Roles of the MFH-1 gene and WT 1 gene in kidney development

1993年，我们分离了叉头基因家族中的MFH-1基因。这个家族正在壮大，在小鼠中已知的基因超过20个。MFH-1基因在体节中胚层表达，随后在硬节中强烈表达。MFH-1基因在胚胎干细胞中的同源重组法构建了MFH-1基因敲除小鼠模型。首先，我们克隆了小鼠基因组MFH-1基因，并确定了其基因组结构。我们发现它没有内含子。我们通过用新抗性盒替换外显子来制备靶向载体，并通过电穿孔将其引入ES细胞。在480个新霉素和更昔洛韦抗性克隆中，6个被鉴定为同源重组体。我们通过将它们注射到胚泡中来制造嵌合体小鼠，并通过嵌合体小鼠和野生B6小鼠交配来获得杂合子小鼠。杂合子无症状。然而，纯合子在出生后10分钟内死亡。纯合子在几个组织中有异常。在这里，我们重点关注肾脏的表型。纯合子的肾脏大小是野生型的一半。组织学上肾小球、肾小管细胞和血管正常。其次，我们克隆了人基因组MFH-1基因，并测定了其核苷酸序列。我们发现人MFH-1蛋白长501个氨基酸，并且人和小鼠的叉状结构域的氨基酸序列相同。小鼠MFH-1蛋白与人MFH-1蛋白的同源性为94%。利用这些抗体，我们发现MFH-1蛋白在软骨肉瘤、骨肉瘤和Wilms肿瘤细胞系中表达。

We isolated the MFH-1 gene as one of the forkhead gene family in 1993. The family are growing and more than 20 genes are known in mice. The MFH-1 gene is expressed at the somitic mesoderm and later expressed strongly in the sclerotome. It is also expressed in the developing metanephros and later on in the glomerulus after birth.We made knockout mice of the MFH-1 gene by homologous recombination in the ES cells. First, we cloned the mouse genomic MFH-1 gene and determined its genomic structure. We found that it has no introns. We made a targeting vector by replacing the exon with neo-resistance cassette and introduced it into ES cells by electroporation. Out of 480 neomycin- and gancyclovir-resistant clones, 6 were identified to be homologous recombinants. We made chimera mice by injecting them into a blastocyst and obtained heterozygotic mice by mating chimera mice and wild B6 mice. The heterozygotes were asymptomatic. However, homozygotes were dead within ten minutes after birth.Homozygotes had abnormalities in several tissues. Here we focused the phenotype of kidneys. The size of kidneys in homozygotes was half that of the wild-type. Histologically the glomerulus, renal tubular cells and blood vesssels were present normally. But dilated renal calces were seen in homozygotes.Next, we cloned the human genomic MFH-1 gene and determined its nucleotide sequence. We found that human MFH-1 protein is 501 amino acids long and the amino acid sequence of the forkheah domain is identical in human and mouse. Identity of the mouse and human MFH-1 protein is 94%.We also made monoclonal antibodies against the human MFH-1 protein. Using thses antibodies, we found that the MFH-1 protein is expressed in chondrosarcoma, osteosarcoma and Wilms tumor cell lines.