Injecting Embryonic Stem Cells into Eight-Cell-Stage Mouse Embryos.

In this protocol, eight-cell-stage precompaction embryos from outbred mouse strains are used for the injection of hybrid or inbred embryonic stem (ES) cells. This process often leads to generation of fully ES cell-derived so-called F mice (VelociMice). Postinjection culture of embryos is necessary to achieve the highest ratio of fully ES cell-derived mice and high-degree chimeras.

Generation of fertile and fecund F0 XY female mice from XY ES cells.

Known examples of male to female sex reversal in mice are caused by either strain incompatibilities or mutations in genes required for male sex determination. The resultant XY females are often sterile or exhibit very poor fertility. We describe here embryonic stem (ES) cell growth conditions that promote the production of healthy, anatomically normal fertile and fecund female F0 generation mice completely derived from gene-targeted XY male ES cells.

Conditionals by inversion provide a universal method for the generation of conditional alleles.

Conditional mutagenesis is becoming a method of choice for studying gene function, but constructing conditional alleles is often laborious, limited by target gene structure, and at times, prone to incomplete conditional ablation. To address these issues, we developed a technology termed conditionals by inversion (COIN). Before activation, COINs contain an inverted module (COIN module) that lies inertly within the antisense strand of a resident gene.

Producing fully ES cell-derived mice from eight-cell stage embryo injections.

In conventional methods for the generation of genetically modified mice, gene-targeted embryonic stem (ES) cells are injected into blastocyst-stage embryos or are aggregated with morula-stage embryos, which are then transferred to the uterus of a surrogate mother. F0 generation mice born from the embryos are chimeras composed of genetic contributions from both the modified ES cells and the recipient embryos. Obtaining a mouse strain that carries the gene-targeted mutation requires breeding the chimeras to transmit the ES cell genetic component through the germ line to the next (F1) generation (germ line transmission, GLT).

VelociMouse: fully ES cell-derived F0-generation mice obtained from the injection of ES cells into eight-cell-stage embryos.

With the completion of the human and mouse genome sequences and the development of high-throughput knockout mouse technologies, there is now a need for equally high-throughput methods for the production of mice for phenotypic studies. In response to this challenge, we recently developed a new method termed VelociMouse for the production of F0-generation mice that are fully derived from gene-targeted ES cells. In the version of the VelociMouse method described here, laser ablation of a portion of the zona pellucid (zp) of a normal eight-cell-stage embryo facilitates ES cell injection.