The secreted factor noggin, which is expressed in the organizer, can mimic the dorsalizing signal of the organizer. There is two kinds of evidence that noggin protein can directly induce neural tissue. First, neural tissue is induced in the absence of mesoderm. Second, neural tissue is induced in the gastrula stage ectoderm that has lost competence to form mesoderm. Noggin induces cement glands and anterior brain markers, but not hindbrain or spinal cord markers.
New protein appears to be long-sought neural inducer .
Barinaga, M. Neural induction was discovered more than half a century ago, and biologists have been long searching for the molecular signal that triggers it. Noggin has also been found in the brains of adult rats, raising neuroscientists hopes that this may also have a nervous system function. Researchers found that a protein made from one pool of mRNAs would rescue treated embryos, enabling them to form dorsal structures. This protein was then cloned and named noggin because high doses produce embryos with exceptionally large heads. The Harland team had to show that noggin would induce neural tissue formation in pure ectoderm that had been removed from the embryo.