Induced pluripotent stem cells (iPS cells) are pluripotent cells made from adult body cells. iPS cells can be produced from adult somatic cells using appropriate protein transcription factors.A specialised cell, such as a skin cell, still contains all of the genes, but the genes needed for pluripotency have been switched off. To reprogramme it:1. Genes for several transcription factors associated with pluripotency are introduced into the cell, usually using a harmless virus as a vector.
2. The genes are expressed, so the transcription factors are made.
3. The transcription factors switch on the genes associated with pluripotency, and the cell returns to an unspecialised, pluripotent state.
iPS cells behave very much like embryonic stem cells: they can divide in unlimited numbers and can be stimulated to differentiate into almost any type of cell.Advantages
• They can be made from the patient's own cells, so tissue grown from them is genetically identical to the patient and should not be rejected by the immune system.
• No embryo is destroyed, which avoids many of the ethical objections to using embryonic stem cells.
• Adult cells are easy to obtain.Disadvantages
• They are not identical to embryonic stem cells, and some genes may not be fully reprogrammed.
• One of the transcription factor genes used is linked to cancer, and the viral vector could disrupt other genes, so there is a risk of tumours.
• The process is slow and has a low success rate.
2. The genes are expressed, so the transcription factors are made.
3. The transcription factors switch on the genes associated with pluripotency, and the cell returns to an unspecialised, pluripotent state.
iPS cells behave very much like embryonic stem cells: they can divide in unlimited numbers and can be stimulated to differentiate into almost any type of cell.Advantages• They can be made from the patient's own cells, so tissue grown from them is genetically identical to the patient and should not be rejected by the immune system.
• No embryo is destroyed, which avoids many of the ethical objections to using embryonic stem cells.
• Adult cells are easy to obtain.Disadvantages
• They are not identical to embryonic stem cells, and some genes may not be fully reprogrammed.
• One of the transcription factor genes used is linked to cancer, and the viral vector could disrupt other genes, so there is a risk of tumours.
• The process is slow and has a low success rate.