stem cell research bryan spiegelberg [email protected] bspiegel/ x7651
TRANSCRIPT
True/False
President Bush declared research on embryonic stem cells illegal in the U.S.
True/False
Embryonic stem cell research is not funded by Federal money
True/False
President Bush created new restrictions on the use of Federal funds for embryonic stem cell research.
True/False
The widespread use of stem cells in medical treatments is a long way off.
True/False
The widespread use of embryonic stem cells in medical treatments is a long way off.
True/False
Most major religions officially oppose research on embryonic stem cells.
True/False
It is necessary to destroy an embryo to obtain embryonic stem cells.
True/False
Embryonic stem cell research might lead to human cloning.
“Cloning”
Production of multiple genetically identical organisms
True/False
Routine cloning of organisms is stuff of science fiction.
True/False
OK, but higher organisms can’t be cloned.
Dolly (1996-2003): genetically identical to her adult mother
Since: mice, cats, pigs, cattle, rats…no primates, yet…
True/False
No human clones exist.
True/False
Most Americans support research on embryonic stem cells
ABC News poll:
Legality of stem cell research:
58% pro/30% con
Funding SCR:
60% pro/31% con
International Communications Research (ICR) poll
Support stem cell research if it means an embryo is destroyed?
24% pro/70% con
CYTOPLASM -energy production -biomolecule factories -etc.
NUCLEUS -genetic material: information storage
-info helps define cell’s characteristics shape, rate of growth, etc.
• Nucleus/Genetic information– Link between a cell and its ancestor
Information:
DNA → book
chromosomes → chapters
genes → words
DNA vs. Proteins
• Words → don’t mean much without action
PROTEINS → main actors derived from and taking direction from the DNA
Individuality derives ultimately from the DNA
Cells → Tissues → Organs → Organisms
• ~10-100 trillion (1014) total cells in your average human
• ~200 types of specialized cells
Blood cells Neuron
• Blood cells/neurons, etc. are terminally differentiated (a.k.a. post-mitotic)
– Typically stop dividing/growing• Focus on specialty
– When lost → damage/old age• Often need to be replaced: How?
• “Like” cells dividingOR
• Stem cell progenitors
ADULT StemCells:Why?
STEM CELLUndifferentiated
Cell division
TWO DAUGHTER CELLS Two different fates
1. UNDIFFERENTIATED Self-renewal
2. DIFFERENTIATED Replace lost cell
Stem cells by definition
1. Non-terminally differentiated cell that can give rise to specialized cells
2. Able to divide without limit
3. Self-renewal:
Undergo asymmetric cell division
A: Stem cell
B: Progenitor cell
C: Specialized cell
Single cell → Fertilized egg/zygote
10 trillion adult cells
PROLIFERATION
200 specialized types of cells
SPECIALIZATION
EMBRYONICStem Cells:What? Why?
+
FERTILIZED EGG Is it “human”?
Nervous system
Skincells
Germcells
Placenta
etc.
Founding cell must be a totipotent stem cell
• Totipotent: unlimited potencyAble to generate all cells of the developing organism: placenta, somatic cells, germ line
• Pluripotent: some loss of potencyeg. potential progenitor of somatic cells, germ line, but not the placenta
• Multipotent: limited potencyonly generate related specialized cellseg. hematopoietic stem cells differentiate into red/white blood cells, platelets, etc.
• Unipotent: generate a single type of cell (but still self-renewing)
Development
ZYGOTE
MORULA
BLASTOCYST(internal cavity)
2-3 days in mice
Blastocyst
INNER CELL MASS toti/pluripotent
TROPHECTODERM placenta
UTERINE WALL mom
BLASTOCOEL
Inner cell mass: highly potent
• Formation of a teratoma upon injection
– “monster tumor”
– disorganized differentiation upon implantation• Skin, bones, glandular tissues, hair, etc.