Lecture 13: Nervous System Induction

Question 1

Cerebrus-like and DKK-1

Answer 1

Origin: anterior visceral endoderm
Role: inhibits development of posterior structures and thus establishes the A/P axis

Question 2

What are the effects of Foxa-2 in the early primitive streak stage?

Answer 2

Establishes primitive node, initiates notochord function, establishes midline structures from cranial end to node

Question 3

What signaling molecule is necessary for normal head formation in late primitive streak stage?

Answer 3

Cerebrus-related 1

Question 4

What signaling molecules released from primitive streak activate Hox genes in the late primitive streak stage?

Answer 4

Retinoic acid, Wnt, FGF

Question 5

Determination

Answer 5

Process by which cell/part of embryo becomes restricted to a given developmental pathway (committed to a specific cell line)

Question 6

Differentiation

Answer 6

Complex of changes involved in progressive specialization of structure and function, often resulting information of luxury molecules

Question 7

What is the 1st sign of asymmetry in early development?

Answer 7

Asymmetrical beating of cilia around primitive node resulting in directional current and expression of TGF-B molecules

Question 8

What is the role of Nodal with respect to L/R asymmetry?

Answer 8

Nodal is swept to the left side of the embryo by the ciliary current; stimulates multiple gene expression pathways via Pitx2

Question 9

What is the role of Lefty-1 with respect to L/R asymmetry?

Answer 9

Lefty-1 is expressed on the left side of the embryo and blocks diffusion of genetic material to the right side