Summary
Summary H8: mesoderm and neuroectoderm patterning summarizing prof. Zwijsen
- Course
- Institution
summary of the course Concepts of developmental Biology. chapter 8: mesoderm and neuro ectoderm patterning by prof. Zwijsen
[Show more]
Seller
Follow
jokevandevelde03
Content preview
H8: MESODERM ANDNEUROECTODERM PATTERNING
A. ZWIJSEN
Inhoudsopgave
8.1 SPEMANN ORGANIZER (DORSAL BLASTOPORE LIP).............................................2
8.2 MESODERM PATTERNING IN XENOPUS...............................................................3
8.2.1 MARGINAL ZONE................................................................................................................... 4
8.2.2 THE ROLE OF THE ORGANIZER................................................................................................. 5
8.2.3 NOGGIN.............................................................................................................................. 5
8.2.4 BLASTOPORE LIP SECRETES DIFFERENT ANTAGONISTS OF VENTRALIZING FACTORS..............................7
8.2.5 MESODERM PRODUCES IT’S OWN PATTERNING FACTORS................................................................8
8.2.6 HOW TO ORIENT................................................................................................................. 10
8.3 MESODERM PATTERNING IN MOUSE................................................................11
8.3.1 MESODERM CLASSES........................................................................................................... 12
8.4 ECTODERM DEVELOPMENT..............................................................................13
8.4.1 SPEMANN ORGANIZER TRANSPLANTATION.................................................................................13
8.4.2 NEURAL TISSUE IS INDUCED IN ECTODERM OVERLYING THE ORGANIZER..........................................13
8.4.3 ANTAGONISTS SECRETED BY THE ORGANIZER............................................................................14
8.4.4 NEURAL INDUCTION FEATURES............................................................................................... 16
8.4.5 NEURAL PLATE-NEURAL GROOVE-NEURAL TUBE.........................................................................17
8.4.6 CO-LINEARITY (A-P) BETWEEN NEURAL TISSUE AND MESODERM...................................................18
8.4.7 NEURAL TUBE CLOSURE....................................................................................................... 19
8.4.8 NEURAL TUBE DEFECTS........................................................................................................ 19
8.4.9 DORSAL VENTRAL PATTERNING OF THE NEURAL TUBE.................................................................20
8.5 NEURAL CREST CELLS.....................................................................................24
8.5.1 CELL LINEAGE TRACING EXPERIMENTS.....................................................................................25
8.5.2 GENERATION OF A WIDE VARIETY OF CELLS AND TISSUES............................................................26
8.5.3 NEURAL CREST CELLS ARE MULTIPOTENT.................................................................................27
8.5.4 DIFFERENT TYPES OF NEURAL CREST CELLS..............................................................................27
8.5.5 DERIVATIVES OF THE NEURAL CREST LINEAGE...........................................................................28
8.5.6 CRANIAL NEURAL CREST CELL DERIVATIVES..............................................................................28
8.5.7 CARDIAC NEURAL CREST CELL DERIVATIVES..............................................................................29
8.5.8 NEURAL CREST CELLS ARE REPELLED BY EPHRIN PROTEINS IN SOMITES...........................................29
8.5.9 NEURAL CREST CELLS AND EVOLUTION BEAK MORPHOLOGY........................................................30
8.6 NEURAL CREST SYNDROMES...........................................................................30
8.6.1 PIEBALDISM....................................................................................................................... 30
1
, 8.6.2 WAARDENBURG SYNDROME..................................................................................................31
8.6.3 DIGEORGE SYNDROME......................................................................................................... 31
8.6.4 CLEFT LIP/PALATE............................................................................................................... 31
Goals:
Understand concepts of:
o mesoderm induction and mesoderm patterning
o neuroectoderm development and A-P and D-V patterning
o neural crest cell development and plasticity
Understanding organizer concepts and experiments how to prove organizer activity
Understanding different mechanisms how cells can acquire positional identity
Recognizing and localizing different types of mesoderm
Proposal of working hypotheses on patterning and experimental design to test such
hypotheses
Interpretation of (unseen) embryonic patterning phenotypes and congenital defects
Let’s revise:
Patterning
Interpretation of positional information
o Hox-code (class 7)
o French flag (morphogens and threshold levels)
o Extracellular antagonists of morphogens
‘Sorting out of cells’
Lateral inhibition can give a spacing pattern
Patterning:
o Mesoderm
o Neuroectoderm
o Neural crest
Syndroms
EMT:
= Epithelial to mesenchymal transition
Cells will change there polarity and stars to migrate as indivual
cells and will transform in mesenchymal cells.
