Belting H G, Shashikant C S, Ruddle F H
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.
J Exp Zool. 1998;282(1-2):196-222.
Hox genes are expressed in dynamic patterns during embryogenesis consistent with their role in axial specifications. To study the distribution of mouse Hoxc8, a homeodomain containing protein, we raised monoclonal antibodies against the least conserved portion of Hoxc8. Using these antibodies, we have examined early and mid-gestation embryos for the distribution of the protein. At the end of gastrulation Hoxc8 is expressed in the caudal portion of the embryo. In the neural tube, an early phase when all cells express Hoxc8 is distinguished from a late phase with predominant expression in differentiating neurons. A comparison of this expression pattern with that of a reporter gene under the control of the early Hoxc8 enhancer demarcates three separate regulatory components: (1) initiation and establishment; (2) maintenance; and (3) downregulation. We propose that Hoxc8 expression during embryogenesis is established in multiple phases. Possible regulatory mechanisms involved in generating such a complex domain of Hox gene expression are discussed.
Hox基因在胚胎发育过程中以动态模式表达，这与其在轴向特化中的作用一致。为了研究含同源结构域蛋白的小鼠Hoxc8的分布，我们制备了针对Hoxc8最不保守部分的单克隆抗体。利用这些抗体，我们检测了妊娠早期和中期胚胎中该蛋白的分布。在原肠胚形成末期，Hoxc8在胚胎的尾部表达。在神经管中，所有细胞都表达Hoxc8的早期阶段与分化神经元中主要表达的晚期阶段是有区别的。将这种表达模式与早期Hoxc8增强子控制下的报告基因的表达模式进行比较，确定了三个独立的调控成分：（1）起始和建立；（2）维持；（3）下调。我们提出，胚胎发育过程中Hoxc8的表达是在多个阶段建立的。文中讨论了产生如此复杂的Hox基因表达区域可能涉及的调控机制。
