The nuclear interactome of 14-3-3zeta reveals its critical roles for genome accessibility during early stages of adipogenesis

Little is known about the molecular factors that tightly coordinate sequential actions of adipogenic cellular pathways that occur during the early stages of adipocyte precursor cells (APCs) differentiation. We previously established the scaffold protein, 14-3-3?, as a critical regulator of adipogenesis (Lim et al., Nat Commun., 2015). Our proteomic analysis performed in the present study suggested functional interactions between 14-3-3? and epigenetic effectors, such as DNMTs and HDACs, during the intial stages of APC differentiation. To assess if or how 14-3-3? influences chromatin accessibility in differentiating APCs, we performed ATAC-seq on 3T3-L1 preadipocytes that were transfected with a control, non-targeting siRNA (siCon) or siRNA against Ywhaz (sizeta), the gene encoding 14-3-3? (using either a Ywhaz-targeting or a control siRNA), followed by differentiation with the adipogenic cocktail (MDI) for 0h, 24h and 48h. Our ATAC-seq analysis revealed that 14-3-3? depletion impacted the accessibility of up to 1,244 chromatin regions corresponding in part to adipogenic genes, promoters, and enhancers during the initial 48 hours of differentiation. In conclusion, we report 14-3-3? as a key epigenetic modulator during induction of adipogenesis. Overall design: To explore how 14-3-3zeta may influence chromatin accessibility during adipogenesis, we used murine 3T3-L1 pre-adipocytes that were transfected with siRNA against Ywhaz, the gene encoding 14-3-3zeta, followed by isolation of nuclei for downstream ATAC-Seq.