Nuclear Reprogramming - Lecture 20

Question 1

What did Hans Driesch show?

Answer 1

Each cell at the two-cell or four-cell stage are totipotent

Question 2

What did Hans Spemann show?

Answer 2

○ 16 cell stage nuclei remain totipotent
○ Gave rise to clones by migrating the nucleus

Question 3

What did Briggs and Kings do?

Answer 3

Clone frog embryos from blastula stage nuclei but failed to get proper development from nuclei from differentiated cells

Question 4

What does the Waddington landscape show?

Answer 4

Potency decrease with time

Question 5

What did John Gurdon do?

Answer 5

○ Cultured adult skin cells and tadpole gut epithelial cells and removed the nucleus
○ Destroyed the DNA in nucleus of an unfertilised egg
○ Transferred nucleus into egg
- Results: Tadpole develops and that differentiated cells contain all the genes necessary for becoming an adult organism

Question 6

How did John Gurdon produce clones?

Answer 6

○ Removed several nuclei from blastula
○ Implanted nuclei into enucleated eggs

Question 7

What did Keith Campbell and Ian Wilmut do?

Answer 7

Cloned a mammal (Dolly the sheep)

Question 8

What is the structure of the early mammalian embryo?

Answer 8

○ Trophoblast: becomes the placenta and extraembryonic membranes
○ Inner cell mass: forms embryonic stem cells and germ cells
○ Blastocyst cavity
○ Primitive endoderm

Question 9

What can embryonic stem cells be used for?

Answer 9

○ Study development in vitro
○ Generate genetically modified animals
○ Generate teratomas (benign cancers)

Question 10

What did Yoshiki Sasai do?

Answer 10

○ Developed eyes in a test tube and parts of the brain in 3D culture
○ New field: organoids (organs in vitro)

Question 11

What did Shinya Yamanaka do?

Answer 11

○ Reprogramming differentiated cells back to a pluripotent embryonic state without having to use nuclear transplantation
○ Induced pluripotency stem cells (iPS)