Dynamic changes in Sox2 spatio-temporal expression promote the second cell fate decision through / signaling in preimplantation mouse embryos.

Oct4 and Sox2 regulate the expression of target genes such as , and , by binding to their respective regulatory motifs. Their functional cooperation is reflected in their ability to heterodimerize on adjacent regulatory motifs, the composite Sox/Oct motif. Given that Oct4 and Sox2 regulate many developmental genes, a quantitative analysis of their synergistic action on different Sox/Oct motifs would yield valuable insights into the mechanisms of early embryonic development.