Morphogenesis (cleavage and gastrulation) in drosophila III

Question 1

What is the non-muscle myosin?

Answer 1

Myosin II

Question 2

What happens to myosin II in apical constriction following its activation?

Answer 2

It interacts with filamentous actin

Question 3

What does the interaction of MyoII with filamentous actin depend on?

Answer 3

Twist activity

Question 4

What are apical localisation and MyoII activation promoted by?

Answer 4

Fog (folded gastrulation)

Question 5

How does Fog work?

Answer 5

Secreted, then binds to a receptor on the surface of the mesodermal cells

Question 6

How is myoII activated?

Answer 6

Rho ROK kinase system

Question 7

Fog expression for ventral furrow formation?

Answer 7

Initially, low levels anteriorly and posteriorly
Then gets strong along the ventral surface and the posterior midgut primordium

Question 8

Fog expression location following ventral furrow formation?

Answer 8

No more in the ventral surface, now it is in high levels posterialy

Question 9

What regulates the transcription/production of Fog?

Answer 9

Twist

Question 10

What are the GPCRs that Fog binds to?

Answer 10

Smog and Mist

Question 11

What phosphorylates myosin?

Answer 11

Rho kinase

Question 12

What are FGFs?

Answer 12

Fibroblast growth factors

Question 13

How are FGFs involved in mesoderm formation?

Answer 13

They control the spreading of invaginated cells to form the mesodermal layer

Question 14

What are FGF ligands encoded by?

Answer 14

pyramus and thisbe

Question 15

What encodes the FGF receptor?

Answer 15

heartless

Question 16

Where are pyramus and thisbe expressed?

Answer 16

Ectodermal cells

Question 17

Which cells express heartless?

Answer 17

Mesodermal cells

Question 18

What occurs during posterior midgut formation?

Answer 18

Primordial cells undergo apical flattening and constriction
Mediated by actomyosin meshwork that contracts in a Rho-dependent manner

Question 19

What result from posterior midgut formation?

Answer 19

Cup-like structure that moves anterioraly and inside the embryo

Question 20

What is apical constriction in posterior midgut formation induced by?

Answer 20

Fog signalling

Question 21

What makes up the germband?

Answer 21

Mesoderm and ectoderm

Question 22

WHat happens to the mesoderm and ectoderm in germ band extension?

Answer 22

They extend around the posterior tip and end up close to the future head of the embryo

Question 23

Germ band dimension change during germ band extension?

Answer 23

2.5* length, 0.5* width

Question 24

Two phases of germband extension?

Answer 24

Fast, 45 mins–> 60% total extension
Slow, 100 mins

Question 25

Two types of cell rearrangement in germband elongation?

Answer 25

T1 transition, Rosette formation

Question 26

What is planar cell polarity?

Answer 26

Cells are polarized in the plane of the epithelium

Question 27

What is the conventional cell polarity?

Answer 27

Apical basal

Question 28

WHat is planar polarised in the cells undergoing axis elongation?

Answer 28

MyoII

Question 29

Where does Myosin II accumulate when it is under planar cell polarity?

Answer 29

Either side of the cell, and the sides perpendicular to those two don't have any

Question 30

What is rosette formation?

Answer 30

collapse of surfaces of cells--> they form a point that looks like a rosette

Question 31

WHat does rho-kinase block?

Answer 31

Par-3, a regulator of junctional proteins

Question 32

Where are toll 2, 6 and 8 expressed in the embryo?

Answer 32

In stripes along the AP axis

Question 33

What regulates the spatial expression of the toll proteins?

Answer 33

Pair rule genes

Question 34

What controlls the planar polarisation of the cells?

Answer 34

Toll receptors 2, 6, 8

Question 35

Serotonin involvement in the embryo?

Answer 35

Controls axis elongation