Theodosiou Nicole A, Tabin Clifford J
Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
Dev Biol. 2005 Mar 15;279(2):481-90. doi: 10.1016/j.ydbio.2004.12.019.
The organs of the digestive tract are specified by coordinated signaling between the endoderm and mesoderm during development. These epithelial-mesenchymal interactions lead to the organ-specific morphogenesis and differentiation of regions along the gut tube. In this paper, we show that in the chick, the SRY-related transcription factor Sox9 is a marker for the posterior gizzard. Viral misexpression of Sox9 in the gizzard mesoderm is sufficient to specify epithelium characteristic of the pyloric sphincter. Sox9 expression is normally limited to the region of the posterior gizzard under the regulation of BMP signaling from the adjacent midgut. Misexpression of an activated form of BMPR1b in the gizzard upregulates Sox9 expression, while the BMP antagonist noggin down-regulates Sox9 expression in the gizzard mesoderm. Previously, Nkx2.5 was identified as a marker for the mesoderm of the pyloric sphincter. As with Sox9, BMP signaling appears to regulate Nkx2.5 and its ability to determine the pyloric epithelium. Despite these similarities, our evidence suggests that Sox9 and Nkx2.5 are regulated independently by BMP signaling, and act coordinately to specify the pyloric sphincter.
在发育过程中，消化道器官是由内胚层和中胚层之间的协调信号所决定的。这些上皮-间充质相互作用导致了沿肠管各区域的器官特异性形态发生和分化。在本文中，我们表明在鸡中，SRY相关转录因子Sox9是鸡胗后部的一个标志物。在鸡胗中胚层中病毒介导的Sox9错误表达足以确定幽门括约肌特有的上皮细胞特征。在来自相邻中肠的BMP信号调控下，Sox9的表达通常局限于鸡胗后部区域。在鸡胗中激活形式的BMPR1b的错误表达会上调Sox9的表达，而BMP拮抗剂头蛋白则下调鸡胗中胚层中Sox9的表达。先前，Nkx2.5被鉴定为幽门括约肌中胚层的一个标志物。与Sox9一样，BMP信号似乎调控Nkx2.5及其决定幽门上皮的能力。尽管存在这些相似之处，但我们的证据表明Sox9和Nkx2.5受BMP信号的独立调控，并协同作用以确定幽门括约肌。
