Developmental Program and Genetic Disease by Six family genes.

本研究旨在揭示六个家族基因在发育中的作用，阐明包括六个家族基因的基因网络，以及六个家族基因在强直性肌营养不良症（DM 1）发病中的作用。我们对Six基因缺陷小鼠进行了分析，筛选了Six蛋白的靶基因，并对Six蛋白的协同因子Eya和Dach蛋白的分子功能进行了分析。1 Six 4/Six 5双敲除小鼠在出生后几小时内死亡，但我们没有发现任何明显的解剖学异常。6只1基因缺陷小鼠出生后立即死亡，表现出内耳、鼻子、肾脏和胸腺的缺陷形成。从E10-11观察到形态学异常。Six 1基因在这些器官的形成中起重要作用。中胚层分化过程中表达的转录因子、信号分子及其受体被鉴定为P19细胞中的推定靶点。神经系统中的转录因子和信号分子，神经递质的转运蛋白和受体蛋白。在成肌细胞中，鉴定了肌细胞生成素、肌球蛋白、肌钙蛋白、乙酰胆碱受体等骨骼肌特异性基因。在透镜上皮细胞中，鉴定出了与白内障发生有关的基因。提示这些靶基因的调节改变导致DM1.3的一些症状。我们揭示了通过CBP介导GAL 4-Eya和Dach的协同激活。CBP仅在GAL 4-Eya和Dach两者存在下结合至固定化染色质模板。我们还发现，Dach可以结合染色质以及DNA，无论GAL 4-Eya蛋白的存在。与染色质的结合亲和力高于与裸DNA的结合亲和力。Dach的保守DD 1结构域负责DNA结合活性。

This study aims to reveal roles of Six family genes in development, to elucidate gene network including Six and involvement of Six genes in pathology of myotonic dystrophy (DM1). We performed analyses of Six gene defective mice, screening of target genes of Six proteins and analyses of molecular function of Eya and Dach protein that are cooperative factors of Six protein.1 Six4/Six5 double knockout mice die within several hours after birth but we could not find any apparent anatomical anomalies. Six1 gene defective mice die just after birth and showed defective formation of inner ear, nose, kidney and thymus. The morphological abnormalities were noted from E10-11. Six1 gene is suggested to be essential for the formation of these organs.2 Target genes of Six5 proteins were identified. Transcription factors, signaling molecules and its receptors that are expressed during mesoderm differentiation were identified as putative target in P19 cells. Transcription factors and signaling molecules in nervous systems, transporters and receptor proteins of neural transmitters. In myoblasts, genes including myogenin, myosin, troponin, acetylcholine receptors that arespecific to skeletal muscle were identified. In lens epithelial cells, genes that had been shown to be involved in cataractogenesis were identified. It is suggested that altered regulation of these target genes leads to some symptoms of DM1.3 We revealed that cooperative activation by GAL4-Eya and Dach is mediated through CBP. CBP bound to an immobilized chromatin template only in the presence of both GAL4-Eya and Dach. We also found that Dach can bind to chromatin as well as DNA regardless of the presence of GAL4-Eya protein. The binding affinity to chromatin was higher than that to naked DNA. The conserved DD1 domain of Dach is responsible for the DNA binding activity.