title: Dynamic expression of Dab2 in the mouse embryonic central nervous system.
abstract: BACKGROUND
  Dab2, one of two mammalian orthologs of Drosophila Disabled, has been shown to be involved in cell positioning and formation of visceral endoderm during mouse embryogenesis, but its role in neuronal development is not yet fully understood. In this report, we have examined the localization of the Dab2 protein in the mouse embryonic central nervous system (CNS) at different developmental stages.
  
  
  RESULTS
  Dab2 protein was transiently expressed in rhombomeres 5 and 6 of the developing hindbrain between E8.5 and E11.5, and in the floor plate of the neural tube from E9.5 to E12.5, following which it was no longer detectable within these regions. Dab2 protein was also identified within circumventricular organs including the choroid plexus, subcommissural organ and pineal gland during their early development. While Dab2 was still strongly expressed in the adult choroid plexus, immunoreactivity within the subcommissural organ and pineal gland was lost after birth. In addition, Dab2 was transiently expressed within a subpopulation of Iba1-positive mononuclear phagocytes (including presumed microglial progenitors) within the neural tube from E10.0 and was lost by E14.5. Dab2 was separately localized to Iba1 positive cells from E9.5 and subsequently to F4/80 positive cells (mature macrophage/myeloid-derived dendritic cells) positioned outside the neural tube from E12.5 onwards, implicating Dab2 expression in early cells of the mononuclear phagocyte lineage. Dab2 did not co-localize with the pan-neuronal marker PGP9.5 at any developmental stage, suggesting that Dab2 positive cells in the developing CNS are unlikely to be differentiating neurons.
  
  
  CONCLUSIONS
  This is the first study to demonstrate the dynamic spatiotemporal expression of Dab2 protein within the CNS during development.
authors.affiliation: Department of Anatomy, Faculty of Medicine, The Chinese University of Hong Kong, PR China. rsaleche@polyu.edu.hk
authors.forename: Kwok-Kuen
authors.initials: KK
authors.lastname: Cheung
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Mok
authors.forename: Payam
authors.initials: P
authors.lastname: Rezaie
authors.forename: Wood Yee
authors.initials: WY
authors.lastname: Chan
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics*; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D001921:Brain / Q000196:embryology*; D004622:Embryo, Mammalian / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D008813:Mice, Inbred ICR; D012157:Mononuclear Phagocyte System / Q000196:embryology; D054259:Neural Tube / Q000196:embryology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; C478773:Dab2 protein, mouse