L10-11: Dorsal Closure

Question 1

How does GAL4/UAS technique work?

Answer 1

• Driver lines with GAL4 downstream to some regulatory sequence
• UAS cloned upstream to gene of interest

Question 2

In what stage does dorsal closure usually occur?

Answer 2

stage 13

Question 3

What does dorsal closure hide?

Answer 3

amnioserosa

Question 4

Four steps of dorsal closure

Answer 4

1. Initiation: amnioserosa twitching
2. Epithelial Sweeping
3. Zipping
4. Termination

Question 5

Which junction and which protein is seen in the leading edge during epithelial sweeping?

Answer 5

adherens junction and a-catenin

Question 6

What is the analogy used to describe the epithelial sweeping?

Answer 6

purse string model

Question 7

How is filopodia important in zipping?

Answer 7

When filopodia come into contact, they contract and form adherens junctions to close the gap

Question 8

Where else is filopodia zipping seen?

Answer 8

eyelid closure in mice

Question 9

Dorsal closure requires which 3 genes?

Answer 9

Rac, Rho, Cdc42

Question 10

Does cell division occur to heal wound?

Answer 10

no

Question 11

How does purse string model help wound closure?

Answer 11

apical constriction due to actin contraction through adherens joints reduce the diameter of the wound

Question 12

Rac mutants effect on wound healing?

Answer 12

wound healing is not effected

Question 13

Rho mutants effect on wound healing?

Answer 13

more filopodia and lamillepodia. But no string-purse. This means slower wound healing

Question 14

Cdc42 mutation effects on wound healing?

Answer 14

actin contraction reduces wound diameter in time. But can’t close the wound completely.