Neural Tube Dorsal-Ventral Patterning Flashcards
Differentiate between dorsal and ventral sides of an animla.
Dorsal = spinal side
Ventral = belly side
Why is point of sperm entry into a frog egg important?
It influences dorsal-ventral polarity.
Describe how dorsal-ventral polarity is influenced by sperm entry in the frog egg.
Point of entry = dorsal side of embryo
Side 180 deg opposite to entry = ventral side
Outline the dorsal-ventral patterning of the spinal cord.
6
Roof plate
Sensory neurons
Interneurons
Floor Plate
Notochord
What is the ventral pattern of the spinal region imposed by? The dorsal pattern?
Ventral: The notochord
Dorsal: Epidermis
List the two main paracrine factors that specify the dorsal-ventral axis.
Sonic hedgehog protein
TGF-Beta proteins
Where does shh protein originate?
The notochord.
Where do TGF-Beta proteins originate?
From the dorsal ectoderm
What protein is responsible for induction of the floor plate of the neural tube?
Shh
True or false: Floor plate cells also secrete Shh
True
What do floor plate cells experiencing the highest concentrations of Shh develop into?
Progenitor cells for motor neurons and V3 neurons
What do floor plate cells experiencing moderate and lower levels of Shh develop into?
More dorsal progenitor populations.
True or false: Induction of floor plate and affiliated motor neurons requires Shh and another protein.
Flase. Shh alone is sufficient for this induction.
What establishes the dorsal fates of the neural tube?
TGF-Beta proteins
What 4 TGF-B proteins are particularly important in establishing the dorsal fates of the neural tube?
BMP4
BMP7
Dorsalin
Activin
What do cells in the anterior portion of the neural tube become?
Brain and most of spinal cord
List the homeodomain proteins that define six progenitor domains.
6
Pax7
Pax6
Dbx2
Irx3
Nkx6.1
Nkx2.2
True or false: BMPs oppose Shh function.
True
