Chromatin‐associated proteins are essential for the specification and maintenance of cell identity. They exert these functions through modulating and maintaining transcriptional patterns. To elucidate the functions of the Jmjd2 family of H3K9/H3K36 histone demethylases, we generated conditional Jmjd2a/Kdm4a, Jmjd2b/Kdm4b and Jmjd2c/Kdm4c/Gasc1 single, double and triple knockout mouse embryonic stem cells (ESCs). We report that while individual Jmjd2 family members are dispensable for ESC maintenance and embryogenesis, combined deficiency for specifically Jmjd2a and Jmjd2c leads to early embryonic lethality and impaired ESC self‐renewal, with spontaneous differentiation towards primitive endoderm under permissive culture conditions. We further show that Jmjd2a and Jmjd2c both localize to H3K4me3‐positive promoters, where they have widespread and redundant roles in preventing accumulation of H3K9me3 and H3K36me3. Jmjd2 catalytic activity is required for ESC maintenance, and increased H3K9me3 levels in knockout ESCs compromise the expression of several Jmjd2a/c targets, including genes that are important for ESC self‐renewal. Thus, continual removal of H3K9 promoter methylation by Jmjd2 demethylases represents a novel mechanism ensuring transcriptional competence and stability of the pluripotent cell identity.
A set of newly generated conditional deletion models shows that histone demethylases Jmjd2a and Jmjd2c are highly redundant and that their regulation of H3K9 promoter methylation is vital for ESC self‐renewal.
Knockout of Jmjd2 demethylases reveals redundant and essential functions of Jmjd2a and Jmjd2c in early embryogenesis.
Loss of both Jmjd2a and Jmjd2c impairs ESC self‐renewal in 2i as well as serum culture.
Jmjd2a and Jmjd2c both localize to H3K4me3‐marked TSSs and continuously prevent accumulation of H3K9me3 and H3K36me3.
In the absence of Jmjd2a/c catalytic activity, increased H3K9me3 levels at TSSs compromise the expression of genes required for ESC maintenance.
- Received October 20, 2015.
- Revision received April 15, 2016.
- Accepted May 6, 2016.
- © 2016 The Authors
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