GLIS3 and Hypoinsulinemia: To investigate whether hypoinsulinemia contributed to the inhibition of thyroid follicular cell proliferation in ubiquitous Glis3KO thyroid phenotype, we analyzed the thyroid gland phenotype in thyroid-selective Glis3 knockout mice, Glis3-Pax8Cre (referred as conditional knockout or CKO in the Figures), in which Pax8Cre efficiently (> 90%) deleted exon 5 in Glis3 in the thyroid gland, but not in the pancreas (Fig. 5A and Supplementary Fig. 5A).