Expression data from mesodermal Tbx1-knockout ears at E12.5

The T-box transcription factor Tbx1 is expressed in the otic vesicle and surrounding periotic mesenchyme during inner ear development. Mesenchymal Tbx1 is essential for inner ear development, with conditional mutants displaying defects in both auditory and vestibular systems. We have previously identified reduced expression of retinoic acid metabolic genes in the periotic mesenchyme of mesoderm conditional Tbx1 mutants, using the T-Cre mouse line, implicating retinoic acid in mesenchymal-epithelial signaling downstream of Tbx1 in the periotic mesenchyme. In order to identify downstream effectors of mesenchymal-epithelial signaling downstream of mesenchymal Tbx1, we have utilized a gene profiling approach comparing embryonic day 12.5 periotic tissue from T-Cre-mediated conditional Tbx1 mutants (Mest-KO) and conditional heterozygous control litter mates (control). E12.5 T-Cre-mediated conditional Tbx1 mutants (Mest-KO) and control (T-Cre conditional Tbx1 heterozygotes) embryos were microdissected to isolate the otic vesicle and surrounding periotic mesenchyme. Left and right tissue from each individual embryo was pooled, and 5 control and 5 mutant embryos were analyzed on individual microarrays using Affymetrix Mouse Gene ST 1.0 chips.T-box转录因子Tbx1（T-box transcription factor Tbx1）在小鼠内耳发育过程中表达于听泡及其周围的耳周间充质内。耳周间充质中的Tbx1对于内耳发育不可或缺，携带条件性突变的小鼠其听觉与前庭系统均出现发育缺陷。我们此前利用T-Cre小鼠品系，在中胚层条件性Tbx1突变体的耳周间充质中检测到视黄酸代谢相关基因的表达水平显著下调，这提示视黄酸参与了耳周间充质内Tbx1下游的间充质-上皮信号转导通路。为鉴定间充质来源Tbx1所调控的间充质-上皮信号转导通路的下游效应因子，我们采用基因表达谱分析策略，比较了T-Cre介导的条件性Tbx1突变体（命名为Mest-KO）与条件性杂合对照同窝胚胎的胚胎第12.5天（E12.5）耳周组织。我们对E12.5的T-Cre介导条件性Tbx1突变体（Mest-KO）及对照（T-Cre条件性Tbx1杂合子）胚胎进行显微解剖，分离得到听泡及周围的耳周间充质组织。将每枚胚胎的左右两侧组织合并，使用Affymetrix公司小鼠基因ST 1.0芯片（Affymetrix Mouse Gene ST 1.0 chips），通过单张微阵列分别对5枚对照组胚胎与5枚突变体胚胎开展基因表达谱分析。