Lect. 13 - nervous system induction Flashcards Preview

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Flashcards in Lect. 13 - nervous system induction Deck (18):
1

primitive nodes' role in forming notochord

provides source of cells that will form the notochord

2

Describe formation of the notochord

cell precursors migrate anteriorly and then left behind as rodlike aggregation as primitive streak regresses; notochordal cells fuse w/ flanking endodermal cells and from a canal; the cells separate and aggregate to form notochord

3

what is the relationship of Nodal to the establishment of the anteroposterior axis

expression of nodal in post. epiblast and blocking of nodal in anterior epiblast (by lefty 1 and cer 1) results in the establishment of the axis

4

how is wnt3 related to nodal?

Wnt3 induces the expression of nodal

5

what signaling molecules are involved in the inhibition of posterior structures?

cerebrus-like and DKK-1

6

what signaling molecules from the primitive node are involved in neural induction?

noggin and chordin

7

nodal is a signaling molecules produced by the primitive node; what is its role in the induction?

it induces the primitive streak and helps establish left-right symmetry

8

what is the source and role of Cerebrus-like and DKK-1 in development of ant.-post. axis?

anterior visceral endoderm; inhibits development of posterior structures

9

what are the origin and effects of TFs goosecoid and brachyury w/ regard to the early primitive streak?

goosecoid: primitive node -activates chordin and noggin
brachyury: primitive streak - notochord fomation; normal movements of cells through primitive streak

10

what genes are targeted by goosecoid?

chordin and noggin

11

what are the effects of Foxa-2 on the early primitive streak stage?

establishment of the primitive node; initiates notochord function; establishes midline strucutres cranial to node

12

in the late primitive streak stage, what signaling molecules is necessary for normal head fromation?

cerebrus-related 1

13

in the late primitve streak stage, what signaling molecules are needed for neural induction, and what is their origin?

noggin, chordin, and shh; origin: notochord

14

determination

a process by which a cell or part of an embryo becomes restricted to a given developmental pathway. The point at which a cell becomes committed to a specific cell line.

15

differentiation:

a complex of changes involved in the progressive specialization of structure and function; often resulting in the formation of luxury molecules

16

what is the first sign of asymmetry in early development?

the beating of cilia around the primitive node which results in a directional current and expression of TGF-beta molecules

17

what role does nodal play in asymmetry?

swept to left side of node; stimulates multiple gene expression pathways via Pitx-2

18

what role does lefty-1 play in asymmetry?

expressed on left side; blocks diffusion of molecules to the right side.