Lecture 1: Understanding Embryonic Stem Cells
by Douglas A. Melton, Ph.D.
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Welcome by HHMI President Dr. Thomas Cech
Dr. Douglas Melton in the lab
Introduction to stem cells
Development is growth and differentiation
The variety of cell types in the human body
Animation: Human embryonic development
Germ layer make specific tissues
Animation: Germ layers and cell fate
The pancreas: Structure and function
Function of specific pancreatic cells
Role of the pancreas in diabetes
Progressive development creates specialized cells
Demo: Using a DNA chip to study gene expression
Genes are turned on and off at each step of differentiation
Differentiation is like making life decisions
Cytoplasmic factors affect cell fate
Cell-cell interaction also affects cell fate
Q&A: How many genes are involved in differentation?
Q&A: Does the ectoderm determine pigmentation?
Q&A: Does a cell respond to multiple growth factors?
Q&A: Can you change gene expression to change cell types?
Q&A: Can cells be changed in vitro with chemical factors?
Q&A: Do internal and external factors influence cells simultaneously?
Body maintenance and cell renewal
Different cell types have different renewal rates
Stem cells are responsible for maintenance and repair
Two essential properties of stem cells
Blood stem cells can replenish and differentiate
A single blood stem cell can replenish an entire animal
Some cell types replenish by division, not by stem cells
A pulse-chase experiment on pancreatic cell replacement
New β cells are from division, not stem cells
In type I diabetes, no new β cells can be made
Embryonic stem (ES) cells and their traits
How are ES cells derived?
Animation: ES cell creation
Confirming that ES cells are totipotent
Deriving human ES cells and their potential usefulness
Video: Human ES cells differentiating into heart cells
Q&A: Would transplanted ES cells differentiate properly?
Q&A: What stimulates production of external and internal factors?
Closing remarks by HHMI President Dr. Thomas Cech