Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Program in Craniofacial Biology, University of California, San Francisco, 513 Parnassus Avenue, Box 0512, San Francisco, CA 94143, USA; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA.
Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Program in Craniofacial Biology, University of California, San Francisco, 513 Parnassus Avenue, Box 0512, San Francisco, CA 94143, USA; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94143, USA; Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA.
Cell Rep. 2022 Mar 15;38(11):110510. doi: 10.1016/j.celrep.2022.110510.
The mechanisms coupling fate specification of distinct tissues to their physical separation remain to be understood. The trachea and esophagus differentiate from a single tube of definitive endoderm, requiring the transcription factors SOX2 and NKX2-1, but how the dorsoventral site of tissue separation is defined to allocate tracheal and esophageal cell types is unknown. Here, we show that the EPH/EPHRIN signaling gene Efnb2 regulates tracheoesophageal separation by controlling the dorsoventral allocation of tracheal-fated cells. Ventral loss of NKX2-1 results in disruption of separation and expansion of Efnb2 expression in the trachea independent of SOX2. Through chromatin immunoprecipitation and reporter assays, we find that NKX2-1 likely represses Efnb2 directly. Lineage tracing shows that loss of NKX2-1 results in misallocation of ventral foregut cells into the esophagus, while mosaicism for Nkx2-1 generates ectopic NKX2-1/EPHRIN-B2 boundaries that organize ectopic tracheal separation. Together, these data demonstrate that NKX2-1 coordinates tracheal specification with tissue separation through the regulation of EPHRIN-B2 and tracheoesophageal cell sorting.
不同组织命运特化与其物理分离的机制仍有待理解。气管和食管由一个确定的内胚层管分化而来，需要转录因子 SOX2 和 NKX2-1，但组织分离的背腹位置如何确定以分配气管和食管细胞类型尚不清楚。在这里，我们表明 Eph/Ephrin 信号基因 Efnb2 通过控制气管命运细胞的背腹分配来调节气管食管分离。NKX2-1 的缺失会导致分离中断，并且 Efnb2 的表达在气管中独立于 SOX2 而扩张。通过染色质免疫沉淀和报告基因检测，我们发现 NKX2-1 可能直接抑制 Efnb2。谱系追踪显示，NKX2-1 的缺失会导致腹侧前肠细胞错误分配到食管中，而 Nkx2-1 的嵌合性则产生异位 NKX2-1/Ephrin-B2 边界，从而组织异位气管分离。总之，这些数据表明，NKX2-1 通过调节 Ephrin-B2 和气管食管细胞分选，协调气管特化与组织分离。
