veterbrate 3 - CNS Posistion and Cell fate

• How can the domains are distinguished in the neurodevelopment

  The domains of the proliferating epitheliumare distinguished by the expression of different transcription factors.
• How can the DV position affect on neural cell

  Different neuronal cell types develop according to their DV position
• What is essential for DV organisation

  DV organisation requires the notocord
• What happens when notochord is ablation


  leading to loss of floor plate and motor neurons and dorsal markers extend ventrally
• What is the form of notochord

  the cells extends from the dorsal to ventral side, the end of the last cells to migrate through the street? don't migrate outward and they stop to form notochord
• What is the location of notochord

  - it is below and touching ventral side
• What is notochord induce

  Notochord induce floor plate and Motor neurons
• Can floor plate induce

  Yes, floor plate also induced floor plate and motor neurons
• What does sonic hedgehog do?

  It is signalling proteins- short term is Shh
• What is the SHH pathway?

  - Shh binds to the receptors, and the receptive of Shh is Pathched- it then activate the Smoothened to inhibit the GLI activator to activate the transcription

  
• What is the Zone of polarising activity

  - Shh is secreted in those cells and the gradient of concentration of Shh determined what genes were expressed and thus what is digit look like
• Is Shh a morphorgen

  yes
• What is a morphogen

  a molecule that informs a cell where its position is within an organism, based on the concentration of the morphogen
• Where is Shh secreted


  it is secreted from notochord
• What is red fate in the morphogens

  indicate low concentration of morphogen

  
• What is the white fate

  - When the concentration is higher and reach to the threshold, it will indicate the white fate

  
• What happens when the transcription factors are different in the DV fate

  - Each different transcription factors express different downstream of those different genes
• How many domains

  6 domain
• Where is the strongest Shh will express on the trasncription factor

  - Nkx6.1 and Nkx 2.2
• Which is the transcription has sensitive to Shh

  - NKx6.1 is sensitive to Shh, so it needs less Shh to activate it - Pax 7 is highly sensitive to Shh, less concentration will activate it
• What happens when the gene is in the middle of Pax6 and Nkx2.2

  The border is very tight, so they will inhibit each other so no gene will be expressed

  
• Where does Hox gene involve

  Anterior-posterior ectoderm patterning
• What does Hox gene do

  Hox genes encode transcription factors- Hox genes are homeodomain that interacts with DNA to activate programs of gene expression- To determine identity of cells in each segment including those of NS
• What is essential for AP axis defined

  The A/P axis is defined by domains of Hox gene expression
• What is the focus of the statement "Hindbrain patterning revisited: timing and effects of retinoic acid signaling"?

  The statement suggests a revisit to the process of hindbrain patterning, specifically examining the timing and effects of retinoic acid signaling in this developmental context.
• Where is HOx gene expression withih the developing murine spinal cord


  Hox gene expression within the developing murine spinal cord atembryonic (E) 12.5
• How are Hox genes arranged in terms of shades of grey, with specific reference to Hoxa, Hoxb, Hoxc, and Hoxd genes?

  Hox genes are arranged by shades of grey, with Hoxa genes shown in the darkest shade, followed, respectively, by decreasing shades of grey for Hoxb, Hoxc, and Hoxd genes.

  
• What is the relationship between cell fate and position in 3D axes?

  Cell fate correlates with the position in 3D axes.
• How is position sensed in the context of cell fate determination?

  Position is sensed in relation to diffusible morphogens.
• What triggers differences in the expression of transcription factors in cell fate determination?

  Signals from diffusible morphogens bind to cell receptors (surface for shh, nuclear for RA) to trigger differences in the expression of transcription factors.
• In summary, what dictates the fate of a cell in the context of positional signals and transcription factors

  The fate of a cell depends upon the transcription factors that it expresses, which, in turn, depends upon the position of that cell relative to the source of soluble signals.
• What will become the neural crest


  the border between the neuroectoderm and non-neural ectoderm

  
• What will become neural tube

  Neuroectoderm

  
• What determines which cells will be crest?

  Apposition of neural ectoderm and presumptive epidermis.
• What is an early marker for presumptive neural crest

  Pax7
• What is the stage that neural crest is specified prior to Pax 7

  Neural crest is specified prior to Pax7expression at stage 4+
• How to make the neural ectoderm to produce crest

  Neural ectoderm plus BMP4 or BMP7 also produces crest
• What is the molecule that keep neural epithelium stuck together

  - n-cadherin
• What is the pathway that make the cell not sticking together in the migration of the neural crest

  - Sox 2 will inhibit Snail 2 which leads to Cadherin-6B which affect directly to non-sticking cell
• What is the pathway of migration

  - Before the delamination, the Premigratory neural crest happens, to make delamination and lead to migrate cell