title: Period 2 regulates neural stem/progenitor cell proliferation in the adult hippocampus.
abstract: BACKGROUND
  Newborn granule neurons are generated from proliferating neural stem/progenitor cells and integrated into mature synaptic networks in the adult dentate gyrus of the hippocampus. Since light/dark variations of the mitotic index and DNA synthesis occur in many tissues, we wanted to unravel the role of the clock-controlled Period2 gene (mPer2) in timing cell cycle kinetics and neurogenesis in the adult DG.
  
  
  RESULTS
  In contrast to the suprachiasmatic nucleus, we observed a non-rhythmic constitutive expression of mPER2 in the dentate gyrus. We provide evidence that mPER2 is expressed in proliferating neural stem/progenitor cells (NPCs) and persists in early post-mitotic and mature newborn neurons from the adult DG. In vitro and in vivo analysis of a mouse line mutant in the mPer2 gene (Per2Brdm1), revealed a higher density of dividing NPCs together with an increased number of immature newborn neurons populating the DG. However, we showed that the lack of mPer2 does not change the total amount of mature adult-generated hippocampal neurons, because of a compensatory increase in neuronal cell death.
  
  
  CONCLUSIONS
  Taken together, these data demonstrated a functional link between the constitutive expression of mPER2 and the intrinsic control of neural stem/progenitor cells proliferation, cell death and neurogenesis in the dentate gyrus of adult mice.
authors.affiliation: Developmental Neurobiology Unit, Center for Cellular and Molecular Neurobiology, University of Liège, Liège, Belgium. Laurence.borgs@student.ulg.ac.be
authors.forename: Laurence
authors.initials: L
authors.lastname: Borgs
authors.forename: Pierre
authors.initials: P
authors.lastname: Beukelaers
authors.forename: Renaud
authors.initials: R
authors.lastname: Vandenbosch
authors.forename: Laurent
authors.initials: L
authors.lastname: Nguyen
authors.forename: Gustave
authors.initials: G
authors.lastname: Moonen
authors.forename: Pierre
authors.initials: P
authors.lastname: Maquet
authors.forename: Urs
authors.initials: U
authors.lastname: Albrecht
authors.forename: Shibeshih
authors.initials: S
authors.lastname: Belachew
authors.forename: Brigitte
authors.initials: B
authors.lastname: Malgrange