Epigenetic changes during nuclear reprogramming

Cibelli, J

Nuclear reprogramming or nuclear remodeling is the process by which a cell of a specific phenotype changes into a different one under the influence of foreign factors. These factors can be defined in the form of small molecules, DNA, RNA, miRNA or proteins. In the context of our presentation we will discuss nuclear reprogramming of a somatic cell into a pluripotent one. The most striking reprogramming events are those described during somatic cell nuclear transfer (SCNT). With the advent of induced pluripotent stem cells (iPSC) a similar ‘end product’ - i.e. embryonic stem cell-like cells - can be obtained by using only 3 transcription factors. As a consequence, the use of SCNT as a way of reprogramming differentiated cells has been deemed ‘obsolete’ however recent evidence has surfaced showing incomplete reprogramming in iPSCs, highlighting the need for more research in both areas. iPSC technology and SCNT rely on massive epigenetic changes. We will discuss their differences and similarities and point to aspects that remain to be addressed before both techniques are implemented as a standard tools in biomedicine. High-resolution analysis of overall genome methylation in iPSC and embryonic stem cells will be discussed as well as genetic and epigenetic changes observed in preimplantation embryos produced by SCNT.(AU)

Resumo apresentado no III International Symposium Animal Biology of Reproductive, São Pedro, SP, 22-24 out. 2010