Transcript Chapter 14- Mesoderm-paraxial and intermediate

Chapter 14- Mesoderm-paraxial
and intermediate
Fig. 14.1- mesoderm lineages
Recall lineages:
Notochord
3. ________
1. ______
Fig. 12.4
Head
Somites
Cartilage,
skeletal,
dermis
2. __________
Kidney,
gonads
24hr
48hr
Fig. 14.2- mesoderm
lineages in chick
Circulatory,
Body cavity,
extraembryonic
Chapter 14- Mesoderm-paraxial
and intermediate
1. Paraxial mesoderm
Fig. 14.3
1. Paraxial
Neural tube
a. 4 components of somite formation
1. __________________• somites form from ____________
in regular intervals
Head
Somites
Cartilage,
skeletal,
dermis
• total number of somites is __ in chicks, __ in mice
Mechanism? Involves the _______ gene
_____ gene expression correlates with positioning of somites
•This effect is _____________ of all surrounding tissue
2. __________________- mesenchyme is converted to
epithelium prior to final somite formation
• EM proteins fibronectin and N-cadherin link cells into clustered units
1. Paraxial mesoderm
4 components of somite formation (cont.)
3. ___________________________
•Distinct somites give rise to distinct __________
•Specific ___ gene expression predicts the
type of vertebra formed
Somites
hox5
hox6
hox9
hox10
Fig. 11.40-Mouse somites mapped to vertebrate regions and
to specific_____ gene expression
Paraxial
Head
Somite
Cartilage,
skeletal,
dermis
1. Paraxial mesoderm (cont.)
4 components of somite formation (cont.)
4. _____________________- somites form
1) cartilage of ____________ and ribs
2) ___________ of rib cage, limbs and back
3) dermis of the dorsal _________
Paraxial
Head
Somite
Cartilage,
skeletal,
dermis
Sclerotome
cells
Fig. 14.7
Some somite cells become mesenchymal cells again to form
___________________- these will become _____________ of
vertebrae and ribs
1. Paraxial mesoderm (cont.)
4 components of somite formation
4. Differentiation- (continued)
Somites have three ________________ regions
that follow distinct fates:
b. ______ muscles
a. _______
Paraxial
Head
Somite
Cartilage,
skeletal,
dermis
A
c. Body wall
__________
Fig. 14.9
Sclerotome
B
What proteins are involved??
A ___________ produces NT-3 and ____ proteins that influence somite cell
fate
B ____________ produces ___________________ to influence
sclerotome fate
Myogenesis
What dictates the muscle phenotype?
______ is a transcription factor that activates transcription
factors Myf5 and MyoD
Wnt?
Pax3
Myf5 + MyoD
MyoD binding site
Muscle-specific genes
Signaling pathway to activate muscle-specific genes
(Figure not in text)
Introduction of ______ into other cell types converts them to ______
Myoblasts fuse to form ___________ to produce muscle ______
Fig. 14.10
Osteogenesis (Bone development)
What dictates the bone development?
There are three lineages that produce bone1) ________ (vertebrae/ribs)
2) ________________ (limbs)- Not yet discussed
3) Cranial _____________ (head/face)
Osteogenesis occurs by two mechanisms
1) _______________ossification- bone without cartilage precursor
2) _________________ ossification- cartilage converted to bone
1. Intramembrane ossification
Mesenchyme
___________cells
Differentiate into
__________ (bone cell)
Cell _____________
Differentiate into _________
(secrete collogenproteoglycan matrix)
1. Intramembrane ossification (cont.)
Mechanism of ___________________ ossification)
Transcription factor ________ plays a key role
BMP proteins also are important
Mesenchyme
WT
_______
CFB1A -/-
Differentiate into osteoblast
Activates expression of several
_________________ genes
________ KO- all
ossification prevented
Blue- cartilage
Red- Bone
Fig. 14.12
Human disease- _____________________
(CCD)- due to mutations in the ______ gene
2. Endochondral ossification
A
Pax B
Mesenchyme
_______
C
E
D
Proliferation
ceases, ______
is modified
__________
invade,
Chondocytes die
A
B
C
D
Fig. 14.13
Differentiate into__________
Proliferate and form _____ of bone
by producing an EM
F
Adjacent cells
(not
chondrocytes)
differentiate
into __________
to fill in bone
E
F
______________ - cells which hollow out bones to form cavities
• Osteoclasts enter through _____________
• Osteoclasts are likely form blood-lineage ____________
The disease ___________ occurs if too ______ osteoclast
activity- bones become brittle
The disease ___________ occurs if too ___________
osteoclast activity- bones are not hollowed out enough
Intermediate Mesoderm
Fig. 14.1- mesoderm lineages
Recall lineages
Intermediate
Fig. 12.4
Kidney development
Three stages
Kidney,
gonads
Paraxial
Lateral
Circulatory,
Head Somite
Body cavity,
extraembryonic
Cartilage,
skeletal,
dermis
Kidney development
Three stages
1. ________________ arises from
intermediate mesoderm just ventral to
anterior somites and migrates toward tail
2. _________________ cells induce
mesenchyme to form
______________(tubules)
Pronephros
Nephric
Duct
3. Pronephric tubules degenerate, but a
new set of _____________ tubules are
formed (approx 30 in humans) further
down
Fig. 14.18
Kidney development
Three stages
Pronephros
Stage 3. (cont.)
The ________________produces:
a. ______________ stem cells
b. __________ carrying tubes (In
some mammals)
The ______________tubules are formed
from mesenchyme, which induces
____________ buds (these become
ureters that transport urine from
_______________)
Nephric
Duct
Fig. 14.18
Ureteric bud and metanephrogenic mesenchyme interact
to become the kidney- called _______________________
Mechanism of ______________________
1. __________________
mesenchyme (MM)
formed
2. MM secretes GDNF and ____ to induce
___________________ formation
Fig. 14.19
3. Ureteric bud secretes ____ and
_____ to prevent _________ of MM
4. Ureteric bud secretes _____ to
induce mesenchyme cells to
aggregate and become
___________
5. MM induces __________ of
ureteric bud
6. _______________ and growth of the
ureteric bud.