic Rat Production
  • Bacterial Artificial Chromosome Engineering
  • Gene Targeting Service
  • ES Cell-Mouse Chimera Production
  • De Novo ES Cell Line Derivation
  • Personnel Training
  • Plasmids, ES Cells, and Culture Reagents
  • Material Transfer Agreements
  • Centralized Support
  • Conversion of Mouse Lines to Specific Pathogen Free Status
  • Embryo Cryopreservation/Recovery
  • Speed Cryo
  • In Vitro Fertilization
  • Sperm Cryo

  • Introduction
    The University of Michigan Transgenic Animal Model Core was established in 1989 in response to the need for transgenic technology by University Investigators. The mission of the Transgenic Core is to provide access to transgenic animal technology in an efficient, effective manner. This includes 1) the production of transgenic mice, 2) the production of transgenic rats and zinc finger nuclease gene knockout and knockin rats, 3) the production of gene-targeted mouse embryonic stem (ES) cells for mouse knockout models and in vitro studies, 4) the production of ES cell-mouse chimeras for mouse knockout models, 5) assisted reproduction technology for mice and rats, 6) de novo derivation of mouse ES cells from custom mice, and 7) hands-on training in mouse ES cell manipulation, pronuclear microinjection, and blastocyst injection. Researchers can use Transgenic Core laboratory space and resources side by side with staff members. Consultation in all phases of transgenic and gene targeting research from experimental design to mouse breeding is freely available. Meet the Staff.

    The Transgenic Core collaborates with the BAC Recombineering Core to prepare genetically modified bacterial artificial chromosomes (BACs). The mission of the BAC Core is to provide access to a complex technology to investigators at the so that they can use their resources to conduct research instead of developing tools for research. BACs are genetically modified by homologous recombination (BAC recombineering) to prepare DNA mutations, insertions and deletions. BACs can be used as transgenes to express reporter molecules (GFP), Cre recombinase, and mutant alleles in cell culture and mice. The BAC Core also prepares gene targeting vectors for the modification of chromosomes in ES cells.

    The Transgenic mouse core guarantees that at least three transgenic founder mice will be produced for each DNA construct. The overall average is ten founders. Since 1989 over 14,000 mouse transgenic founders were produced from more than 1,400 plasmid and BAC transgenes. Nearly 1000 transgenic rat founders have been produced, including BAC transgenic rat strains. Over 200 new mutant mouse models were produced by the electroporation of mouse ES cells with targeting vectors and another 60-odd strains were produced from ES cell clones obtained from the international mouse knock out project (KOMP). Some of these mouse and rat models have been published.

    University Committee on the Care and Use of Animals
    Prior to the production of genetically altered animals, investigators must have approval to use mice in their research from the University Committee on Use and Care of Animals.

    This facility exists to serve the needs of University of Michigan researchers. A list of fees is available. Investigators are invited to contact Thom Saunders with any questions. The genetically altered animals provided by this facility can only be used for research purposes. Access to cell lines and plasmids is contingent upon approved material transfer agreements. Request services by filling out a submission form at our electronic ordering portal .

    Sample Preparation
    For the production of conventional transgenic mice, investigators are responsible for providing a restriction digest containing 50 ug of the transgene insert. The Transgenic Core will purify DNA for microinjection as described. A minigel photo should accompany the digest, the DNA fragment to be purified should be clearly marked. Several things should be considered in designing a transgenic research project (see Transgenic Project Outline). Prokaryotic vector sequences interfere with the expression of some transgenes, thus unique restriction sites at the 5' and 3' ends of the construct should be available for vector removal. The transgene should contain unique markers so that its presence can be easily detected in DNA samples and its expression can be assayed and distinguished from endogenous gene expression.

    Certain transgenes may result in a very low yields of transgenic founders due to the intrinsic nature of the transgene. For example, certain genes will be deleterious or incompatible with proper growth and development of the embryo. Special arrangements should be made with the Core if the transgene is suspected to cause lethality. The expression of a transgene requires that the appropriate transcriptional control elements be included in the DNA construct. Expression is often influenced by the chromosomal site in which the transgene DNA is integrated. Preliminary studies in cell cultures are recommended to verify the integrity of the construct and the function of the promoter/enhancer. However, it is not always possible to predict in advance whether the transgene will be expressed in vivo. For these reasons, the Core cannot guarantee that transgenic founders will express the transgene.

    For the production of gene targeted mice with mutations induced by homologous recombination in ES cells, investigators are responsible for producing ES cell clones with targeted genetic mutations. The first step in gene targeting is to obtain a detailed restriction map of the genetic locus and knowledge of exon/intron boundaries. (see Gene Targeting Outline) Higher yields of targeted ES cell clones are obtained from isoegenic DNA, thus a clone(s) from a genomic library that exactly matches the ES cell line to be electroporated is strongly advised. Restriction mapping data is used to identify 5' and 3' arms for targeting vector construction and to establish a screening strategy for the identification of ES clones that have undergone homologous recombination. This requires the characterization of probes for Southern blot analysis that lie outside of targeting vector sequences. After the targeting vector has been cloned it is introduced into ES cells. Fastidious cell culture technique and specialized reagents are required to maintain ES cells in a pluripotent state. Differentiated ES cells will not produce chimeras with the ability to transmit targeted mutations through germ cells. Investigators are invited to contact Elizabeth Hughes for training in ES cell culture and to obtain reagents certified for ES cell culture. Due to the intrinsic variability of individual ES cell clones we can not guarantee that germline chimeras will be produced from any particular ES cell clone. The Transgenic Facilty tests and validates ES cell culture reagents to maximize the successful outcome of gene targeting projects.

    Services Offered: View Detailed Service List

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