L5 - Anterior vs Posterior

Question 1

What three systems must be developed

Answer 1

ENS PNS CNS

Question 2

What regions make up the forbrain

Answer 2

Lateral ventricle
Telencephalon 
Neural retina 
Lens
3rd ventricle

Question 3

What regions make up the midbrain

Answer 3

Mesencephalon and the cerebral aqueduct

Question 4

What regions make up the hind brain

Answer 4

Metencephalon
Myclencephalon
4th ventricle

Question 5

What layers lie under the posterior end of the neural plate

Answer 5

Notochord

Question 6

What layers lie under the anterior end of the neural plate

Answer 6

Anterior endoderm

Prechordal mesoderm

Question 7

What can be said about the signals from the anterior endoderm and prechordal mesoderm compared to the notochord, what does this cause

Answer 7

Slightly different signals

Signals from the anterior endoderm and prechordal mesoderm cause the induction of the anterior neural identity

Question 8

What experiemental evidence can be obtained if developement is stopped at the instnant where the prechordal mesoderm has involuted

Answer 8

Look at the molecular markers can see that the neural plate expresses makers which are later confined to the forebrain
i.e. the early neural plate is anterior in character

Question 9

Describe the activation-transformation model and its relevance to the determination of the posterior and anterior identities

Answer 9

Signals from the notochord cause cells at the back end of the neural plate to proliferate
At the same time other signals from the notochord changes these cells from an anterior to posterior identity
Anterior TFs are turned OFF
Posterior TFs turned ON

Question 10

What is the activation-transformation model the basis for

Answer 10

The formation of the anterior forebrain and the posterior hind brain and spinal chord

Question 11

What signals are involved at the anterior end

Answer 11

BMP antagonists and WNT antagonists

Question 12

What signals are involved at the posterior end

Answer 12

FGFs (in a gdt highest most posteriorly)
WNTS (in a gdt highest most posteriorly)
RA (in a gdt highest most posteriorly)

Question 13

Describe how RA (what does it stand for) signalling works

Answer 13

Retanoic acid
Small so able to diffuse into cells where it binds to a cytosolic receptor - complex RA-R able to enter the nucleus where it directly influences gene expression

Question 14

Segmentation occurs as a result of

Answer 14

Step wise difference in the gradients of the signalling moleucles

Question 15

What are the two models for segemetation by a morphogen

Answer 15

Alan Turing - reaction diffusion

Lewis- wolpert Postional infromation (french flag)

Question 16

What does HOX stand for

Answer 16

Homeobox containing

Question 17

Describe what the HOX genes are responsible for

Answer 17

Selection of a certain body area fate along the AP axis e.g. abdomen and the thorax

Question 18

Describe the different genes that are involved in the segmentation of the drosophila

Answer 18

Gap
Pair rule
Homeotic genes
Segment polarity genes

Question 19

What are the different segments of the drosophila

Answer 19

T1-T3 and A1-A8

Question 20

T1-T3 controlled by

Answer 20

UBX

Question 21

A1-A4 controlled by

Answer 21

AbdA

Question 22

A5-A8 controlled by

Answer 22

AbdB

Question 23

What causes activation of the HOX genes

Answer 23

Very specific threshold concentrations of posteriorising factors

Question 24

How many HOX genes in humans

Why is this the case

Answer 24

4

Safety measure incase of mutation

Question 25

What is homeobox DNA

Answer 25

Encodes a DNA binding protein of 60 amino acids called the homeodomain

Question 26

What are the different regions of hind brain and spinal cord defined by

Answer 26

HOX signature

Question 27

What does the RA gradient induce

Answer 27

Different patters of HOX transcript

Question 28

What occurs in a knock out of HOXa1 and HOXb1

Answer 28

These genes are required to specify rhombomeres 4 and 5 and nerves that are normally made in this region
So double knockout for these genes results in a mouse that will develop without the abducens nerve

Question 29

Where are the midbrain strucutres induced

Answer 29

At the interaction between the forebrain and hindbrain boundary

Question 30

What are the three primary brain vesicles

Answer 30

Prosencephalon
Mesencephalon
Rhombencephalon

Question 31

What does the prosencephalon give rise to

Answer 31

Telencephalon

Diencephalon

Question 32

What does the rhombencephalon give rise to

Answer 32

Metencephalon

Mycelnecphalon

Question 33

What does the mesencephalon give rise to

Answer 33

Midbrain

Question 34

What does the telencephalon give rise to

Answer 34

Olfactory bulbs
Hippocampus
Cerebrum `

Question 35

What does the diencephalon give rise to

Answer 35

Retina
Epithalamus
Thalamus
Hypothalamus

Question 36

What does the metencephalon give rise to

Answer 36

Cerebellum

Pons

Question 37

What does the myclencephalon give rise to

Answer 37

Medulla

Question 38

The early ground plan for the mature NS is established by?..

Answer 38

Antagonistic signalling centres