Ectopic expression of Oct4, Sox2, Klf4 and c-Myc can reprogram somatic cells into induced pluripotent stem cells (iPSCs). Attempts to identify genes or chemicals that can functionally replace each of these four reprogramming factors have revealed that exogenous Oct4 is not necessary for reprogramming under certain conditions or in the presence of alternative factors that can regulate endogenous Oct4 expression. For example, polycistronic expression of Sox2, Klf4 and c-Myc can elicit reprogramming by activating endogenous Oct4 expression indirectly. Experiments in which the reprogramming competence of all other Oct family members tested and also in different species have led to the decisive conclusion that Oct proteins display different reprogramming competences and species-dependent reprogramming activity despite their profound sequence conservation. We discuss the roles of the structural components of Oct proteins in reprogramming and how donor cell epigenomes endow Oct proteins with different reprogramming competences.

Oct4、Sox2、Klf4 和 c-Myc 的异位表达可以将体细胞重编程为诱导多能干细胞 (iPSC)。鉴定可以在功能上替代这四种重编程因子的基因或化学物质的尝试表明，在某些条件下或在存在可调节内源性 Oct4 表达的替代因子的情况下，外源性 Oct4 不是重编程所必需的。例如，Sox2、Klf4 和 c-Myc 的多顺反子表达可以通过间接激活内源性 Oct4 表达来引发重编程。对所有其他 Oct 家族成员的重编程能力以及在不同物种中进行测试的实验得出了决定性结论，即 Oct 蛋白显示出不同的重编程能力和物种依赖性重编程活性，尽管它们具有深刻的序列保守性。我们讨论了 Oct 蛋白的结构成分在重编程中的作用，以及供体细胞表观基因组如何赋予 Oct 蛋白不同的重编程能力。