Taste papilla cell differentiation requires the regulation of secretory protein production by ALK3-BMP signaling in the tongue mesenchyme

Taste papillae are specialized organs, each of which comprises an epithelial wall hosting taste buds and a core of mesenchymal tissue. In the present study, we report that during early taste papilla development in mouse embryos, bone morphogenetic protein (BMP) signaling mediated by type 1 receptor ALK3 in the tongue mesenchyme is required for the epithelial Wnt/beta-catenin activity and taste papilla differentiation. Separated mesenchymal and epithelial tissues from E12.0 Cre- littermate control and mesenchyme specific Wnt1-Cre mediated Alk3 conditional knock out (cKO) tongues were immersed in Trizol solution (15596018, Life Technologies) for RNA extraction using the RNeasy Plus kit (74136, Qiagen). For each experimental condition, a total of nine mesenchymal and epithelial tissues (pooled three tissues x three replicates) were used. RNA concentrations were measured using Nanodrop 8000 spectrophotometer (ThermoFisher Scientific). RNA sequencing was performed in Georgia Genomics and Bioinformatics Center at the University of Georgia using the NextSeq 500 system (Illumina)味觉乳头（Taste papillae）属于特化器官，每个味觉乳头均由承载味蕾的上皮壁与间充质组织核心组成。本研究报道，在小鼠胚胎味觉乳头的早期发育阶段，舌间充质中由1型受体ALK3介导的骨形态发生蛋白（bone morphogenetic protein, BMP）信号通路，对于上皮细胞的Wnt/β-连环蛋白活性与味觉乳头分化是必需的。我们将E12.0 Cre阴性同窝对照小鼠，以及经间充质特异性Wnt1-Cre介导的Alk3条件性敲除（conditional knock out, cKO）小鼠的舌组织分离出间充质与上皮组分后，将其置于Trizol试剂（15596018, Life Technologies）中，使用RNeasy Plus试剂盒（74136, Qiagen）进行RNA提取。每个实验条件共使用9份间充质与上皮组织样本，即每3份组织混合为1个重复，共设置3个重复。RNA浓度采用Nanodrop 8000分光光度计（ThermoFisher Scientific）进行测定。RNA测序工作在佐治亚大学佐治亚基因组与生物信息学中心完成，使用Illumina的NextSeq 500测序系统。