M1. development of C. elegans 1

Question 1

hermaphrodite

Answer 1

female (oocytes) and male (sperm) produced -self fertilization

Question 2

larva(e)

Answer 2

hormone-induced larval molts

Question 3

embryo

Answer 3

develop within an egg

Question 4

tool for understanding organ development

Answer 4

c. elegans hermaphrodite

Question 5

sydney brenner

Answer 5

founder of c. elegans genetics

linked genetic analysis to cell division, differentiation and organ development

959 somatic cells

simple gastrointestinal tract and NS

small (~1mm in length) and transparent

Question 6

embryo under goes

Answer 6

cell cleavage : cell division without cell growth

Question 7

john sulston

Answer 7

mapped the cell lineage where every cell division and differentiation could be followed during the development of a tissue

Question 8

cleavage pattern is ..

Answer 8

invariant : the fates of cells are linked to their pattern of division

Question 9

C. elegans is the best studied case of mosaic development:

Answer 9

experiments that destroyed the nuclei of the E cell of the 8 cell stage embryo
-no intestine developed
embryo could not compensate.

Question 10

E cell / intestine is specified by the ______

Answer 10

8-cell stage embryo
-the E cell can be removed from the 8 cell embryo and cultured in isolation
The E cell continues to divide and genes that are normally only express in the intestine are expressed

Question 11

p-granulates

Answer 11

• are cytoplasmic determinants of the germ cells

- cytoplasmic bodies that contain mRNA and proteins required to maintain germ cell fate

Question 12

the first division of the C. elegans fertilized egg is unequal ->

Answer 12

there is a larger AB cell and a smaller P1 cell

Question 13

cytoplasmic determinates

Answer 13

P-granules are asymmetrically localized to the germline at each asymmetric cell division

Question 14

the PAR proteins control

Answer 14

asymmetric cell division
-during the first cell division microtubules emanate from the centrosomes

the egg cortex, the layer of cytoplasm located directly below the cell membrane, is rich in actin microfilaments and microtubule motor proteins

the microtubules not associated with chromosomes interact with the actin cytoskeleton to activate asymmetrical cortex contractions through actomyosin

Question 15

uneven cortical contractions cause..

Answer 15

uneven cortical contractions cause uneven flow of cortical components -> results in expansion of the anterior cortex and the PAR-3/PAR-6/aPKC complex (red)

Question 16

once anterior cortical PAR proteins become localized on one side of the cell

Answer 16

posterior PAR-1 and PAR-2 proteins (blue) can then associate with the posterior cortical

Question 17

kinase

Answer 17

phosphate neg. charge

Question 18

2 distinct domains

Answer 18

a negative feedback loop involving 2 kinases, aPKC, at the anterior, and, PAR-1 at the posterior maintain two distinct domains

Question 19

anterior flow of the cortex causes

Answer 19

posterior-ward flow of the cytoplasmic components (p-granules)

Question 20

partitioning defective

Answer 20

• PAR mutants were identified using a forward genetic screen
• PAR-1 and the PAR-3/PAR-6/aPKC complex are highly conserved in cellular asymmetry (Drosophila oocyte, epithelia, cell movement)