Yuan S, Schoenwolf G C
Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA.
Development. 1999 Jun;126(11):2461-73. doi: 10.1242/dev.126.11.2461.
Lateral blastoderm isolates (LBIs) at the late gastrula/early neurula stage (i.e., stage 3d/4) that lack Hensen's node (organizer) and primitive streak can reconstitute a functional organizer and primitive streak within 10-12 hours in culture. We used LBIs to study the initiation and regionalization of the body plan. A complete body plan forms in each LBI by 36 hours in culture, and normal craniocaudal, dorsoventral, and mediolateral axes are re-established. Thus, reconstitution of the organizer is sufficient to re-establish a fully patterned body plan. LBIs can be modified so that reconstitution of the organizer does not occur. In such modified LBIs, tissue-type specific differentiation (with the exception of heart differentiation) and reconstitution of the body plan fail to occur. Thus, the reconstitution of the organizer is not only sufficient to re-establish a fully patterned body plan, it is also required. Finally, our results show that formation and patterning of the heart is under the control of the organizer, and that such control is exerted during the early to mid-gastrula stages (i.e., stages 2-3a), prior to formation of the fully elongated primitive streak.
处于原肠胚后期/神经胚早期（即3d/4期）、缺乏亨氏结（组织者）和原条的侧胚盘分离物（LBI）在培养10 - 12小时内能够重建功能性的组织者和原条。我们利用LBI来研究体轴的起始和区域化。在培养36小时时，每个LBI中都会形成完整的体轴，并且重建了正常的头尾轴、背腹轴和内外侧轴。因此，组织者的重建足以重新建立一个完全模式化的体轴。可以对LBI进行改造，使得组织者无法重建。在这种改造后的LBI中，组织类型特异性分化（心脏分化除外）和体轴重建均无法发生。因此，组织者的重建不仅足以重新建立一个完全模式化的体轴，而且是必需的。最后，我们的结果表明，心脏的形成和模式化受组织者控制，并且这种控制在完全伸长的原条形成之前的原肠胚早期至中期（即2 - 3a期）发挥作用。
