Inducible expression of Oct-3/4 reveals synergy with Klf4 in targeting Cyclin A2 to enhance proliferation during early reprogramming.

Lamuk Zaveri, Jyotsna Dhawan

Biochemical and biophysical research communications 2022 Jan 08

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During reprogramming of somatic cells, heightened proliferation is one of the earliest changes observed. While other early events such as mesenchymal-to-epithelial transition have been well studied, the mechanisms by which the cell cycle switches from a slow cycling state to a faster cycling state are still incompletely understood. To investigate the role of Oct-3/4 in this early transition, we created a 4-Hydroxytamoxifen (OHT) dependent Oct-3/4 Estrogen Receptor fusion (OctER). We confirmed that OctER can substitute for Oct-3/4 to reprogram mouse embryonic fibroblasts to a pluripotent state. During the early stages of reprograming, Oct-3/4 and Klf4 individually did not affect cell proliferation but in combination hastened the cell cycle. Using OctER + Klf4, we found that proliferative enhancement is OHT dose-dependent, suggesting that OctER is the driver of this transition. We identified Cyclin A2 as a likely target of Oct-3/4 + Klf4. In mESC, Klf4 and Oct-3/4 bind ∼100bp upstream of Cyclin A2 CCRE, suggesting a potential regulatory role. Using inducible OctER, we show a dose-dependent induction of Cyclin A2 promoter-reporter activity. Taken together, our results suggest that Cyclin A2 is a key early target during reprogramming, and support the view that a rapid cell cycle assists the transition to pluripotency. Copyright © 2021. Published by Elsevier Inc.

Citation

Lamuk Zaveri, Jyotsna Dhawan. Inducible expression of Oct-3/4 reveals synergy with Klf4 in targeting Cyclin A2 to enhance proliferation during early reprogramming. Biochemical and biophysical research communications. 2022 Jan 08;587:29-35