Murine Mutagenesis Core

Producing mice models to support neuroscience research

NINDS Institutional Center Core Grant to Support Neuroscience Research: Murine Mutagenesis Core (MMC)


The mission of MMC is to effectively produce genetically engineered mice models using ES cell lines with a high probability of germline transmission or nuclease based technologies such as CRISPR. The MMC promotes interactions among a diverse group of neuroscientists at Johns Hopkins University. This has facilitated the completion of many studies that represent advances relevant to key issues in basic and clinical neuroscience, as illustrated in our List of Publications and List of Mutagenic Mice presenting work supported by the MMC. 

The MMC is funded by an NINDS Core Center Grant (P30 NS050274: “JHU Center for Neuroscience Research”). Services provided by this and the other two Cores funded by this grant, and also the Machine Shop, are available to three groups of investigators: (1) the thirteen Primary Center Investigators who are co-PIs of this P30 grant; (2) NINDS-funded investigators at The Johns Hopkins School of Medicine; and (3) on a case by case basis, other non-NINDS-funded neuroscience investigators at JHU. All applications for use of Core facilities are carefully evaluated by Core personnel and directors, and services are allocated based on availability and guidelines that govern this NINDS Core funding mechanism. 

Questions regarding eligibility to utilize Core Services can be addressed to the MMC Director (Xinzhong Dong, or the P30 Center Director (Alex Kolodkin, We can also provide expertise and resources for performing pilot experiments for a broad range of research.


The MMC is located in Room 915, Wood Basic Science Building, at 725 North Wolfe Street
Phone: 410-614-3858


A great deal of expertise is available to users of the Murine Mutagenesis Core. Director Xinzhong Dong has extensive experience in identifying steps in the process of ES cell targeting for new investigators, and in helping to develop protocols that allow for productive collaboration between the ES Cell Core and individual labs within the neuroscience community. 

In addition, consultant Bo Xiao has generated conditional knockout mice for several genes, and can assist in review of targeting construct design, the generation of targeting constructs, and in screening methods for homologous recombination and colony maintenance. Holly Wellington, Research Specialist, has extensive experience with the molecular and cell culture techniques which are critical to the core. Finally, Chip Hawkins, manager of the Johns Hopkins Transgenic Core Laboratory, is able to share his extensive experience in creating transgenic mice.


Services provided by the Core for a typical project include:

  • Providing guidance on the design of targeting construct;
  • Generating targeted ES cell lines for the production of chimeric mice;
  • Karyotyping ES cells to be micro-injected into blastocysts;
  • Cryopreservation of ES cell line and embryos;
  • Generating CRISPR sgRNA and Cas9 molecules;
  • Expanding and assisting with characterizing ES cell clones obtained from international repositories and consortia such as KOMP and EUCOMM.

Consultation is available from MMC directors and staff members on the entire procedures of generating gene knockout mice. Replace with: Consultation is also available on other genome engineering technologies such as BAC transgenics and integrase mediated knock-ins.


Prior to the initiation of a project, a brief meeting is generally required between the investigator and MMC facility staff resulting in a mutually acceptable research strategy. This strategy will outline specifics of the project including knockout strategy, KO construct design, screening assays, and other procedural issues relevant to the generation of targeted ES cells.

In addition, a completed Application for Service (Application for Service:ES Cells; Application for Service:KOMP cells; or Application for Service:Crispr), signed by the principal investigator, forwarded to Core Manager (Holly Wellington,, and approved by the Core Director, will also be required. The Core Director will prioritize the service requests according to the difficulty of the project and workload.

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