Practice question

Shinya Yamanaka's landmark screen systematically tested 24 embryonic stem cell-associated transcription factors for ability to reactivate Fbx15 beta-geo and endogenous Oct4 promoter in mouse fibroblasts. Through iterative elimination of dispensable candidates, minimal cocktail Oct4, Sox2, Klf4, and c-Myc, termed OSKM, proved sufficient to induce pluripotent colonies contributing to chimeras and germline transmission. Overexpression via retroviral vectors triggered mesenchymal to epithelial transition, global DNA demethylation, and reactivation of endogenous pluripotency network, revolutionizing regenerative biology and earning Nobel recognition for cellular reprogramming concept.