Rozario Tania, Dzamba Bette, Weber Gregory F, Davidson Lance A, DeSimone Douglas W
Department of Cell Biology and the Morphogenesis and Regenerative Medicine Institute, University of Virginia, PO Box 800732, School of Medicine, Charlottesville, VA 22908, USA.
Dev Biol. 2009 Mar 15;327(2):386-98. doi: 10.1016/j.ydbio.2008.12.025. Epub 2008 Dec 30.
This study demonstrates that proper spatiotemporal expression and the physical assembly state of fibronectin (FN) matrix play key roles in the regulation of morphogenetic cell movements in vivo. We examine the progressive assembly and 3D fibrillar organization of FN and its role in regulating cell and tissue movements in Xenopus embryos. Expression of the 70 kD N-terminal fragment of FN blocks FN fibril assembly at gastrulation but not initial FN binding to integrins at the cell surface. We find that fibrillar FN is necessary to maintain cell polarity through oriented cell division and to promote epiboly, possibly through maintenance of tissue-surface tension. In contrast, FN fibrils are dispensable for convergence and extension movements required for axis elongation. Closure of the migratory mesendodermal mantle was accelerated in the absence of a fibrillar matrix. Thus, the macromolecular assembly of FN matrices may constitute a general regulatory mechanism for coordination of distinct morphogenetic movements.
本研究表明，纤连蛋白（FN）基质的适当时空表达和物理组装状态在体内调节形态发生细胞运动中起关键作用。我们研究了FN的逐步组装和三维纤维组织及其在非洲爪蟾胚胎中调节细胞和组织运动的作用。FN 70 kD N端片段的表达在原肠胚形成时阻断了FN纤维的组装，但不影响初始FN与细胞表面整合素的结合。我们发现，纤维状FN对于通过定向细胞分裂维持细胞极性以及促进外包可能是必需的，这可能是通过维持组织表面张力实现的。相比之下，FN纤维对于轴伸长所需的汇聚和延伸运动是可有可无的。在没有纤维状基质的情况下，迁移的中内胚层套膜的闭合加速。因此，FN基质的大分子组装可能构成协调不同形态发生运动的一般调节机制。
