Dev Biol 2005 Dec 15;2882:434-47. doi: 10.1016/j.ydbio.2005.09.050.

Noelins modulate the timing of neuronal differentiation during development.

Abstract
Noelins comprise a family of extracellular proteins with proposed roles in neural and neural crest development. Here, we show that a previously uncharacterized family member, Noelin-4, functions to maintain neural precursors in an undifferentiated state and biases ectoderm toward a neural fate. We show that Noelin-4 is induced by the neurogenic genes X-ngnr-1 and XNeuroD. Over-expression of Noelin-4 causes expansion of the neural plate at the expense of neural crest and epidermis. Although there is an apparent increase in the neural precursor pool, no increase was noted in differentiated neurons. Later, derivatives such as the neural tube and retina appear enlarged. We show biochemically that Noelin-4 protein is glycosylated and secreted and that it interacts with Noelin-1, an isoform previously found to promote differentiation in neuralized animal caps. Accordingly, the neural precursor expansion activity of Noelin-4 is reversed by co-expression of Noelin-1. Our finding that Noelin isoforms can bind to and antagonize one another suggests that interacting Noelin isoforms may play a role in regulating timing of differentiation.

PubMed ID: 16289448
Article link: Dev Biol
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: acta4 eef1a2 gal.2 krt12.4 myc ncam1 neurod1 neurog1 neurog2 nog olfm1 olfm2 snai2 sox2 tbx2 tubb2b twist1 vamp2


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