Mass spectrometry for identification of proteins that specifically bind to a distal enhancer of the Oct4 gene

Transcription factor Oct4 is a marker of pluripotent stem cells and has a significant role in their self-renewal. Oct4 gene is controlled by three cis-regulatory elements – proximal promoter, proximal enhancer and distal enhancer. All of these elements are targets for binding of regulatory proteins. Distal enhancer is in our research focus because of its activity in early stages of embryonic development. There are two main sequences called site 2A and site 2B that are presented in distal enhancer. For this moment proteins which bind to a site 2A (CCCCTCCCCCC) remain unknown. Using combination of in vitro method electrophoretic mobility shift assay (EMSA) and mass spectromery we identified several candidates that can regulate Oct4 gene expression through site 2A. (paper)