Neural Development and Differentiation Flashcards
What is an organizer region?
Region that induces development of the nervous system by secreting bone morphogenic protein inhibitors which cause cells in the ectoderm to differentiate into neural tissue instead of epithelial tissue.
What are the three layers of cells in an embryo? What will each eventually become?
Ectoderm: Skin and Nervous System
Mesoderm: Muscles, Vascular System
Endoderm: Gut
Describe the development of the Neural tube:
Portion of ectoderm called neural plate begins to invaginate forming the intermediate “neural groove”. Mesoderm makes way for the invagination by pushing outward. Ends of the invagination join forming a tube (neural tube) flanked by two clumps of mesoderm. A continuous sheet of ectoderm and endoderm enclose these structures.
At early neural development, what are the three divisions of the neural tube? What will each structure differentiate into?
Proencephalon - Telencephalon, Diencephalon
Mesencephalon - Midbrain
Rhombencephalon - Metencephalon, Myelincephalon
Describe how a path of differentiation is effected for cells in the ectoderm:
Neighboring cells in the ectoderm secrete bone morphogenic protein. Other cells which sense this protein become epithelial cells. Any cells which do not sense bone morphogenic protein will differentiate into neural cells.
Give examples of BMP inhibitors:
Noggin, Chordin, Follistatin, Fibroblast Growth Factor (FGF)
What molecule is responsible for establishing the dorsal/ventral gradient during development?
Sonic Hedgehog (SHH)
What protein is needed for body axis patterning, cell fate determination, migration, and proliferation?
Wnt
What transcription factor leads to expression of FGF 8?
engrailed
How does differentiation into dopaminergic neurons arise?
FGF8 (due to presence of engrailed) and Otx2 (due to Wnt inhibitors) cause neurons to become dopaminergic
How does differentiation into serotonergic neurons arise?
FGF8 (due to presence of engrailed) and gbx2 (due to Wnt) cause neurons to become serotonergic.
What genes are important for rostral/caudal patterning in the spinal chord (and digit formation)?
HOX
Where are new neurons generated in the brain?
Ventricular Zone
List differentiation types:
Symmetric: Progenitor cell divides into two more progenitor cells
Terminal: progenitor cell divides into another progenitor and a neuron or glial cell.
How does differentiation of neural precursor cells arise?
neighboring cells express a ligand/receptor pair. Delta is the ligand and notch is the receptor. A discrepancy in the expression of a ligand and receptor develops in each cell, with one eventually expressing more Delta and the other more Notch. The cell expressing more Delta will become a neuron and the cell expressing more Notch will become a support cell.
What molecule signals for neurons to stop migrating during development and leave the radial glia? What cell type is responsible for this signal?
Reelin, secreted by Cajal Rettius neurons.
