Keith Henry Stockman Campbell

Quiescent cell populations for nuclear transfer

A method of reconstituting an animal embryo involves transferring the nucleus from a quiescent donor cell into a suitable recipient cell. The donor cell is quiescent, in that it is caused to exit from the growth and division cycle at G1 and to arrest in the G0 state. Nuclear transfer may take place by cell fusion. The reconstituted embryo may then give rise to one or more animals. The invention is useful in the production of transgenic animals as well as non-transgenics of high genetic merit.

Unactivated oocytes as cytoplast recipients for nuclear transfer

A method of reconstituting an animal embryo involves transferring a diploid nucleus into an oocyte which is arrested in the metaphase of the second meiotic division. The oocyte is not activated at the time of transfer, so that the donor nucleus is kept exposed to the recipient cytoplasm for a period of time. The diploid nucleus can be donated by a cell in either the G0 or G1 phase of the cell cycle at the time of transfer. Subsequently, the reconstituted embryo is activated. Correct ploidy is maintained during activation, for example, by incubating the reconstituted embryo in the presence of a microtubule inhibitor such as nocodazole. The reconstituted embryo may then give rise to one or more live animal births. The invention is useful in the production of transgenic animals as well as non-transgenics of high genetic merit.

Totipotency or multipotentiality of cultured cells: Applications and progress

Abstract The stable introduction of new genetic material into breeding programmes for farm animal species requires germ line modification. One route by which to achieve this is by the combination of embryo manipulation and molecular biological techniques. In the mouse, genetic manipulation of embryonic stem (ES) cells in culture followed by the production of chimeric animals by blastocyst injection has proved a powerful tool for germ line manipulation. In contrast, the absence of proven ES lines in farm animal species has restricted similar progress, the production of transgenic animals being limited to gene addition using the technique of pronuclear injection. An alternative and desirable route to germ line modification in farm animals is to produce offspring by nuclear transfer from a cell line which can be maintained in culture. In sheep this has now been achieved with the birth of live lambs from an embryo derived, epithelial like cell line. The combination of this technology with that developed in ES cells for genetic modification will herald a new era in the germ line modification of farm animal species.