be230cLecture6

The recipient egg is enucleated by ultraviolet

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Unformatted text preview: ear Reprogramming •  Robert Briggs and Thomas King, 1952, performed the first surgical nuclear transfer using a drawn glass pipege. Donor nuclei came from early embryos (blastula stage), and in their hands nuclei progressively lost the ability to direct development. Historical Origins of Nuclear Reprogramming In the late 1950’s (published 1962), John Gurdon performed the first nuclear transfer from adult Kssue. A single donor cell is sucked into a narrow micropipege (3) to break the plasma membrane, but not the nucleus. The recipient egg is enucleated by ultraviolet irradiaKon, the micropipege is injected into the egg and the donor nucleus is ejected from the micropipege (4). Some injected eggs form complete embryos (5), some of which develop into adult frogs (6). Some injected eggs form parKal embryos (7), cells from which can also be isolated, collected and have their nuclei transferred into enucleated eggs (8–10). This process is termed serial nuclear transfer and can also result in the formaKon of full embryos and live frogs (11,12). If a small piece of a parKal embryo (13) is labeled and transplanted into a host embryo (14), the resulKng tadpole (15) has parts derived from the graa. Here, a tail muscle has cells with a nucleus that originated from the intesKne of the original donor and cells from the host embryo. Experiments like this have shown that up to 30% of the original intesKnal epithelial cells have nuclei that can generate funcKonal muscle and nerve cells, highlighKng the high efficiency of nuclear reprogramming by eggs. Historical Origins of Nuclear Reprogramming •  Ian Wilmut and Keith Campbell, produced Dolly the Sheep by nuclear transfer. 3 4/18/13 Human TherapeuKc Cloning...
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This document was uploaded on 04/09/2014.

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