Transcript Gene Expression, Function, and Regulation

Gene Expression, Function,
and Regulation
RS: Maribel Alvarez
April 9, 2011
What do this characters have
in common?
They are mutants
What is a mutant?
An organism whose DNA has been changed. These changes
cause the organism to display new characteristics or traits not
found in wild-type.
Wild-type
(Typical form found
in a population)
Mutant
Scientist make mutant animals to study gene
function and their products
~19,000 genes
40% found in humans
~40,000 genes
Almost all genes are
also found in humans
~14,000 genes
50% found in humans
Gene Expression
Gene Expression
x
x
How is the organism affected by the loss of this
gene/protein? What role does the gene/protein have
in the organism.
• The development and growth of an organism is
greatly dependent on the proper expression of
genes
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Human mutations results in
medical conditions
Aniridia:
Sickle cell
anemia:
Pax6
Hemoglobin
Primordial
Dwarfism:
Androgenic
alopecia (baldness):
PCNT
Androgen
receptor(AR)
How does an organism know when and
where a gene is required to be on?
How does your body know when to turn on Pax 6 to make your
eyes?
How does you body know only to turn on Pax 6 in cell located
forehead and nose?
Why don’t you develop eyes on your arm or legs?
Trancription factors are proteins that bind to regions of DNA
to switch on genes in specific regions at a specific time.
They regulate gene expression.
Organisms need genes expressed in specific cells at the
right time. Gene expression must be regulated for proper
growth and development of organisms
•
All cells have the same genetic information however only
specific genes are turned on or expressed in each cell
type
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Gene expression, function, and regulation
• 1. What would happen
if the neuron specific
gene is not expressed
in cell one?
No neuron
1.
•2.
What would happen
if the neuron specific
gene was expressed
instead of the epithelial
specific gene in cell 2?
The cell that was suppose to be an
epithelial cell would be a neuronal cell.
2.
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Decapentaplegic(Dpp) is a TGF-β ligand (protein) important for
wing growth and development in Drosophila
Dpp expression wing disc
What do you think would happen
to the wing if there is a mutation
that would prevent Dpp
expression (Can not be turned
on)?
Adult wing
What do you think would happen to
the wing if Dpp is suddenly turned
on in cells that usually do not
express or need Dpp for wing
development?
BMP4 is the human homolog of Dpp
Drosophila
Humans
Function
Dpp
BMP4
Both required for the early
differentiation of the
embryo and establishing of
a dorsal-ventral axis
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Fibrodysplasia ossificans
progressiva is a disease due to
high levels of BMP4.
75% of human disease genes are also found
in flies