Dll1 and Dll4 function sequentially in the retina and pV2 domain of the spinal cord to regulate neurogenesis and create cell diversity
Signalling mediated by Notch receptors is known to have multiple functions during vertebrate neural development, regulating processes like progenitor differentiation and cell type diversification. Various Notch ligands are expressed in the developing nervous system and their activities might contrib...
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Veröffentlicht in: | Developmental biology 2009-04, Vol.328 (1), p.54-65 |
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Sprache: | eng |
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Zusammenfassung: | Signalling mediated by Notch receptors is known to have multiple functions during vertebrate neural development, regulating processes like progenitor differentiation and cell type diversification. Various Notch ligands are expressed in the developing nervous system and their activities might contribute to this multiplicity of functions. Here, we show that two
Delta-like genes,
Dll1 and
Dll4, are sequentially expressed in differentiating neurons of the embryonic mouse retina and spinal cord's pV2 domain, with
Dll1 starting to be expressed before
Dll4. Analysis of
Dll1 mutants reveals this gene is necessary and sufficient to maintain a pool of progenitors in the embryonic neuroepithelium. Accordingly, in the spinal cord domains where Dll1 is the only expressed Notch ligand, its inactivation leads to an increased rate of neurogenesis and premature differentiation of neural progenitors. In contrast, in the pV2 domain and retina where
Dll1 is co-expressed with
Dll4, progenitors are not exhausted and cell diversity is maintained. Together, our results support a model where
Dll1 and
Dll4 are part of a unique genetic circuitry that regulates subsequent steps of neurogenesis in the retina and pV2 domain: while
Dll1 serves to prevent the untimely differentiation of neural progenitors,
Dll4 might function to generate diversity within the population of differentiating neurons. |
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ISSN: | 0012-1606 1095-564X |
DOI: | 10.1016/j.ydbio.2009.01.011 |