Mercola Mark
Stem Cell and Regeneration Program, The Burnham Institute, 10901 N Torrey Pines Road, La Jolla, CA 92037, USA.
J Cell Sci. 2003 Aug 15;116(Pt 16):3251-7. doi: 10.1242/jcs.00668.
The striking left-right asymmetry of visceral organs is known to depend on left- and right-side-specific cascades of gene expression during early embryogenesis. Now, developmental biologists are characterizing the earliest steps in asymmetry determination that dictate the sidedness of asymmetric gene expression. The proteins and structures involved control fascinating physiological processes, such as extracellular fluid flow and membrane voltage potential and yet little is known about how their activities are coordinated to control laterality. By analogy with intercellular signalling in certain epithelial and endothelial cells, however, it is reasonable to speculate that at least three of these players, monocilia, gap junction communication and the Ca2+ channel polycystin-2, participate in a signalling pathway that propagates left-right cues through multicellular fields.
已知内脏器官显著的左右不对称性取决于胚胎早期发育过程中左右侧特异性的基因表达级联反应。如今，发育生物学家正在确定不对称性决定过程中最早的步骤，这些步骤决定了不对称基因表达的方向。所涉及的蛋白质和结构控制着迷人的生理过程，如细胞外液流动和膜电压电位，但对于它们的活动如何协调以控制左右不对称性却知之甚少。然而，通过与某些上皮细胞和内皮细胞中的细胞间信号传导进行类比，可以合理推测这些参与者中至少有三个，即单纤毛、间隙连接通讯和钙离子通道多囊蛋白-2，参与了一个通过多细胞区域传递左右线索的信号通路。
