We set out to develop an unbiased, genome-wide method to screen for proteins that locate to the OCT4 proximal enhancer (PE) in hESCs; for this purpose, we developed an optimized locus-specific proteomics approach in hESCs. First, we designed TALEN (Transcription Activator-Like Effector Nuclease) constructs to target the sequences that are near the OCT4 PE, located in a region of DNaseI hypersensitivity. TALEN constructs with the highest cutting efficiency were chosen for locus-specific proteomics. We then made modifications to the original TALEN protein to transform it into a catalytically-dead TALE (dTALE) protein that is optimized for locus-specific proteomics in hESCs via three steps: 1) The nuclease-domain FokI at the C-terminus was replaced by a GFP (green fluorescence protein); 2) a 3X FLAG tag at the N-terminus was included for following pull-down analysis; 3) the existing CMV promoter was replaced with an EF1alpha promoter that has robust expression in hESCs. This dTALE protein could then be chemically crosslinked to the OCT4 locus together with all the other proteins that bind to the locus. We verified that dTALE protein binds to the targeted locus by chromatin immunoprecipitation (ChIP)-qPCR. Following crosslinking, chromatin was sheared, and all the associated proteins were immunoprecipitated using an anti-FLAG antibody. Immunoprecipitation pulled down the dTALE protein as well as other proteins and complexes that are also attached to that region. Crosslinking was then reversed, and the samples were subjected to mass spectrometry to enable generation of a list of proteins that potentially bind to OCT4 PE locus.