Glis3: a critical player in the regulation of pancreatic beta cell development

Glis3 mutant mice (Glis3zf/zf) die within the first week after birth due to overt diabetes, evidenced by hyperglycemia and hypoinsulinemia. Histopathological analysis showed that Glis3zf/zf mice develop a pancreatic phenotype with a dramatic loss of beta- (insulin) and delta- (somatostatin) cells contrasting a smaller relative loss of alpha- (glucagon), PP- (pancreatic polypeptide), and epsilon- (ghrelin) cells. Glis3zf/zf mice develop ductal cysts with decreased number of primary cilia, while the acini are not significantly affected. Gene expression profiling by microarray analysis demonstrated that the expression of terminal hormonal genes and several transcription factors important in endocrine development were significantly deregulated in Glis3zf/zf mice. During pancreatic development, Glis3 mRNA expression is induced during the secondary transition, a stage of cell lineage specification and extensive patterning. Changes in pancreatic development of Glis3zf/zf mice are noted during and after this stage; the number of cells staining positively for Ngn3, MafA, or Pdx-1 is greatly diminished. These observations indicate that Glis3 plays a key role in the development of mature beta cells. RNA samples from 2 pups for each WT or Glis3zf/zf pups were pooled, then analyzed.Glis3突变小鼠（Glis3zf/zf）因显性糖尿病于出生后第一周内死亡，其特征为高血糖（hyperglycemia）与低胰岛素血症（hypoinsulinemia）。组织病理学分析（Histopathological analysis）结果显示，该突变小鼠呈现特异性胰腺表型：β（胰岛素）细胞与δ（生长抑素）细胞发生大幅丢失，而α（胰高血糖素）、PP（胰多肽）及ε（饥饿素）细胞的相对丢失程度显著更轻。Glis3zf/zf小鼠可形成导管囊肿（ductal cysts），且初级纤毛（primary cilia）数量减少，而胰腺腺泡（acini）组织未受显著影响。通过微阵列分析（microarray analysis）开展的基因表达谱（gene expression profiling）研究表明，Glis3zf/zf小鼠的末端激素基因以及若干对内分泌发育至关重要的转录因子（transcription factors）的表达均显著失调。在胰腺发育过程中，Glis3的mRNA表达在二次过渡阶段（secondary transition，该阶段为细胞谱系特化与广泛模式化的关键时期）被诱导激活。在该阶段及之后的时期，均可观察到Glis3zf/zf小鼠的胰腺发育异常：Ngn3、MafA及Pdx-1阳性染色细胞的数量大幅减少。上述观察结果表明，Glis3在成熟β细胞的发育过程中发挥关键调控作用。本实验将每只野生型（Wild Type，WT）或Glis3zf/zf幼崽的RNA样本各2份混合后，进行后续分析。