Development of organisms
Biology 122
Genes and Development
Fig. 19.1
Cleavage in a frog embryo
Fig. 19.2
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Adult Cell Cycle
Cell Cycle of Early Frog Blastomere
Mitosis
Active
Cdk / G2
cyclin
M
C
G1
Cdk / G1
cyclin
Cdk /
cyclin
Active
Mitosis
C
M
G2
M
Active
Cyclin
Synthesis
Cdk /
Active S cyclin
S
DNA Synthesis
a.
S
G2
interphase
M
mitosis
C
cytokinesis
Cyclin
Degradation
S
Inactive
S
Cdk
DNA Synthesis
b.
In blastomeres, cyclin mRNA came from unfertilized eggs.
When cyclin protein is degraded, the cell exits mitosis
Fig. 19.3
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nematode Lineage Map
Egg
Egg and
sperm line
Nervous
system
Pharynx
Intestine
Cuticle-making cells Vulva
Gonad
a.
Adult Nematode
Intestine
Gonad
b.
Gonad
Sperm
Egg
Cuticle
Vulva
Lineage map of C. elegans
Nervous system
Pharynx
Fig. 19.4
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Normal
Not Determined
(early development)
Determined
(later development)
No donor
Donor
Tail cells are
transplanted
to head
Tail cells are
transplanted
to head
Recipient
Before Overt
Differentiation
Tail
Head
Recipient
After Overt
Differentiation
Tail cells develop
into head cells in head
Test for determination
Tail cells develop
into tail cells in head
Fig. 19.5
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
MEIOSIS
Sperm
(haploid) n
50 µm
Egg
(haploid) n
Adult tunicate
(diploid) 2n
n
50 µm
2n
Pigment
granules
Embryo
(diploid) 2n
50 µm
Larva
(diploid) 2n
50 µm
a.
b.
b: © J. Richard Whittaker, used by permission
Tunicate development-muscle determination
Fig. 19.6
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sagittal section
1
Longitudinal section
1
2
Anterior
Anterior
Posterior
Dorsal nerve cord (NC)
Specification of
cell fate in tunicates
Notochord (Not)
Ventral endoderm (En)
Longitudinal section
2
Mesenchymal cells (Mes)
Posterior
Tail muscle cells (Mus)
a.
FGF signaling
Anterior
Posterior
32-Cell Stage
b.
64-Cell Stage
c.
Fig. 19.7-1
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
First Step
Second Step
Cell Types
Yes
Yes
No
Mesenchyme
FGF Signal received
No
FGF Signal received
Yes
No
Notochord
Macho-1 inherited?
a.
Cell fate specification in tunicates
Muscle
Nerve cord
Fig. 19.7
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
First Step
Second Step
Cell Types
Yes
Yes
No
Mesenchyme
FGF Signal received
No
FGF Signal received
Yes
No
Notochord
Macho-1 inherited?
Muscle
Nerve cord
a.
No
FGF
FGF
FGF Receptor
FGF Receptor
FGF Receptor
FGF Receptor
Cell
membrane
Cell
membrane
Cell
membrane
Cell
membrane
Ras/MAPK
Pathway
Ras/MAPK
Pathway
T-Ets
Macho-1
T-Ets
Macho-1
P
Ras/MAPK
Pathway
Ras/MAPK
Pathway
T-Ets
T-Ets
No Macho-1
No Macho-1
P
Suppression of muscle
genes and activation
of mesenchyme genes
Mesenchyme
Precursor Cells
b.
No
FGF
FGF
Transcription
of muscle genes
Muscle
Precursor Cells
Transcription
of notochord genes
Notochord
Precursor Cells
Suppression of notochord
genes and activation
of nerve cord genes
Nerve cord
Precursor Cells
Fig. 19.8
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Once sperm cell and egg cell have joined, cell
cleavage produces a blastocyst. The inner cell mass
of the blastocyst develops into the human embryo.
Embryonic stem cell
culture
Inner cell
mass
Egg
Sperm
Blastocyst
Embryo
Embryonic stem cells (ES cells) are
isolated from the inner cell mass
a.
b.
b: © University of Wisconsin-Madison
Isolation of embryonic stem cells
500 µm
Fig. 19.9
Sheep cloning-Dolly
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Preparation
Cell Fusion
Mammary cell is extracted and grown in
Mammary cell is
nutrient-deficient solution that arrests the cell cycle. inserted inside
Nucleus containing covering of egg cell.
