Silencing of the somatic cell-type specific genes is a critical yet poorly understood step in reprogramming. To uncover pathways that maintain cell identity, we performed a reprogramming screen using inhibitors of chromatin factors. Here we identify acetyl-lysine competitive inhibitors targeting the bromodomains of coactivators CBP and EP300 as potent enhancers of reprogramming. These inhibitors accelerate reprogramming, are critical during its early stages and, when combined with DOT1L inhibition, enable efficient derivation of human iPSCs with OCT4 and SOX2. In contrast, catalytic inhibition of CBP/EP300 prevents iPSC formation, suggesting distinct functions for different co-activator domains in reprogramming. CBP/EP300 bromodomain inhibition decreases somatic-specific gene expression, histone H3 lysine 27 acetylation (H3K27Ac) and chromatin accessibility at target promoters and enhancers. The master Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:

Fibroblasts from a Familial Mediterranean Fever (FMF) patient were reprogrammed with episomal vectors by using the Neon Transfection System for the generation of integration-free induced pluripotent stem cells (iPSCs). The resulting iPSC line was characterized to determine the expression of pluripotency markers, proper differentiation into three germ layers, the presence of normal chromosomal structures as well as the lack of genomic integration. A homozygous missense mutation in the MEFV gene (p.Met694Val), which lead to typical FMF phenotype, was shown to be present in the generated iPSC line.

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