Abstract
The NEUROGENINS (NGNs) are neural-specific basic helix-loop-helix (bHLH) transcription factors. Mouse embryos lacking ngn1 fail to generate the proximal subset of cranial sensory neurons. ngn1 is required for the activation of a cascade of downstream bHLH factors, including NeuroD, MATH3, and NSCL1. ngn1 is expressed by placodal ectodermal cells and acts prior to neuroblast delamination. Moreover, NGN1 positively regulates the Delta homolog DLL1 and can be negatively regulated by Notch signaling. Thus, ngn1 functions similarly to the proneural genes in Drosophila. However, the initial pattern of ngn1 expression appears to be Notch independent. Taken together with the fact that ectopic ngn1 expression can convert ectodermal cells to neurons in Xenopus (Ma et al., 1996), these data and those of Fode et al. (1998 [this issue of Neuron]) identify ngns as vertebrate neuronal determination genes, analogous to myoD and myf5 in myogenesis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Basic Helix-Loop-Helix Transcription Factors
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Chimera
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Female
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Gene Expression Regulation, Developmental / physiology
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Helix-Loop-Helix Motifs / physiology
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Male
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Membrane Proteins / physiology
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Mice
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Mice, Inbred C57BL
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Mice, Mutant Strains
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Mutagenesis / physiology
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Nerve Tissue Proteins / genetics*
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Nerve Tissue Proteins / metabolism
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Neural Crest / cytology
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Neurons, Afferent / chemistry*
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Neurons, Afferent / physiology
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Pregnancy
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RNA, Messenger / analysis
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Receptors, Cell Surface / physiology
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Receptors, Notch
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Signal Transduction / physiology
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Stem Cells / chemistry*
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Stem Cells / physiology
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Transcription Factors*
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Trigeminal Ganglion / cytology*
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Trigeminal Ganglion / embryology
Substances
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Basic Helix-Loop-Helix Transcription Factors
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Membrane Proteins
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Nerve Tissue Proteins
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RNA, Messenger
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Receptors, Cell Surface
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Receptors, Notch
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Transcription Factors
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Neurog1 protein, mouse