Production of cloned mice and the mechanisms of reprogramming

Cloning mammals by nuclear transfer began over fifteen years ago, yet the basic biology underlying this process remains unclear. We have succeeded in generating cloned mice from adult/fetus somatic and cultured (e.g., ES, fibroblast, neural stem) cells. We also have succeeded to establish ES cell lines from somatic cell via nuclear transfer (NT-ES cell). As in other mammals, the overall efficiency of mouse cloning in all reports is less than 5%. Why is this efficiency so low? The concept of "nuclear reprogramming" links the efficiency of cloning to changes that an incoming nucleus must undergo to direct development, but its mechanisms are unknown. Nuclear transfer technique is a uniquely powerful research model to investigate the biology of mammalian cloning, including the mechanisms that underlie reprogramming. This is expected to provide insights that will allow us to increase cloning efficiency significantly.

History of Mammalian Cloning

Method of Nuclear Transfer     

Equipment of Micromanipulation (under construction)