Tissue fusion is a critical process that is repeated in multiple contexts during embryonic development and shares common attributes to processes such as wound healing and metastasis. Ocular coloboma is a developmental eye disorder that presents as a physical gap in the ventral eye, and is a major cause of childhood blindness. Coloboma results from fusion failure between opposing ventral retinal epithelia, but there are major knowledge gaps in our understanding of this process at the molecular and cell behavioural levels. Here we catalogue the expression of cell adhesion proteins: N-cadherin, E-cadherin, R-cadherin, ZO-1, and the EMT transcriptional activator and cadherin regulator SNAI2, in the developing chicken embryonic eye. We find that fusion pioneer cells at the edges of the fusing optic fissure have unique and dynamic expression profiles for N-cad, E-cad and ZO-1, and that these are temporally preceded by expression of SNAI2. This highlights the unique properties of these cells and indicates that regulation of cell adhesion factors may be a critical process in optic fissure closure.

组织融合是胚胎发育过程中在多种情况下重复的关键过程，并且与伤口愈合和转移等过程具有共同的属性。眼缺损是一种发育性眼部疾病，表现为腹眼的物理间隙，是儿童失明的主要原因。缺损是由相对的腹侧视网膜上皮细胞之间的融合失败引起的，但我们在分子和细胞行为水平上对这一过程的理解存在重大知识差距。在这里，我们对发育中的鸡胚眼中细胞粘附蛋白的表达进行了分类：N-钙粘蛋白、E-钙粘蛋白、R-钙粘蛋白、ZO-1以及EMT转录激活剂和钙粘蛋白调节剂SNAI2。我们发现融合视神经裂边缘的融合先驱细胞具有独特且动态的 N-cad、E-cad 和 ZO-1 表达谱，并且这些细胞在时间上先于 SNAI2 表达。这凸显了这些细胞的独特特性，并表明细胞粘附因子的调节可能是视裂隙闭合的关键过程。