Cell Movement

Question 1

Claudins and occludins,

Answer 1

which creates tight junctions between adjacent cells

Question 1

Cadherins,

Answer 1

which create classical adherence junctions to ECM

Question 2

Desmosomes,

Answer 2

which create non-classical adherence junctions via intermediate filaments

Question 3

Connexins –

Answer 3

which create cytoplasmic bridge gap junctions via microfilaments

Question 4

Selectins –

Answer 4

non-classical CAMs which promote homphilic attachment

Question 5

Integrins –

Answer 5

intermediate filament hemidesmosome and actin filament focal adhesions which promote heterophilic attachment at cell matrix junctions

Question 6

Cell rearrangement in Xenopus and Danio

Answer 6

polarised mesenchymal neighbour cells intercalate during convergent extension during and post-gastrulation, to generate force and directionality

Question 7

EMT

Answer 7

mesodermal epiblast cell ingression in avian embryo

Question 8

epithelial morphogenesis

Answer 8

complex epiblast cell movement in the primitive streak region within the epithelial plane

Question 9

mesenchymal morphogenesis

Answer 9

mesenchyme cells migrate away from the primitive streak

Question 10

lateral line cell migration

Answer 10

• primordium = 100s of cranio-ectoderm derived neural cells that undergo AP migration under the skin but above the muscle along the embryo flank facilitated by loose junctional complies at their leading edge undergoing partial EMT, and a chemoattractant trail (sensed only by the leading edge receptors) along the myoseptum

Question 11

NC polarisation

Answer 11

• contact inhibition and C3a attract and receptor co-expression
• preferential fibronectin, laminar and collagen adherence (sensitive to substrate stiffness)

Question 12

Describe gastrulation

Answer 12

1. epithelial bending apical constriction forms bottle cells at the dorsal blastopore tip
2. cell rearrangement drives mesodermal convergent extension and epiboly
3. EMT drives mesodermal ingression
4. Cell migration of the anterior mesoderm across the blastocoel roof

Question 13

Describe neurulation

Answer 13

• epithelial bending drives neural fold formation
• cell rearrangement forms notochord
• EMT drives NC migration

Question 14

Crib

Answer 14

1) CAMs and the dAH
2) epithelia, mesenchyme and the cytoskeleton
3) epithelial bending
4) cell rearrangement
5) epithelial dissociation
6) migration