... of hindbrain and spinal cord markers in Xenopus embryos. In naïve animal cap explants, XMeis3 activated expression of posterior neural markers in the absence of pan-neural markers. Supporting its role as a neural caudalizer, XMeis3 is expressed in the hindbrain and spinal cord. We show that XMeis3 acts like...

... the caudalizing influence of the organizer. This dual role of the hypoblast is more consistent with the Nieuwkoop model than with the notion of separate organizers, and accommodates the available data from mouse and other vertebrates. Movies available on-line: http://www.biologists.com/Development/movies/dev4408...

...Tuneo Yamada ABSTRACT Caudalization, which is proposed to be one of two functions of the amphibian organizer, initiates posterior pathways of neural development in the dorsalized ectoderm. In the absence of caudalization, dorsalized ectoderm only expresses the most anterior (archencephalic...