PDZ domain polarity complexes

a member of the group, said they used 58 embryos to generate three stem-cell populations, but two were lost at an early stage. But he said this was fewer embryos than was used by other groups and attributed the success to the use of donated embryos that had been screened for genetic disorders, rather than discarded embryos from in vitro fertilisation procedures which may not be of sufficient quality. The first human embryonic stem cell lines were created in 1998. There are just nine lines available across the world, the majority from Singapore, and they are extremely expensive. Scientists at King's College were granted one of the first two licences to produce human embryonic stem cells by the Human Fertilisation and Embryology Authority early last year. " Embryonic stem cells are the most useful ones because they are very primitive — they have the potential to develop into any type of cell in the body. We have to work out how to coax them to develop into specific types of cells, " says Minger. " We know that cell replacement therapy is effective in treating diseases such as diabetes and Parkinson's but it has been very difficult to produce enough cells to treat even one patient. An embryonic stem cell line would enable us to produce unlimited amounts. " Holy grail: Stem cells are the target of much research effort and offer promise in the research and treatment of many diseases and conditions. What are they? Three protein complexes, each containing at least one PDZ protein–protein interaction domain, are critical regulators of cell polarity in animals. Each complex can be referred to by one of its primary components: the Par-3 or Baz complex, including Par-6 and aPKC; the Crb complex, including Sdt; and the Scrib complex, including Dlg. The Lgl protein, which has activities similar to the Scrib complex, seems to physically associate not with the Scrib but with the Baz complex. Are they conserved across species? Yes: orthologous complexes are found in worms, flies and vertebrates. Not only is the composition of the complexes conserved, but there is also remarkable conservation of their localization, particularly in epithelial cells. Nevertheless, the mutant phenotypes caused by defects in components of the complexes vary across species, suggesting that the story may be more complicated. How were they identified? Primarily through genetic screens in model organisms. Mutations of Crb, Sdt and Baz cause …