Practice question

Original Yamanaka cocktail clearly demonstrated four transcription factors sufficient to convert mouse and human fibroblasts to embryonic stem-like state functionally and transcriptionally. Oct4 is pituitary octamer transcription factor essential for inner cell mass identity and epiblast maintenance, Sox2 partners directly with Oct4 on composite motifs, Klf4 Krüppel-like factor regulates proliferation while suppressing somatic gene expression, c-Myc oncogene enhances chromatin accessibility, glycolytic metabolism, and proliferation kinetics. Later refinements replaced c-Myc with L-Myc or omitted it entirely to reduce tumorigenicity, while Nanog and Lin28 serve as alternative supplements. Core OSKM remains gold standard for iPSC generation protocols universally.