Cell migration

Question 1

describe the front to back polarity of the migrating cell

Answer 1

polarity determined by cytoskeleton
cdc42 + rac activated at front of cell, promoting actin polymerisation
Rho at the back promotes contraction of actinomyosin fibres

Question 2

describe the primordial germ cell migration example in mice

Answer 2

posterior epiblast cells induced to differentiate into primordial germs cells. about 40 are formed
these migrate to genital ridge via gut by chemoattractant protein
by time of arrival divided into 8000 cells

Question 3

explain cell migration in developing limbs

Answer 3

limb bud originates from lateral plate mesoderm
muscle precursors from somites subsequently bind into limb bud
muscle precursors attracted into bud by secretion of hepatocyte growth factor (HGF) which acts via c - met receptor on surface of muscle precursors

Question 4

What do cells migrate through?

Answer 4

An extrallular matrix or tissues

Question 5

How are they guided?

Answer 5

By chemotaxis or inhibitory actions that prevent cells going to an inappropriate site