These observations suggest that neuroectodermal PCP is not instructed by a preexisting molecular gradient, but induced by a signal from the dorsal blastopore lip. The PCP cue did not depend on the orientation of the graft and was distinct from neural inducers. Tissue transplantations indicated that PCP is triggered in the neural plate by a planar cue from the dorsal blastopore lip. invertebrates develop as protostomes (first mouth) in which the oral end of the animal develops from the first developmental opening, the blastopore. By imaging Vangl2 and Prickle3, we show that PCP is progressively acquired in the neural plate and requires a signal from the posterior region of the embryo. On the outside is the ectoderm, which gives rise to the epidermis (skin and hair) and the nervous system. In normal amphibian development the dorsal ectoderm just above the dorsal lip of the. Cells of the blastopore migrate inward until they reach the opposite side of the blastula, creating an inner tube called the endoderm, which gives rise to the digestive system. During gastrulation, the potencies of ectoderm become limited from general to specific one. Here we investigate the Xenopus neural plate, a tissue that has been previously shown to exhibit PCP. Dorsal Lip of Blastopore and its Significance: The ectoderm in early gastrula remains in an undifferentiated stage, i.e., it has manifold potencies at that stage. Although the segregation of PCP components to opposite cell borders is believed to play a critical role in this pathway, whether PCP derives from egg polarity or preexistent long-range gradient, or forms in response to a localized cue remains a challenging question. deuterostome: noun any of a major division (Deuterostomia) of the animal kingdom that includes the bilaterally symmetrical animals (such as the chordates) with indeterminate cleavage and a mouth that does not arise from the blastopore. At early epiboly stages, we define the blastopore as the endoderm/mesoderm cells themselves, and later as the hole/lumen of the archenteron.
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