Molecular machanism of the MFH-1 gene in, the aoortic arch formation, Skeletogenesis and kidney formation

第一年我们研究了MFH-1和Pax 1基因在骨骼发生中的关系。结果表明，MFH-1和Pax 1在硬节的腹侧区和侧区均有表达，且MFH-1的表达依赖于脊索。MFH-1/Pax 1双基因敲除小鼠的成骨细胞增殖能力明显低于单基因敲除小鼠，表明MFH-1和Pax 1在成骨细胞中起协同作用。在第二年，我们研究了MFH-1和内皮素受体A（ETA）基因在主动脉弓形成中的关系。MFH-1和ETA在相似的区域和相似的时间表达，以及两个基因敲除小鼠均表现出主动脉弓中断的结果，似乎这两个基因之间存在上游-下游关系。然而，使用敲除小鼠的原位杂交实验表明，MFH-1和ETA可能在主动脉弓形成中独立起作用。在过去的一年里，我们调查了MFH 1/ETA双基因敲除小鼠的表型。我们发现双基因敲除小鼠在胚胎11.5天时死于心力衰竭。在对MFH-1基因在骨分化中作用的研究中，我们发现MFH-1基因在骨形成前表达较强，在骨分化后表达减弱。接下来，我们确定了MFH-1基因是否被诱导，以响应植入含有骨形态发生蛋白（BMP）的珠在发育中的小鼠肢体。结果表明，MFH-1的表达在离微珠较远的部位增强。这些数据共同表明，BMP直接或间接地调节MFH-1基因在小鼠四肢骨形成。

In the first year we investigated the relationship between the MFH-1 and Pax1 genes in skeletogenesis. We obtained the results that MFH-1 and Pax1 were expressed in the ventral and lateral areas of sclerotome and that MFH-1 expression is dependent on the notochord. We also investigated that the MFH-1/Pax1 double knockout mice showed more severe defects in cell proliferative ability in the sclerotomal cells than either single knockout mouse did.These results showed that MFH-1 and Pax1 play a cooperative role in the sclerotome to make vertebraes. In the second year, we investigated the relationship between the MFH-1 and endothelin receptor A (ETA) genes in the aortic arch formation. The results that MFH-1 and ETA were expressed at the similar areas and at similar time and that both knockout mice showed interrupted aortic arch seem likely that there is an upstream-down stream relationship between these two genes. However, the in situ hybridization experiments using the knockout mice indicated that MFH-1 and ETA might act independently in the aortic arch formation. In the last year, we investigated the phenotypes of MFH 1/ETA double knockout mice. We found that the double knockout mice died at the embryonic day of 11.5 day due to heart failure. In the study on the role of MFH-1 gene in the bone differentiation, we found that the MFH-1 gene was expressed strongly just before the bone formation and its expression decreased after the bone was differentiated. Next, we determined whether the MFH-1 gene was induced in response to the implanted beads containing the bone morphogenetic protein (BMP) in the developing mouse limbs. The result showed that the MFH-1 expression was enhanced at a little remote site from the beads. The data together indicate that BMP regulates the MFH-1 gene directly or indirectly in the bone formation of mouse limbs.