Successful somatic cell nuclear transfer (SCNT) has been reported across a range of species using a range of recipient cells including enucleated metaphase II (MII) arrested oocytes, enucleated activated MII oocytes, and mitotic zygotes. However, the frequency of development to term varies significantly, not only between different cytoplast recipients but also within what is thought to be a homogenous population of cytoplasts. One of the major differences between cytoplasts is the activities of the cell cycle regulated protein kinases, maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK). Dependent upon their activity, exposure of the donor nucleus to these kinases can have both positive and negative effects on subsequent development. Co-ordination of cell cycle stage of the donor nucleus with the activities of MPF and MAPK in the cytoplast is essential to avoid DNA damage and maintain correct ploidy. However, recent information suggests that these kinases may also effect reprogramming of the somatic nucleus and preimplantation embryo development by other mechanisms. This article will summarise the differences between cytoplast recipients, their effects on development and discuss the potential role/s of MPF and or MAPK in nuclear reprogramming.

INTRODUCTION
 MPF AND MAPK DURING OOCYTEMATURATION
 EFFECTS OF MPF AND MAPK ON DNADAMAGE AND REPLICATION IN DIFFERENTCYTOPLAST RECIPIENTS
 GENE EXPRESSION IN SCNT EMBRYOS
 MANIPULATION OF KINASE ACTIVITIES INOOCYTES
 EFFECTS ON GENE EXPRESSION
 DEVELOPMENT OF SCNT EMBRYOS
 CONCLUSION
 REFERENCES

• Inchul Choi(1Animal Development and Biotechnology Group, School of Biosciences, The University of Nottingham, Sutton Bonington Campus, Loughborough, 2Department of Animal Biosystem Sciences, College of Agriculture &Life Sciences, Chungnam National University)
• Keith H. S. Campbell(Animal Development and Biotechnology Group, School of Biosciences, The University of Nottingham,) Correspondence