Download Development - s3.amazonaws.com

Dr. Gretchen McCaffrey
Molecular Form and Function
• Email: [email protected]
• Office hours:
Wed 2-3pm NS 207
Thurs 12-1pm NS207
Molecular Form and Function
• Introduction to Development
– Eukaryotic Gene Expression
– Cellular Signalling
• Simple Eukaryotic Development: Yeast
• Pattern formation; chick limbs
• Organ identity; floral development
Major points
• The process of plant development occurs in response
to the environment while the process of animal
development is genetically determined
• The process of development is controlled by
sequential changes in gene expression and by cell
signalling
Reading
•
•
•
•
Cpt 21, pp. 388-397
Review Cpt 17, pp. 294-304
Cpt 11, pp. 188-191
Cpt 45, pp. 896-898
Prokaryotic vs. Eukaryotic Gene Expression
17.2
Control of Gene Expression
E. Coli
Human
Eukaryotic Cells
Structure correlates with Function
40.3
Different roles for different
tissues
Adipose
Bone
Muscle
Fat storage
Skeletal support
Contraction/movement
Structure/function determined by differential
gene expression in different tissues
Gene 1:
Gene 2:
Gene 3:
Gene 4:
Encodes RNA Polymerase
Encodes protein that allows formation of fat droplets
Encodes collagen; protein that hardens to form bone
Encodes myosin; protein needed for muscle contraction
_______________________________________________
Adipose cell
Osteoblast (bone forming cell) Muscle cell
17.6
Transcription in eukaryotic
cells requires
transcription factors
=
Regulatory proteins that
binds to DNA and
stimulates transcription
of specific genes
17.7
Differential gene expression in different tissues
depends upon different transcription factors
Gene 1:
Gene 2:
Gene 3:
Gene 4:
Encodes RNA Polymerase
Encodes protein that allows formation of fat droplets
Encodes collagen; protein that hardens to form bone
Encodes myosin; protein needed for muscle contraction
_____________________________________________
Adipose cell
Osteoblast (bone forming cell) Muscle cell
Who is this animal and what’s
special about her?
Dolly is special because:
She was cloned from an adult differentiated cell
Cloning from adult differentiated plant cells
21.5
Plant vs. Animal Development
Plants
Animals
Plant vs. Animal Development
Plants
Rigid cell walls
Energy from sun
Animals
No cell wall
Moves to find food
Development:
Responds to environment/
Body plan formed early/
opportunistic
genetically determined
Single fertilized egg
differentiated tissues ?
21.2
Animal Cells
Fertilized Egg
Determined Cells
Differentiated Cells
Animal Development
• Determination
Progressive restriction of developmental potential
causing the possible fate of each cell to become more
limited as the embryo develops
Animal Development
• Determination
Progressive restriction of developmental potential
causing the possible fate of each cell to become more
limited as the embryo develops
• Differentiation
Structural and functional divergence of cells as they
become specialized during a multicellular organism’s
development; dependent on the control of gene
expression
Muscle Cell Development
Precursor cell
Myoblast (muscle stem cell) = determined
Muscle cell = differentiated
Muscle Cell Development
Precursor cell
changes in transcription factors
= changes in gene expression
Myoblast (muscle stem cell) = determined
more changes in transcription factors
= more changes in gene expression
Muscle cell = differentiated
21.8
Sequential changes in transcription
factors
Changes in gene expression
Changes in cell fate
Single fertilized egg
Two different cells
?
Single fertilized egg
Two different cells
?
21.9
• Cytoplasmic determinants
– Substances deposited by the mother in the egg
she produces that regulate the expression of
genes affecting early development of the
embryo
Development from Two Cells
Development controlled by:
• Sequential changes in gene expression
• Cell Signalling
Induction
• Form of cellular signaling during
development
• Ability of one group of embryonic cells to
influence the development of another.
Muscle Cell Development
Precursor cell
changes in transcription factors
= changes in gene expression
Myoblast (muscle stem cell) = determined
more changes in transcription factors
= more changes in gene expression
Muscle cell = differentiated
Muscle cell Development
Precursor cell
Requires growth factors to continue dividing
Myoblast (muscle stem cell) = determined
Cell division stops
Muscle cell = differentiated
No cell division
Cells secrete signals that target
specific local or distant cells
11.3
Chemical signals
bind to cell
surface receptor
or to intracellular
receptor
45.3
Same chemical signal received by
different cells
different responses
45.4
Different chemical signals received by
same cell
different responses
Nerve cell precursor
Steroid hormone
(Determined)
Nerve growth factor
Hormone secreting cell
(Differentiated)
Neuron
How can signals determine the
fate of the cell?
Steroid hormone
binds
Intracellular receptor
causes
Changes in gene expression
Steroid
hormone
45.5
How can signals determine the
fate of the cell?
Steroid hormone
binds
Intracellular receptor
causes
Changes in gene expression
Growth factor
binds
Cell surface receptor
causes
Changes in gene
expression
Growth factor
11.5
Single fertilized egg
Two different cells
Asymmetric
cytoplasmic
determinants lead to
cellular specific
changes in gene
expression
21.9
Development
Maternal cytoplasmic determinants
Asymmetric signalling molecules
Asymmetric transcription factors
Cell specific transcription factors
Cell specific changes in gene expression
Cell fate
Bio 103 home