Cell Fate and Embryonic Induction

Question 1

Difference between preformation and epigenesis

Answer 1

Correctly position in fertilised egg / added progressively during development

Question 2

Cleavage divisions in ascidians

Answer 2

Holoblastic

Question 3

Yellow cytoplasm of ascidian always found in

Answer 3

Muscle cells of the larval tail

Question 4

macho-1

Answer 4

A putative zinc-finger TF, sufficient and necessary for primary muscle formation

Question 5

Maternal macho-1 is localised in _______ cytoplasm at ___ and ____ cell stage

Answer 5

in yellow cytoplasm at 16 and 32 cell stage

Question 6

Embryonic regulation

Answer 6

Ability of embryo to develop normally when portions are removed or rearranged

Question 7

Embryonic induction

Answer 7

Process whereby cell-cell signalling affects development of responding cells

Question 8

Competence

Answer 8

Ability of cell/tissue to respond to an inductive signal

Question 9

Mesoderm is induced in the ______ fragment by the ______ fragment

Answer 9

animal, vegetal

Question 10

Which proteins are good candidates for mesoderm-inducing signal?

Answer 10

Nodal and GDF3 in TGFb families

Question 11

Xenopus Nodal RNA is localised to _______ hemisphere of _______

Answer 11

Localised to vegetal hemisphere of blastula

Question 12

Inhibition of nodal signalling

Answer 12

Blocks mesoderm formation

Question 13

Nodal induces expression of

Answer 13

TF brachyury and several members of the FGF family

Question 14

STK

Answer 14

Serine/thereonine kinase in cytoplasmic kinase domain of c.s. receptor for TGFb ligand

Question 15

Tyrosine kinase is in the ______ domain of ____ receptor for ____ ligand

Answer 15

In cytoplasmic kinase domain of c.s. receptor for FGF ligand

Question 16

TGFb ligand becomes ______ that binds to extracellular domain of ________

Answer 16

Dimer, type 1 and type 2 receptors

Question 17

Activated type 1 receptors

Answer 17

Phosphorylate smad2

Question 18

Smad 2: Smad 4 complex

Answer 18

Migrates into nucleus where it interacts with co-transcription factors and binds to cis-regulatory elements

Question 19

Why is nodal signalling an auto-regulatory loop?

Answer 19

TGFb + FGF signals positively regulate transcription of brachyury which encodes a T-box transcription that positive regulates fgf4 and fgf8

Question 20

At early stages, neural tube at ventral half divides into:

Answer 20

1. Floor plate cells at ventral midline above notochord
2. Motor neurones
3. Interneurons

Question 21

Shh is both sufficient and necessary for formation of

Answer 21

Ventral neural tube sub-types

Question 22

From low to high concentration of Shh

Answer 22

V0, V1, V2, Motor Neurons, V3 and finally floor plate

Question 23

Shh is a _____, ____ secreted from _____ plate

Answer 23

morphogen -> BMP secreted from roof plate

Question 24

Shh -> mesodermal cell type

Answer 24

Sclerotome

Question 25

Nodal induces _______ when added to _______ caps

Answer 25

Mesoderm, animal