differential gene expression

Question 1

development

Answer 1

• a sequence of changes in gene expression that alter cell behaviors which underlie morphogenesis
  (cascade of gene expression)
• signal transduction

Question 2

signal transduction

Answer 2

• driver of differential gene expression and changes in cell behavior/ morphogenesis

Question 3

differential gene expression

Answer 3

• the mechanism of cell differentiation
• accomplished by multiple layers of regulation (hierarchy of regulation)
• cascades of TF’s = cascades of gene expression (sequential activation of TFs)

Question 4

cell behaviors

Answer 4

• division, apoptosis, shape change, adhesiveness, intercalation, migration, signaling
• shape change

Question 5

changes in cell adhesion

Answer 5

• EMT require a loss of adhesiveness
• cells acquire different types of adhesion, allows to specifically adhere to each other and form tissue

Question 6

EMT are important for

Answer 6

• cancer
• development
• wound healing
• metastasis

Question 7

differential cell affinity

Answer 7

• see figure
• 1 type of adhesion cell + another type –> mix, creates segregation of cell types (inner and outer)

Question 8

cadherins

Answer 8

• large family of membrane proteins
• calcium dependent cell adhesion proteins
• homotypic binding specificity
• involved in morpho-regulatory processes… tissue boundaries, rearrangement, cell differentiation and metastasis

Question 9

intercalation

Answer 9

• cells move in between adjacent cells
• stay epithelial

Question 10

invagination

Answer 10

• infolding of a sheet of cells, indenting(draw)
• CHANGE CELL SHAPE

Question 11

involution

Answer 11

• during gastrulation
• inturning/inward movement of an expanding outer layer
• spreads over internal surface of remaining external cells (draw)

Question 12

epiboly

Answer 12

• over the ball
• growth of epidermal ectoderm to cover surface of embryo during gastrulation

Question 13

delamination

Answer 13

• splitting of one cellular sheet or layer into two parallel layers (draw)

Question 14

ingression

Answer 14

• migration of individual cells from surface layers into interior of embryo (draw)
• LOSS OF ADHESION

Question 15

convergent extension

Answer 15

• elongation of cell layer in one dimension and shortening in another dimension
• CELL SHAPE CHANGE / INTERCALATION
• primitive gut forming

Question 16

migration

Answer 16

• movement of individual cells over a substratum of other cells of extracellular material

Question 17

neurulation

Answer 17

• notochord forms, secretes signals that induce formation of neural tube
• notochord signals inhibit ventralizing BMP signals… allows dorsalization of embryo
• cell shape changes
• cell adhesion changes
• results in differentiation of ectoderm into 3 lineages

Question 18

dorsalizing signals from the notochord

Answer 18

• chordin and noggin, inhibit BMP which is an inhibitor of neural formation