Malashichev Yegor, Christ Bodo, Pröls Felicitas
Department of Vertebrate Zoology, Faculty of Biology and Soil Sciences, St Petersburg State University, Universitetskaya nab, St Petersburg, Russia.
Cell Tissue Res. 2008 Mar;331(3):595-604. doi: 10.1007/s00441-007-0556-6. Epub 2007 Dec 18.
The pelvic girdle is composed of three skeletal elements: ilium, pubis, and ischium. In comparison with other parts of the postcranial skeleton, its development is not well known to date. To elucidate the embryonic origin of the avian pelvic girdle and the signaling centers that control its development, we have performed extirpation and quail-to-chick grafting experiments. The results reveal that the entire pelvic girdle originates from the somatopleure at somite levels 26 to 35. No somitic cell contribution to skeletal elements of the pelvis has been detected. Removal of the surface ectoderm covering the lateral plate mesoderm has revealed that ectodermal signals control the development of the pelvic girdle, especially the formation of the pubis and ischium. The impaired development of the ischium and pubis correlates with the downregulation of Pax1 and Alx4, two transcription factors that control the normal development of the ischium and pubis. Although of somatopleural origin, the development of the ilium depends on somitic signals. Insertion of a barrier between somites and somatopleure disrupts the expression of Emx2 and prevents normal development of the ilium but does not affect the expression of Pax1 or Alx4 and the development of the pubis and ischium. Thus, the development of the ilium, but not of the pubis and ischium, depends on somitic and ectodermal signals.
髂骨、耻骨和坐骨。与颅后骨骼的其他部分相比，其发育至今仍不太为人所知。为了阐明鸟类骨盆带的胚胎起源以及控制其发育的信号中心，我们进行了切除和鹌鹑-鸡移植实验。结果表明，整个骨盆带起源于第26至35体节水平的体壁。未检测到体节细胞对骨盆骨骼成分的贡献。去除覆盖侧板中胚层的表面外胚层后发现，外胚层信号控制着骨盆带的发育，尤其是耻骨和坐骨的形成。坐骨和耻骨发育受损与Pax1和Alx4这两种控制坐骨和耻骨正常发育的转录因子的下调有关。虽然髂骨起源于体壁，但它的发育依赖于体节信号。在体节和体壁之间插入一个屏障会破坏Emx2的表达并阻止髂骨的正常发育，但不会影响Pax1或Alx4的表达以及耻骨和坐骨的发育。因此，髂骨的发育依赖于体节和外胚层信号，而耻骨和坐骨的发育则不然。
