Drosophila

Question 1

Maternal genes

Answer 1

Determine A/P before MZT

Question 2

gap genes

Answer 2

Establish basic body plan along the A/P axis. When the genes are mutated, large gaps appear in the segmentation pattern
Some of the first zygotic genes
Encode zinc finger transcription factors

Question 3

Pair rule genes (1/2 degree)

Answer 3

In parasegments - expression domains that is one segment wide but offset
Overlapping gap genes provide initial signal for 1 degree pair-rule genes and those transcribe 2 degree
Mutation delete every other parasegment

Question 4

Segment polarity genes

Answer 4

Operate after cellularization
Maintain the parasegmental boundaries from pair-rule genes
Cell fates established in each parasegment though juxtacrine signaling

Question 5

Homeotic genes

Answer 5

Genes that are regulated by the protein products of the previous genes. Specify the characteristic structures of each segment
Mutation result in the transformation of one segment into another

Question 6

Morphogen gradients

Answer 6

A molecule that elicits different responses (e.g. different cell fates) in a concentration-dependent manner

Question 7

Two sources of hunchback

Answer 7

1. Maternal mRNA
2. zygotic mRNA

Question 8

Axial asymmetries in unfertilized egg

Answer 8

There is a Bicoid gradient in the anterior and a Nos gradient in the posterior that’s deposited by the maternal genes before fertilization

Question 9

Micropyle

Answer 9

The area in the anterior of the egg where the sperm enters

Question 10

Ovariole

Answer 10

Ovarioles are the functional units of the Drosophila ovary. Each ovariole consists of a series of developing egg chambers, with the most mature egg chamber located at the posterior end.

Question 11

Ring canal

Answer 11

As the oocyte progresses through the ovariole, it receives maternal products from nurse cells, which are connected to the oocyte through ring canals.

Question 12

Nurse cells

Answer 12

Provide maternal products to the egg

Question 13

Syncytial blastoderm stage

Answer 13

Stage where there are multiple nuclei in one cytoplasm

Question 14

Cellular blastoderm stage

Answer 14

After cellularization when all the cells have individual cell membrane

Question 15

MBT/MZT

Answer 15

Occurs before segment polarity genes

Question 16

cytoplasmic transplantation experiments

Answer 16

Transplanting bicoid into the middle of the embryo caused head structures to form in mirror
Injecting bcd into the anterior of a bcd mutant causes head structures to form

Question 17

Mechanisms for localizing maternal mRNA

Answer 17

Maternal mRNA is trasported on microtubules by motor proteins based on polarity
Bcd by dynein and Nos by kinesin

Question 18

Roles of 3’UTRs in fly A-P patterning

Answer 18

3’UTRs are important because they allow for the inhibition of genes in certain sides of the cell.
Bicoid binds to caudal 3’UTR and Nos binds to Hb 3’UTR

Question 19

Modular stripe enhancers
- how they were identified
- function

Answer 19

They were identified by Edward B. Lewis
Their function is to alter when, where, and how much protein gets made

Question 20

Hedgehog signaling pathway

Answer 20

Half of the autocatalytic feedback loop
Caused by presence of Hh,
-Patched receptor is internalized and degraded
- Smoothened is trafficked into the membrane
- Ci is released intact, enter nucleus as a transcriptional activator

Question 21

Autocatalytic positive signaling loop

Answer 21

Keeps segment polarity genes on to establish cell fates in each parasegment
-Wnt signaling maintain En
-En activated Hh signaling
-Hh signaling maintains Wg

Question 22

Signaling center

Question 23

The Bx code

Question 24

gof Hox Gene mutations

Answer 24

Gain of function Hox gene mutation lead to anterior segments transforming to more posterior segments

Question 25

lof Hox Gene mutations

Question 26

Conservation of Hox genes

Question 27

Paralog