Progenitor cell maintenance requires numb and numblike during mouse neurogenesis.
Neurons in most regions of the mammalian nervous system are generated over an extended period of time during development. Maintaining sufficient numbers of progenitors over the course of neurogenesis is essential to ensure that neural cells are produced in correct numbers and diverse types. The underlying molecular mechanisms, like those governing stem-cell self-renewal in general, remain poorly understood. We report here that mouse numb and numblike (Nbl), two highly conserved homologues of Drosophila numb, play redundant but critical roles in maintaining neural progenitor cells during embryogenesis, by allowing their progenies to choose progenitor over neuronal fates. In Nbl mutant embryos also conditionally mutant for mouse numb in the nervous system, early neurons emerge in the expected spatial and temporal pattern, but at the expense of progenitor cells, leading to a nearly complete depletion of dividing cells shortly after the onset of neurogenesis. Our findings show that a shared molecular mechanism, with mouse Numb and Nbl as key components, governs the self-renewal of all neural progenitor cells, regardless of their lineage or regional identities.
Petersen
Petur H
PH
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.
Zou
Kaiyong
K
Hwang
Joseph K
JK
Jan
Yuh Nung
YN
Zhong
Weimin
W
D000483:Alleles; D000818:Animals; D016923:Cell Death; D002454:Cell Differentiation; D002455:Cell Division; D019070:Cell Lineage; D029721:Drosophila Proteins; D017353:Gene Deletion; D047908:Intracellular Signaling Peptides and Proteins; D007605:Juvenile Hormones / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009046:Motor Neurons / Q000166:cytology* / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009420:Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors
D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007605:Juvenile Hormones; D009419:Nerve Tissue Proteins; C106292:Numbl protein, mouse; C060606:numb protein, Drosophila