Cells that once went to the epithelial streak and can undergo a
second or even third wave of EMT
8.1 SPEMANN ORGANIZER (DORSAL
BLASTOPORE LIP)
2
,Cells become dorsal mesoderm: (prechordal plate mesoderm, notochord, paraxial mesoderm
situated beneath dorsal ectoderm (important for neural induction).
Nieuwkoop center is important for the signals for inducing mesoderm
its nodal related (= TGFβ member)
nieuwkoop center is within endoderm (high concentrations of nodal)
Signal in the vegetal side of the embryo that will induce the dorsal blastopore lip,
the cells that induce this are called the Spemann organizer. The mesoderm that is
formed here will become dorsal mesoderm (notochord!)
Dorsal mesoderm very important the for neural induction!
Mesoderm cells will get either identity of
dorsal or ventral ventroderm dependent on
which endoderm is put in the sandwich (die
gele streep denk ik)
What makes that a whole serie of
mesodermal cells can develop?
Experiment:
animal cap cells + dorsal vegetal
cells
⇒ dorsal mesoderm
animal cap cells + ventral vegetal cells
⇒ ventral mesoderm
8.2 MESODERM PATTERNING IN XENOPUS
very comparable to zebrafish
3
, 8.2.1 MARGINAL ZONE
Marginal zone (MZ) = equatorial region (MZ = regionalized)
Animal cap will be hidden behind the screen when we look at it, the dorsal
side is on top and ventral on the bottom. We look at the equatorial region.
zo kijken we naar die cel
Experiment:
In situ hybridization (show-it experiment)
This is not a DNA in situ because if you do that, the DNA is the same over the cells. This
is RNA in situ hybridization because that tells us which and where genes are turned on
and off. This is a ‘show it’ experiment
Make a fate map of the equatorial region/marginal zone
⇒ you find all the types of mesoderm cells. All these markers are expressed in the
mesoderm but not in the same domain. Different regions express different markers
o Some genes specifically expressed in the ventral mesoderm
Xvent-1, Xvent-2, xMyoD (Xvent-2 covers the whole equatorial region)
o Some genes specifically expressed in the dorsal mesoderm
noggin, xMyf-5 (Noggin is always expressed in that one side of the cell.)
DMZ late blastula + VMZ co-explant:
→ DMZ and VMZ regulate patterning in mesoderm
? How !?? Something secreted by DMZ
When you culture a little piece of dorsal mesoderm in combo
with ventral mesoderm than you will obtain in the ventral mesoderm heart cells… Normally it
forms only blood and mesenchyme but now also forms cardiac myocytes and pronephros.
It can be induceed provided that the tissue are in contact with each other
Some signals in the left piece communicate with the cells in the right little piece onstaan
intermedial celtypes
Dorsal and ventral mesoderm talk to each other! And by that conversation the
intermediate region gets specified. But then the question becomes which signals are
being used?
DMZ (dorsal marginal zone, mesoderm) and VMZ (ventral marginal zone,
mesoderm) regulate the patterning in mesoderm!
Found out that the DMZ secretes something that is necessary to induce that
4
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller jokevandevelde03. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.14. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
72799 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now