Deciphering the functions of Stromal Interaction Molecule-1 in Amelogenesis using Amelx-iCre mice

STIM1 is an ER transmembrane protein that serve as the main intracellular calcium (iCa2+) sensors in several mammalian cells. Humans with mutated STIM1 present with severely defective enamel which suggests a critical role of STIM1 protein in enamel formation. We established an ameloblast specific (Amelx-iCre) Stim1 conditional deletion mouse model (Stim1 cKO). RNAseq on micro-dissected ameloblasts from 4 weeks old mice to evaluate changes in the gene expression levels of several key ameloblast genes. Whole incisor enamel organ (EO) cell populations of 4 week old mice were extracted from 3 samples; 1 Stim1 cKO sample with complete deletion of Stim1, 1 Stim1 Heterozygous (Stim1 Het) sample with heterozygous deletion of one Stim1 allele and 1 sample with no Stim1 deletion as it was Cre negative. The Stim1 Het and Cre negative samples were used as controls. RNAseq libraries were prepared and loaded on the HiSeq 2500 high output Sequencing System (Illumina).STIM1是一种内质网（Endoplasmic Reticulum, ER）跨膜蛋白，在多种哺乳动物细胞中作为核心的细胞内钙离子（intracellular calcium, iCa²+）感受器。携带突变型STIM1的人类个体可出现严重牙釉质发育缺陷，提示STIM1蛋白在牙釉质形成过程中发挥关键作用。本研究构建了成釉细胞特异性（Amelx-iCre）的Stim1条件性敲除小鼠模型（Stim1 cKO）。为评估多个关键成釉细胞基因的表达水平变化，我们对4周龄小鼠的显微解剖成釉细胞开展了RNA测序（RNA Sequencing, RNA-seq）。实验从3份样本中提取了4周龄小鼠的完整切牙牙釉质器官（Enamel Organ, EO）细胞群：1份为完全敲除Stim1的Stim1 cKO样本，1份为单等位基因Stim1杂合缺失的Stim1杂合子（Stim1 Het）样本，剩余1份因Cre阴性而未发生Stim1缺失。本研究以Stim1杂合子样本与Cre阴性样本作为对照。完成RNA测序文库构建后，将文库上机至Illumina公司的HiSeq 2500高产出量测序系统进行测序。