Viable offspring derived from fetal and adult mammalian cells

Abstract

Fertilization of mammalian eggs is followed by successive cell divisions and progressive differentiation, first into the early embryo and subsequently into all of the cell types that make up the adult animal. Transfer of a single nucleus at a specific stage of development, to an enucleated unfertilized egg, provided an opportunity to investigate whether cellular differentiation to that stage involved irreversible genetic modification. The first offspring to develop from a differentiated cell were born after nuclear transfer from an embryo-derived cell line that had been induced to become quiescent. Using the same procedure, we now report the birth of live lambs from three new cell populations established from adult mammary gland, fetus and embryo. The fact that a lamb was derived from an adult cell confirms that differentiation of that cell did not involve the irreversible modification of genetic material required for development to term. The birth of lambs from differentiated fetal and adult cells also reinforces previous speculation that by inducing donor cells to become quiescent it will be possible to obtain normal development from a wide variety of differentiated cells.

Towards an understanding of British public attitudes concerning human cloning

“…Warnock, 1984) but much of the more recent discussions have followed the cloning of Dolly the sheep (Wilmut et al, 1997), e.g. UK House of Commons Science and Technology Committee report (1997) and the consultation on Cloning Issues in Reproduction, Science and Medicine launched in 1998 by the Human Genetics Advisory Commission (HGAC) and the Human Fertilisation and Embryology Authority (HFEA) in the UK.…”

Reprogramming of genome function through epigenetic inheritance

“…The most pronounced manifestation of this erasure occurs when a differentiated somatic nucleus is transplanted back into an oocyte, which results in the restoration of totipotency [4][5][6][7] . The reconstituted egg can then progress forward to generate a new organism that is a genetic copy or a clone of the individual nuclear donor.…”

Use of strontium in the activation of bovine oocytes reconstructed by somatic cell nuclear transfer

“…An increased number of births of cloned animals using somatic cells has been reported in several species (Wilmut et al, 1997;Kato et al, 1998;Wakayama et al, 1998;Baguisi et al, 1999;Polejaeva et al, 2000), but the process of cloning is still inefficient. Birth rates were, in general, lower than 7% (Heyman et al, 2002), and many cloned offspring die just after birth or within few days or weeks of life (Hill et al, 1999;Heyman et al, 2002;Wilmut et al, 2002).…”

“…Cell lines cultured for three to nine passages were used in NT experiments. Serum starvation (DMEM + 0.5% FCS) was performed for 5-12 days before embryo reconstruction (Wilmut et al, 1997;Kato et al, 1998). Immunohistochemical staining was performed using monoclonal antibodies for detection of vimentin (Monoclonal Anti-Vimentin Clone V9) and cytokeratin (Monoclonal Anti-Pan Cytokeratin Clone C-11 FITC Conjugate) intermediate filaments for characterization of donor cells.…”