Cloning and Characterization of the Hemifacial Microsomia Related Gene.

为了深入了解半面巨人(HFM)的遗传易感性和发病机制，我们分析了HFM模型小鼠的突变基因。通过对P1噬菌体文库的筛选，从突变区分离出染色体DNA。通过测序，筛选出与突变基因(S)对应的编码区。目前，我们测序了大约10kb，然后我们发现了一些与一些已知基因高度同源的区域。这些基因定位于HfM基因座上的不同位点，推测与HfM致病相关的基因(S)是一个诺贝尔基因，与已知基因具有相同的结构域结构。通过半合子之间的自然交配，获得了12枚E9.5胚胎。三个胚胎作为玫瑰色的团块死亡。PCR分析表明，三个胚胎中有一个是纯合子(另外两个胚胎由于DNA降解而无法确定它们的基因类型)。根据胎盘的大小，纯合子胚胎正常发育到e7.5。这些结果表明，HFM小鼠中被破坏的基因对正常发育起着至关重要的作用。病理筛查是在产前晚期(E13.5-17.5)进行的。除了前面描述的颧弓异常，还发现了上颌、下颌、颧骨和面部软组织的其他异常和不对称。从病理特征上进一步支持HFM小鼠是一种适合人类HFM的动物模型。

To get an insight into the genetical predisposition and pathogenesis of the hemifacial microsomia (HFM), we analyzed the mutant locus of the HFM model mouse. By the P1 phage library screening, we isolated the chromosomal DNA from the mutant region. By the DNA sequencing, we screened the coding regions that corresponded to the mutant gene(s). At present, we sequenced about 10 kb, then we identified some regions that had highly homologous sequences with those of some known genes. These genes locate the different loci with HFM locus, then it is suggested that the gene(s) that responds to HFM pathogenesis is a nobel gene, and shares some domain structures to the known genes.We investigated the phenotype of homo-zygote of HFM mouse. By the natural mating between the hemi zygotes, we obtained 12 embryos at E9.5. Three embryos died as the rosy mass. PCR analysis showed that one of three embryos was a homo-zygote (another two embryos could not determine their genotypes due to DNA degradation). According to the size of the placenta, homo-zygotes embryo developed normally to E7.5. These results showed that the gene that disrupted in HFM mouse had an essential role for the normal development.The pathological screening was carried out at the late prenatal days (E13.5-17.5). In addition to the branchial arch anomalies that described previously, other anomalies and asymmetries at the maxilla, mandible, zygoma and facial soft tissue ware identified. These observation further supported that HFM mouse is a suitable animal model for the human HFM at the point of the pathological characteristics.