先天性白内障可单独发病或与其它异常关联，损伤视力。本课题组前期在一个中国的先天性白内障合并眼前节发育不良家系中鉴定出转录因子PITX3的一个新突变。此前国际上报道了该基因6个突变，国内则无报道，其功能和机制研究十分有限。本课题拟检测该突变对蛋白的表达水平、产物大小、亚细胞定位、DNA结合和转录活性的影响；在眼科细胞系中检测PITX3对细胞增殖、周期、凋亡和分化的作用，以及该突变对这些细胞功能的影响。我们将进一步通过免疫沉淀和质谱筛选PITX3的相互作用蛋白并验证；通过对野生型和自发突变小鼠的胚胎组织进行RNA-seq分析，结合细胞中的ChIP-seq分析，筛选其下游靶基因并验证；寻找其上游转录因子；在小鼠模型中进一步验证以上相关基因或蛋白，从这些角度深入研究PITX3突变的致病机制。本研究将进一步阐明PITX3的功能和机制，为先天性白内障和眼前节发育不良的分子机理和临床治疗提供新的线索。

Congenital cataracts may occur as isolated defects or be associated with other ocular anomalies, causing visual loss or disturbance. Our previous analyses identified a novel mutation of the PITX3 gene in a Chinese family of congenital cataract with anterior segment dysgenesis, which was the first identification of PITX3 mutation in our country. PITX3 is a transcription factor and international studies have reported 6 mutations of it. However, the functions of this gene are still far from elucidation. Therefore, we plan to investigate the effect of this mutation on the expression level, product length, DNA binding ability and transcriptional activity of PITX3, and explore the role of this gene and its mutation in cell proliferation, cell cycle distribution, apoptosis and differentiation of ophthalmic cell lines. In addition, we will screen interactors of this protein through immunoprecipitation followed by mass spectrometry and validate the protein-protein interactions; identify transcriptional targets of this transcription factor by RNA-seq analyses of embryonic tissues of both wild type and aphakia(ak) mouse with the PITX3 gene spontaneously defected, and ChIP-seq analyses in cell lines, and validate the transcriptional regulation; find the upstream transcription factors of this gene; and further conform the expression level of these related genes and proteins in the mouse models. From all these perspectives, we seek to perform an in-depth investigation on the pathogenic mechanisms of PITX3 mutations. Taken together, this study may increase the knowledge of functions and mechanisms of the PITX3 gene, and provide new clues for molecular mechanistic study and clinical treatment of congenital cataract and anterior segment dysgenesis.