Tazumi Shunsuke, Yabe Shigeharu, Yokoyama Jun, Aihara Yuko, Uchiyama Hideho
International Graduate School of Arts and Sciences, Yokohama City University, Yokohama, Japan.
Dev Dyn. 2008 Dec;237(12):3749-61. doi: 10.1002/dvdy.21791.
T-box transcription factor tbx6 and basic-helix-loop-helix transcription factor pMesogenin1 are reported to be involved in paraxial mesodermal differentiation. To clarify the relationship between these genes in Xenopus laevis, we isolated pMesogenin2, which showed high homology with pMesogenin1. Both pMesogenin1 and 2 appeared to be transcriptional activators and were induced by a hormone-inducible version of Xtbx6 without secondary protein synthesis in animal cap assays. The pMesogenin2 promoter contained three potential T-box binding sites with which Xtbx6 protein was shown to interact, and a reporter gene construct containing these sites was activated by Xtbx6. Xtbx6 knockdown reduced pMesogenin1 and 2 expressions, but not vice versa. Xtbx6 and pMesogenin1 and 2 knockdowns caused similar phenotypic abnormalities including somite malformation and ventral body wall muscle hypoplasia, suggesting that Xtbx6 is a direct regulator of pMesogenin1 and 2, which are both involved in somitogenesis and myogenesis including that of body wall muscle in Xenopus laevis.
据报道，T盒转录因子tbx6和碱性螺旋-环-螺旋转录因子pMesogenin1参与近轴中胚层分化。为了阐明非洲爪蟾中这些基因之间的关系，我们分离出了与pMesogenin1具有高度同源性的pMesogenin2。pMesogenin1和2似乎都是转录激活因子，并且在动物帽实验中，它们在没有二次蛋白质合成的情况下被激素诱导型Xtbx6诱导。pMesogenin2启动子包含三个潜在的T盒结合位点，Xtbx6蛋白显示可与这些位点相互作用，并且含有这些位点的报告基因构建体被Xtbx6激活。敲低Xtbx6会降低pMesogenin1和2的表达，但反之则不然。敲低Xtbx6、pMesogenin1和2会导致相似的表型异常，包括体节畸形和腹侧体壁肌肉发育不全，这表明Xtbx6是pMesogenin1和2的直接调节因子，二者均参与非洲爪蟾的体节发生和肌发生，包括体壁肌肉的肌发生。
