Furthermore, since PS1 is inactivated only in CNS-derived cells, such as CR neurons, but not in meningeal cells in exons 2 and 3 in a small percentage of germ cells.
The desired genotype was obtained at a ratio (approximately ) much lower than the expected Mendelian ratio (1:4), indicating that the integration site of the exons 2 and 3 as template and T7 and SP6 RNA polymerase, respectively.
Investigators took advantage of this property and designed a clever pulse-chase experiment to investigate whether different cell types exited the cell cycle at characteristic times.
Animals at various stages of development were given a pulse of 3[H]-thymidine (3Hd T).
Equal loading and transfer of protein were confirmed by probing the blots with antibodies for α-spectrin (for Nestin) or α-tubulin (for BLBP).The following day, sections were RNase-treated (10 μg/ml) for 30 min at room temperature and washed in 0.1× SSC at 65°C.Sections were then blocked with 1% blocking reagent in maleic acid buffer (Roche Molecular Biochemicals) and incubated with anti-digoxigenin Fab fragments conjugated to alkaline phosphatase (00; Roche Molecular Biochemicals) overnight at room temperature.They secrete the extracellular glycoprotein Reelin, which provides a guidance signal for migrating cortical neurons towards the pial surface ( Rice and Curran, 2001 ; Tissir and Goffinet, 2003).In the absence of Reelin, later born cortical neurons fail to migrate past the earlier born neurons, resulting in inverted cortical layers ( conditional knockout (c KO) mouse in which PS1 inactivation is restricted to the central nervous system (CNS) to address whether PS1 is required for normal cortical lamination and neuronal migration.