White et al. 1 DEVELOPMENTAL ACTIVATION OF THE RB-E2F PATHWAY AND ESTABLISHMENT OF CELL CYCLE REGULATED CDK ACTIVITY DURING EMBRYONIC STEM CELL DIFFERENTIATION Josephine White * , Elaine Stead, Renate Faast * , Simon Conn * , Peter Cartwright * and Stephen Dalton *† * Department of Molecular Biosciences and Center for Molecular Genetics of Development, University of Adelaide, South Australia; † Department of Biochemistry and Molecular Biology and Department of Animal Sciences, Rhodes Center, University of Georgia, Athens, Georgia. †corresponding author; University of Georgia Rhodes Center 425 River Road Athens, Georgia 30602-2771 pH (706) 542 9857; FAX (706) 542 7925 Email sdalton@uga.edu Key words: cell division, development, R-point Running title: G1 control in ES cell differentiation Abbreviations: Cdk, cyclin-dependent kinase; EPL, early primitive ectoderm-like; ES, embryonic stem; EB, embryoid body; dpc, days post coitum; ChIP, chromatin immunoprecipitation