Fukui Akimasa, Goto Toshiyasu, Kitamoto Junko, Homma Motohiro, Asashima Makoto
Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan.
Biochem Biophys Res Commun. 2007 Mar 9;354(2):472-7. doi: 10.1016/j.bbrc.2007.01.007. Epub 2007 Jan 10.
During frog gastrulation, mesendodermal cells become apposed to the blastocoel roof (BCR) by endoderm rotation, and migrate towards the animal pole. The leading edge of the mesendodermal cells (LEM) contributes to the directional migration of involuting marginal zone (IMZ) cells, but the molecular mechanism of this process is not well understood. Here we show that CXCR4/SDF-1 signaling mediates the directional movement of the LEM in Xenopus embryos. Expression of xCXCR4 was detected in the IMZ, and was complemented by xSDF-1alpha expression in the inner surface of the BCR. Over-expression of xCXCR4 and xSDF-1alpha caused gastrulation defects. An xCXCR4 N-terminus deletion construct and xSDF-1alpha-MO also inhibited gastrulation. Furthermore, explants of LEM migrate towards the dorsal BCR in the presence of xSDF-1alpha, and altered xCXCR4 expression in the LEM inhibited LEM migration. These results suggest that CXCR4/SDF-1 signaling is necessary for the migrations of massive numbers of cells during gastrulation.
在青蛙原肠胚形成过程中，中内胚层细胞通过内胚层旋转与囊胚腔顶壁（BCR）贴附，并向动物极迁移。中内胚层细胞的前缘（LEM）促进内卷边缘区（IMZ）细胞的定向迁移，但这一过程的分子机制尚不清楚。在这里，我们表明CXCR4/SDF-1信号介导非洲爪蟾胚胎中LEM的定向运动。在IMZ中检测到xCXCR4的表达，并且在BCR内表面有xSDF-1α的表达作为补充。xCXCR4和xSDF-1α的过表达导致原肠胚形成缺陷。xCXCR4 N端缺失构建体和xSDF-1α-MO也抑制原肠胚形成。此外，在存在xSDF-1α的情况下，LEM外植体向背侧BCR迁移，并且LEM中xCXCR4表达的改变抑制了LEM迁移。这些结果表明，CXCR4/SDF-1信号对于原肠胚形成过程中大量细胞的迁移是必需的。
