Table 1.

Chromatin-modifying enzymes required for normal islet development or function.

Enzyme	Mechanism of action	Effect on transcription	Effect of deletion on pancreas or islets in mice
Brg1	Part of SWI/SNF complex; nucleosome remodeling; in the pancreas a Pdx1 coactivator	Silencing or activating	Hypoplastic pancreas when deleted early
Dicer	ncRNA processing	Silencing or activating	Degranulation and loss of β-cells
Dnmt1	Maintenance of CpG methylation	Usually silencing	Hypoplastic pancreas when deleted early
Dnmt3	De novo CpG methylation	Usually silencing	Dysregulation of glucose-stimulated insulin secretion
Ezh22	Part of PRC2; methylation of lysine 27 on H3 to H3K27	Silencing	Increased number of endocrine progenitors and mature β-cells