Fbx15

Fbx15, otherwise known as Fbxo15, is a protein expressed in undifferentiated embryonic stem cells.

It is expressed during coexpression of Oct3/4 and SOX2, two genes identified to be important in embryonic stem cell self-renewal and differentiation repression. There is an enhancer site upstream of the Fbx15-encoding transcription gene that contains an octamer-like binding motif and a Sox-like binding motif.

Lacking of Fbx15 leads to normal embryonic development, but it is often used as a downstream identifier to check for stem cell pluripotency and also Oct3/4 activation, as Oct3/4 deactivation leads to a complete lack of Fbx15 expression.