Fig. 6. Postnatal restriction of NNAT in a subset of beta cells is at least partially driven by the de novo methyltransferase, DNMT3A.

(a) Representative confocal microscopy of pancreatic cryosections from mice with conditional deletion of DNMT3A under the control of the Pdx1 promoter (Pdx1-Cre⁺ Dnmt3a^fl/fl) vs control (Pdx1-Cre⁻ Dnmt3a^fl/fl) mice at postnatal (P) day 6. Sections were immunostained with antibodies against endogenous neuronatin (NNAT, green) and insulin (INS, red). (b) Quantification of NNAT⁺ beta cells from images shown in a, expressed as NNAT/INS co-positive cells as a percentage of total INS-positive cells. Scale bar = 50μm (n = 8 mice per genotype, unpaired Students t test, ** P < 0.01). (c) Representative confocal microscopy of pancreatic cryosections from P56 (8 week old) wild type mice on a C57BL/6J background immunostained with antibodies against endogenous neuronatin (NNAT, green) and H3K27me3 (red). Scale bar = 100μm, n = 3 mice. Nuclei are visualised with DAPI. Representative images from three independent experiments and breeding pairs.