1. Final
noon Thursday May 5
I will post answers for any remaining questions ed to me by noon on Tuesday May 3

2. Imprinting results from pre-programmed
differences in DNA methylation of selected genes in the sperm and egg
H19 function?

3. Imprinted genes affect fetal growth
Insulin growth factor Insulin growth factor 2
(Igf2) receptor (Igf2r)
growth
growth

4. What happens if dad’s copy of Igf2 is deleted?
Insulin growth factor Insulin growth factor 2
(Igf2) receptor (Igf2r)
growth
growth

5. copy of Igf2 isn’t imprinted?
What happens if mom’s
copy of Igf2 isn’t imprinted?
Beckwith-Weidemann syndrome
Insulin growth factor Insulin growth factor 2
(Igf2) receptor (Igf2r)
overgrowth
growth

6. What if mom’s copy of Igf2r is deleted?
Insulin growth factor Insulin growth factor 2
(Igf2) receptor (Igf2r)
overgrowth
growth

7. T F A mouse that inherits a mutant maternal copy of Igf2 exhibits fetal undergrowth.
T F A mouse that inherits a mutant Igf2r gene from its mother is born 40% smaller than normal.
T F Maternal imprinting of the human Igf2r gene prevents fetal overgrowth.
T F Maternal imprinting of the human Igf2 gene prevents fetal overgrowth.
T F Mutations in the paternal copy of the mouse Igf2 gene cause mice to be born 40% smaller than normal.

8. Experiment #2
Chromatin transferred from myoblasts can transform untreated fat cells.
Transformation frequency suggests
only one or few of the genes have this ability

9. C3H/10T cells = fibroblast cells (make connective tissue, synthesize the extracellular matrix and collagen)
If treated with azacytadine, C3H/10T cells can be induced to form muscle, fat and cartilage cells.

10. Ultimately a single gene was identified- myoD
-whose expression could convert
any other cell type into muscle cells

12. Getting the terminology down: C. elegans Vulva
Early larval stage
Figure 6.27
Anchor cell (AC)
Gonad
VPCs
P3.p-P8.p are the Vulva Precursor Cells (VPCs) AC
Basement membrane
Gonad
Figures\Chapter06\DevBio7e06191.jpg
Later larval stage
P5.p,P6.p and P7.p lineages make the vulva
P3.p,P4.p and P8.p lineages non-vulval 1° 2° 3°
P6.p
P7.p
P5.p
P3.p
P4.p
P8.p 3°

13. The Ras pathway is abnormally activated in many human tumors
eg: pancreatic cancer, colorectal cancer, lung adenocarcinoma, gall bladder cancer, bile duct cancer and thyroid cancer
Another representation of the RAS pathway
(VPC cells)
LIN-3
signal

14. Inductive and lateral signals induce the vulva
gonad
Anchor cell
VPCs P3 P4 P5 P6 P7 P8
VPCs after induction 3° 2° 1°
Figures\Chapter06\DevBio7e06191.jpg
The primary and secondary cells form the vulva

15. A signal from P6.p actives notch (lin-12) in P5.p and P7.p
Figures\Chapter06\DevBio7e06192.jpg
Figure 6.27

16. The transmembrane receptor is the Lin-12 protein, a receptor protein related to Notch
“ Primary cell”
“ Secondary cells”
Both membrane and receptor are membrane bound!

17. Generation of Different Cell Types From Equivalent Cells in C
Generation of Different Cell Types From Equivalent Cells in C. elegans: Initial specification of the Anchor Cell also requires Notch
The signal:
lag-2 (delta)
The receptor: lin-12 (notch)
Figures\Chapter06\DevBio7e06300.jpg
Figure 6.28

19. If anchor cell signaling is disrupted, all VPCs cells adopt a non-vulva fate
gonad
3° cell
3° cell
3° cell
3° cell
3° cell
3° cell
no vulva