The Genome Modification Facility (GMF) provides transgenic, gene targeting, and other services to investigators of Harvard University and its affiliated institutions, as well as to investigators within the US and abroad. The GMF performs microinjections of DNA into fertilized embryos to generate transgenic mice, DNA transfection into ES cells for the creation of recombinant ES cell clones, injection of gene-targeted ES cells into host blastocysts to generate gene knock-out or knock-in mice, teratoma formation studies, and other related ES cell-based services. The GMF also generates preps for gRNA ex-vivo validations, and performs microinjections of TALENs or CRISPR/Cas9 and sgRNA as well as DNA donors into mouse zygotes for gene editing projects. Other services include cryopreservation of mouse sperm and embryos, in vitro fertilization, recovery of cryopreserved mouse sperm and embryos, rederivation of pathogen free mouse lines, and establish new ES cell lines from wild type and mutant mice with a variety of genetic backgrounds. Our staff provides general consultations on experimental designs and vectors for gene modification-related projects, DNA preparation, recombinant ES clones, mouse genotyping, colony breeding and husbandry. We can also customize services as requested to support development of animal models of human diseases.  To contact us, please send an email to


ES Cell Gene Targeting

  • Gene targeting in ES cells: C57BL/6-129 Hybrid, C57BL/6N (JM8A), C57BL/6, or 129 ES Cells transfection package (from DNA transfection to ES cell pellets in 96-well plates) ~200 colonies
  • Expansion of ES Clones (each clone, per 9.6 cm2 growing area)
  • ES cells Mycoplasma screening
  • ES cells karyotyping

ES or iPS Cell Line Services

  • Validation of human or mouse iPS cells by teratoma formation
  • Establish new ES Cell lines from mouse embryos (mutants or wild types)
  • Characterization of the pluripotent status of mES by immunocytochemistry analysis (AP, or Sox-2, Oct-4, SSEA-1)
  • Examination of the pluripotent status of mES  and germ line transmission by microinjection

Microinjection of ES or iPS Cells, DNA, TALEN, or CRISPR

  • Microinjection of ES clones (targeted 129, JM8A, or hybrid ES Cells) into embryos of C57BL/6, B6-albino, hybrid, or CD1 for generating gene targeted mice
  • Microinjection of iPS clones into embryos of C57BL/6, B6-albino, hybrid, or CD1
  • Microinjection of  plasmid DNA into pronuclei of embryos: hybrid mouse strain, C57BL/6, FVB, Balb/C, or mutant strains for generating transgenic mice
  • Microinjection of  BAC or YAC DNA into pronuclei of embryos:  hybrid mouse strain, or C57BL/6
  • Microinjection of TALENs or CRISPR reagents into mouse zygotes for gene knock out projects
  • Microinjection of TALENs or CRISPR reagents and DNA donors into mouse zygotes for gene knockin projects
  • gRNA ex-vivo validation preps generation for testing gRNAs and selecting the best gRNA for an injection project

Cryopreservation, IVF, & Strain Rederivation

  • Sperm Cryopreservation - including cryo-sperm quality test
  • Recovery of live pups following sperm cryopreservation and cryo-sperm test
  • IVF recovery of mice from cryopreserved sperm (one litter of pups provided)
  • IVF recovery of mice from fresh sperm for rapid expansion of mouse colony
  • Embryo Cryopreservation
  • Resuscitation of cryopreserved mouse embryos
  • Rederivation of mouse strains by embryo transfer to generate pathogen free mouse lines

Additional Services

  • DNA purification for microinjection or gene targeting
  • DNA extraction from ES clones
  • Mouse colony breeding
  • Mouse ID tag & tail biopsy
  • Mouse tail DNA extraction
  • Provide mouse embryonic fibroblast (EF) cells
  • Provide mouse embryos
  • Provide CD1-Lactating mouse with litter
  • Consultation: services include discussion of issues concerning CRISPR reagents, project preparation, transgenes, targeting constructs, ES cell lines, selection and mouse colony breeding strategies, cryopreservation and rederivation strategies and preparations