KLF4 N-terminal variance modulates induced reprogramming to pluripotency

Abstract

As the quinteßential reprogramming model, OCT3/4, SOX2, KLF4, and c-MYC re-wire somatic cells to achieve induced pluripotency. Yet, subtle differences in methodology confound comparative studies of reprogramming mechanisms. Employing transposons, we systematically aßeßed cellular andmolecular hallmarks ofmouse somatic cell reprogramming by various polycistronic caßettes. Reprogramming responses varied in the extent of initiation and stabilization of transgene-independent pluripotency. Notably, the caßettes employed one of two KLF4 variants, differing only by nine N-terminal amino acids, which generated dißimilar protein stoichiometry. Extending the shorter variant by nine N-terminal amino acids or augmenting stoichiometry by KLF4 supplementation rescued both protein levels and phenotypic disparities, implicating a threshold in determining reprogramming outcomes. Strikingly, global gene expreßion patterns elicited by published polycistronic caßettes diverged according to each KLF4 variant. Our data expose a Klf4 reference cDNA variation that alters polycistronic factor stoichiometry, predicts reprogramming hallmarks, and guides comparison of compatible public data sets.