Cell Division
Electric shock fuses
cell membranes and
triggers cell division.
Development
Embryo begins to
develop in vitro.
source DNA
Egg cell is extracted.
Nucleus is removed fro
egg cell with a micropipette.
Embryo
© APTV/AP Photo
Implantation
Birth of Clone
Embryo is
After a five-month pregnancy, a
implanted into lamb genetically identical to the
surrogate sheep from which the mammary
mother .
cell was extracted is born.
Growth to Adulthood
Fig. 19.10
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Oocyte
Nuclear
Transfer
Somatic cells
Reprogramming
Adult cell nuclei
Somatic cells
Fusion
Blastocyst
ES cells
Defined
factors
Culture
Pluripotent
stem cells
Somatic cells
Germ cells
Some adult stem cells
Fig. 19.11
Potential therapeutic cloning of cells for therapy in humans
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
The nucleus from a skin cell of a diabetic patient is
removed.
The skin cell
nucleus is inserted
into the enucleated
human egg cell.
Cell cleavage
occurs as the
embryo begins to
develop in vitro.
The embryo
reaches the
blastocyst stage.
Therapeutic cloning
Embryonic stem cells
(ES cells) are extracted
and grown in culture.
The stem cells are developed
into healthy pancreatic islet cells
needed by the patient.
The healthy tissue is
injected or transplanted
into the diabetic patient.
Inner cell
mass
Diabetic
patient
Healthy pancreatic islet cells
Early embryo
ES
cells
Blastocyst
Diabetic
patient
Fig. 19.12
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Movement of
maternal mRNA
Follicle
cells
Nurse
cells
Posterior Oocyte
Oocyte/egg
Anterior
Nucleus
Drosophila
(fruit fly)
development
Fertilized egg
a.
Syncytial blastoderm
Nuclei line up along
surface, and
Cellular blastoderm membranes
grow between them
to form a cellular
blastoderm.
Blastoderms
Segmented embryo prior to hatching
b.
Hatching larva
Three larval stages
Larval instars
c.
Metamorphosis
Pupa
d.
Thorax
Head
Abdomen
e.
Adult
Fig. 19.13a
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Establishing the Polarity of the Embryo
Fertilization of the egg
triggers the
production of Bicoid
protein from maternal
RN A in the egg. The
Bicoid protein
diffuses through the
egg, forming a
gradient. This
gradient determines
the polarity of the
embryo, with the head
and thorax developing
in the zone of high
concentration (green
fluorescent dye in
antibodies that bind
bicoid protein allows
visualization of the
gradient).
© Steve Paddock and Sean Carroll
500 µm
Fig. 19.13b
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Setting the Stage for Segmentation
About 21/2 hours after
fertilization, Bicoid
protein turns on a
series of brief signals
from so-called gap
genes. The gap
proteins act to divide
the embryo into large
blocks. In this photo,
fluorescent dyes in
antibodies that bind to
the gap proteins
Krüppel (orange) and
Hunchback (green)
make the blocks
visible; the region of
overlap is yellow.
500 µm
© Jim Langeland, Steve Paddock and Sean Carroll
Fig. 19.13c
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Laying Down the Fundamental Regions
About 0.5 hr later , the
gap genes switch on
the “pair-rule” genes,
which are each
expressed in seven
stripes. This is shown
for the pair-rule gene
hairy . Some pair-rule
genes are only
required for
even-numbered
segments while
others are only
required for odd
numbered segments.
500 µm
© Jim Langeland, Steve Paddock and Sean Carroll
Fig. 19.13d
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Forming the Segments
The final stage of
segmentation occurs
when a “segmentpolarity” gene called
engrailed divides each
of the seven regions
into halves, producing
14 narrow
compartments.
Each compartment
corresponds to one
segment of the future
body . There are three
head segments
(H, bottom right), three
thoracic segments
(T, upper right), and
eight abdominal
segments (A, from top
right to bottom left).
© Jim Langeland, Steve Paddock and Sean Carroll
A
T
H
500 µm
Fig. 19.13
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Establishing the Polarity of the Embryo
Fertilization of the egg
triggers the
production of Bicoid
protein from maternal
RN A in the egg. The
Bicoid protein
diffuses through the
egg, forming a
gradient. This
gradient determines
the polarity of the
embryo, with the head
and thorax developing
in the zone of high
concentration (green
fluorescent dye in
antibodies that bind
bicoid protein allows
visualization of the
gradient).
