fly axis patterning

Question 1

how do the nurse cells generate the posterior?

Answer 1

the oocyte is pushed to the posterior and the oocytes are positioned at anterior

Question 2

what does the nucleus in the posterior oocyte secrete and what does this do?

Answer 2

it secretes gurken which binds to torpedo in the terminal follicle cells. This results in the terminal follicle cells becoming posterior follicle cells and make a factor that activates PKA

Question 3

what does PKA do after released from posterior follicle cells?

Answer 3

• orientates the cytoskeleton to microtubule + end is posterior

Question 4

how does booked get taken to the anterior?

Answer 4

it binds to dynein and gets taken to the negative side of the microtubule

Question 5

how does oskar get taken to the posterior end?

Answer 5

binds to kinesin and gets taken to the positive end

Question 6

how does the nucleus stimulate dorsal follicle cell formation?

Answer 6

releases gurken which binds to torpedo and inhibits pipe

Question 7

where is pipe expressed?

Answer 7

in the ventral cells

Question 8

what does the activate of pipe in the follicle cells result in?

Answer 8

pipe activates an unknown factor which then activates gd which then activates snake which activates easter then spatzle and then Toll which allows dorsal to enter the nucleus on the ventral side.

Question 9

what is the sequence of events in the space between the ventral follicle cell and the oocyte?

Answer 9

pip activates gd with an unknown factor, this activates snake, then easter, then spatzle, then toll then dorsal enters the nucleus on the ventral side

Question 10

how does oskar work to ensure the nanos is refined to the posterior?

Answer 10

oskar and staufen mRNA is transported to the posterior _ end via kinesin where it becomes tethered to the microfilaments. Staufen allows the translation of the oskar mRNA and then oskar will bind to the nanos mRNA and also dissociate it from smaug.

Question 11

what is oskar necessary and sufficient for?

Answer 11

the formation of the pole cells- ectopic can induce the formation of them and removal causes their removal.

Question 12

what are the main sub genes groups involved in AP segment patterning?

Answer 12

• maternal affect (bicoid, hunchback, caudal and nanos
• gap genes: giant, hunchback, cripple, knife, giant hunchback
• pair rule: ftz and eve
• segment polarity: wingless and engrailed

Question 13

what is the pattern of gap gene expression?

Answer 13

giant hunchback kruppel knife giant hunchback

Question 14

what are the two pair rules?

Answer 14

even skipped and ftz

Question 15

what are the segment polarity genes?

Answer 15

wingless and engrailed

Question 16

where is wingless expressed?

Answer 16

where there is no ftz or eve

Question 17

where is engrailed expressed?

Answer 17

where there is high ftz or eve

Question 18

how go wingless and engrailed support each other?

Answer 18

wingless binds frz, which activates exmapression of shh and engrailed, which binds patched on other cell which activates smoothened and allows wingless expression