P2Y receptors belong to the family of G protein-coupled receptors and are activated by nucleotides in the extracellular space. We showed that Xenopus P2Y1 and P2Y11 were expressed in the dorsal marginal zone from earl...P2Y receptors belong to the family of G protein-coupled receptors and are activated by nucleotides in the extracellular space. We showed that Xenopus P2Y1 and P2Y11 were expressed in the dorsal marginal zone from early gastrula stage and enriched in the central nervous system from neurula stages. They were expressed in the prospective head region during early development. Knockdown of P2Y1 and P2Y11 caused head malformation, such as small eyes, brain atrophy, and defect in cartilage tissues, as well as reduced expression of neural, placode, and neural crest markers. Furthermore, the expression of neural plate and epidermal markers was affected by P2Y1 or P2Y11 depletion at early neurula stage, suggesting that P2Y1 or P2Y11 might be required for the neural induction. Our findings suggested that P2Y receptors might be involved in distinguishing between neural and non-neural fates. The results also suggested that P2Y1 or P2Y11 could play a role in neural induction and/or maintenance of neural tissues in the head formation processes.展开更多
Animal pole cells (AC) and vegetal pole cells (VC) dissociated from early Xenopus gastrulae were intermingled, and the cell sorting process occurring within the aggregate was analyzed. The overall process of cell sort...Animal pole cells (AC) and vegetal pole cells (VC) dissociated from early Xenopus gastrulae were intermingled, and the cell sorting process occurring within the aggregate was analyzed. The overall process of cell sorting was found to morphologically consist of two steps, “concentrification” and “polarization”, as designated here. First, AC and VC clusters emerged at random positions in the aggregate, and the individual clusters gradually assembled themselves by 5 hours in culture (5 hC), forming a concentric arrangement, in which the AC cluster was enveloped by the VC cluster. This concentrification step is essentially consistent with the descriptions in earlier studies. As the next step, the AC and VC clusters moved up and down from 7.5 to 12 hC, resulting in the vertical polarization, namely, a serial array just like in vivo. Immunohistochemical analyses showed that AC expressed both C- and E-cadherins, while VC only expressed C-cadherin, as in vivo, suggesting the normal participation of cadherin system. On the other hand, the actin localization showed that the actin bundles accumulated at the edge of the AC cluster until the concentrification was completed, and gradually decreased during the polarization step. Another important finding was that AC cluster could generate cartilage tissues during the long-term (7 days) culture, evidence for a healthy inductive interaction between the AC and VC. Taken together, the present experimental system allows the AC and VC to be viable and grow into an embryo-like organization.展开更多
文摘P2Y receptors belong to the family of G protein-coupled receptors and are activated by nucleotides in the extracellular space. We showed that Xenopus P2Y1 and P2Y11 were expressed in the dorsal marginal zone from early gastrula stage and enriched in the central nervous system from neurula stages. They were expressed in the prospective head region during early development. Knockdown of P2Y1 and P2Y11 caused head malformation, such as small eyes, brain atrophy, and defect in cartilage tissues, as well as reduced expression of neural, placode, and neural crest markers. Furthermore, the expression of neural plate and epidermal markers was affected by P2Y1 or P2Y11 depletion at early neurula stage, suggesting that P2Y1 or P2Y11 might be required for the neural induction. Our findings suggested that P2Y receptors might be involved in distinguishing between neural and non-neural fates. The results also suggested that P2Y1 or P2Y11 could play a role in neural induction and/or maintenance of neural tissues in the head formation processes.
文摘Animal pole cells (AC) and vegetal pole cells (VC) dissociated from early Xenopus gastrulae were intermingled, and the cell sorting process occurring within the aggregate was analyzed. The overall process of cell sorting was found to morphologically consist of two steps, “concentrification” and “polarization”, as designated here. First, AC and VC clusters emerged at random positions in the aggregate, and the individual clusters gradually assembled themselves by 5 hours in culture (5 hC), forming a concentric arrangement, in which the AC cluster was enveloped by the VC cluster. This concentrification step is essentially consistent with the descriptions in earlier studies. As the next step, the AC and VC clusters moved up and down from 7.5 to 12 hC, resulting in the vertical polarization, namely, a serial array just like in vivo. Immunohistochemical analyses showed that AC expressed both C- and E-cadherins, while VC only expressed C-cadherin, as in vivo, suggesting the normal participation of cadherin system. On the other hand, the actin localization showed that the actin bundles accumulated at the edge of the AC cluster until the concentrification was completed, and gradually decreased during the polarization step. Another important finding was that AC cluster could generate cartilage tissues during the long-term (7 days) culture, evidence for a healthy inductive interaction between the AC and VC. Taken together, the present experimental system allows the AC and VC to be viable and grow into an embryo-like organization.
