Campbell Hugh D, Fountain Shelley, McLennan Ian S, Berven Leise A, Crouch Michael F, Davy Deborah A, Hooper Jane A, Waterford Kynan, Chen Ken-Shiung, Lupski James R, Ledermann Birgit, Young Ian G, Matthaei Klaus I
Molecular Genetics and Evolution Group, Research School of Biological Sciences, Australian National University, Canberra, ACT 2601, Australia.
Mol Cell Biol. 2002 May;22(10):3518-26. doi: 10.1128/MCB.22.10.3518-3526.2002.
The Drosophila melanogaster flightless I gene is required for normal cellularization of the syncytial blastoderm. Highly conserved homologues of flightless I are present in Caenorhabditis elegans, mouse, and human. We have disrupted the mouse homologue Fliih by homologous recombination in embryonic stem cells. Heterozygous Fliih mutant mice develop normally, although the level of Fliih protein is reduced. Cultured homozygous Fliih mutant blastocysts hatch, attach, and form an outgrowing trophoblast cell layer, but egg cylinder formation fails and the embryos degenerate. Similarly, Fliih mutant embryos initiate implantation in vivo but then rapidly degenerate. We have constructed a transgenic mouse carrying the complete human FLII gene and shown that the FLII transgene is capable of rescuing the embryonic lethality of the homozygous targeted Fliih mutation. These results confirm the specific inactivation of the Fliih gene and establish that the human FLII gene and its gene product are functional in the mouse. The Fliih mouse mutant phenotype is much more severe than in the case of the related gelsolin family members gelsolin, villin, and CapG, where the homozygous mutant mice are viable and fertile but display alterations in cytoskeletal actin regulation.
果蝇的无翅I基因对于合胞体胚盘的正常细胞化是必需的。在秀丽隐杆线虫、小鼠和人类中存在无翅I的高度保守同源物。我们通过胚胎干细胞中的同源重组破坏了小鼠同源物Fliih。杂合的Fliih突变小鼠发育正常，尽管Fliih蛋白水平降低。培养的纯合Fliih突变胚泡孵化、附着并形成向外生长的滋养层细胞层，但卵圆柱形成失败且胚胎退化。同样，Fliih突变胚胎在体内开始着床，但随后迅速退化。我们构建了携带完整人类FLII基因的转基因小鼠，并表明FLII转基因能够挽救纯合靶向Fliih突变的胚胎致死性。这些结果证实了Fliih基因的特异性失活，并确定人类FLII基因及其基因产物在小鼠中具有功能。Fliih小鼠突变体表型比相关凝溶胶蛋白家族成员凝溶胶蛋白、绒毛蛋白和CapG的情况严重得多，在后者中，纯合突变小鼠是存活且可育的，但在细胞骨架肌动蛋白调节方面表现出改变。