Setting the Stage for Segmentation
About 21/2 hours after
fertilization, Bicoid
protein turns on a
series of brief signals
from so-called gap
genes. The gap
proteins act to divide
the embryo into large
blocks. In this photo,
fluorescent dyes in
antibodies that bind to
the gap proteins
Krüppel (orange) and
Hunchback (green)
make the blocks
visible; the region of
overlap is yellow.
500 µm
500 µm
Laying Down the Fundamental Regions
About 0.5 hr later , the
gap genes switch on
the “pair-rule” genes,
which are each
expressed in seven
stripes. This is shown
for the pair-rule gene
hairy . Some pair-rule
genes are only
required for
even-numbered
segments while
others are only
required for odd
numbered segments.
500 µm
Forming the Segments
The final stage of
segmentation occurs
when a “segmentpolarity” gene called
engrailed divides each
of the seven regions
into halves, producing
14 narrow
compartments.
Each compartment
corresponds to one
segment of the future
body . There are three
head segments
(H, bottom right), three
thoracic segments
(T, upper right), and
eight abdominal
segments (A, from top
right to bottom left).
A
a: © Steve Paddock and Sean Carroll; b-d: © Jim Langeland, Steve Paddock and Sean Carroll
T
H
500 µm
Fig. 19.14
Anterior-posterior development
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Movement of bicoid mRNA moves
maternal mRNA toward anterior end
Nurse
cells
Nucleus
Follicle
cells
Anterior
Anterior
Posterior
Microtubules nanos mRNA moves
toward posterior end
a.
Posterior
bicoid
mRNA
b.
nanos
mRNA
Fig. 19.15-1
Concentration
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Anterior
a. Oocyte mRNAs
nanos mRNA
hunchback mRNA
bicoid mRNA
caudal mRNA
Posterior
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Concentration
Fig. 19.15-2
nanos mRNA
hunchback mRNA
bicoid mRNA
caudal mRNA
Posterior
Anterior
a. Oocyte mRNAs
Anterior
bicoid mRNA
Bicoid protein
caudal mRNA
Caudal protein
Posterior
nanos mRN A
Nanos protein
hunchback mRNA
b. After fertilization
Hunchback protein
Concentration
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
nanos mRNA
hunchback mRNA
bicoid mRNA
caudal mRNA
Posterior
Anterior
a. Oocyte mRNAs
Anterior
bicoid mRNA
Bicoid protein
caudal mRNA
Caudal protein
Posterior
nanos mRNA
Nanos protein
hunchback mRNA
Hunchback protein
b. After fertilization
Concentration
Fig. 19.15
Nanos protein
Hunchback protein
Bicoid protein
Caudal protein
Anterior
c. Early cleavage embryo proteins
Posterior
Fig. 19.16
Dorsal-ventral
development
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a.
400 µm
b.
400 µm
Dorsal
Wild-type embryo Ventral
c.
dorsal mutant
100 µm
a: © Dr. Daniel St. Johnston/Wellcome Images; b: © Schupbach, T. and van Buskirk, C.;
c: From Roth et al., 1989, courtesy of Siegfried Roth
Fig. 19.17
Fig. 19.18a
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Drosophila HOM Chromosomes
Drosophila HOM genes
Antennapedia complex
Bithorax complex
lab pb Dfd Scr Antp
Ubx abd-A abd-B
Head Thorax
Abdomen
Fruit fly
embryo
Fruit fly
a.
Fig. 19.18
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Drosophila HOM Chromosomes
Drosophila HOM genes
Antennapedia complex
lab pb Dfd Scr Antp
Head Thorax
Mouse Hox Chromosomes
Hox 1
Bithorax complex
Ubx abd-A abd-B
Hox 2
Hox 3
Hox 4
Abdomen
Fruit fly
embryo
Mouse
embryo
Mouse
Fruit fly
a.
b.
SEM of HeLa cell undergoing apoptosis
From ATCC photo contest, 2011
Fig. 19.19
Apoptosis pathway
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Organism
Caenorhabditis elegans
Inhibitor:
CED-9
Activator:
CED-4
Apoptotic
Protease:
CED-3
Mammalian Cell
Inhibitor
Apaf1
Caspase-8 or -9
Apoptosis
Inhibition
Activation
a.
Bcl-2
Apoptosis
b.