Abstract
OCT4 is a crucial transcription factor in the pluripotent stem cell gene regulatory network and an essential factor for pluripotent reprogramming. We engineered the previously reported HEL24.3 hiPSC to generate an OCT4 reporter cell line by knocking-in a T2A nuclear EmGFP reporter cassette before the OCT4 gene STOP codon sequence. To enhance targeted insertion, homologous recombination was stimulated using targeted cutting at the OCT4 STOP codon with CRISPR/SpCas9. This HEL24.3-OCT4-nEmGFP cell line faithfully reports endogenous OCT4 expression, serving as a useful tool to examine temporal changes in OCT4 expression in live cells during hiPSC culture, differentiation and somatic cell reprogramming.