Axis Specification and Gastrulation in C. Elegans Flashcards Preview

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Flashcards in Axis Specification and Gastrulation in C. Elegans Deck (22):

C Elegans: Phase 1

P0 [posterior] cell only.


C Elegans: Phase 2

P0 splits into AB and P1


C Elegans: Phase 3

AB splits into ABa and ABp. P1 splits into the P2 and EMS


What does EMS stand for?

Endoderm, Mesoderm


C Elegans: Phase 4

The most important things, is that the EMS splits into the MS and the E, whereas the P2 splits into the C and P3.


What component marks the anterior of the worm cell?

Polar body


Step 1: Which side does the sperm usually enter from?

The anterior of the cell


Where do the P granules localize to once the sperm enters?

the posterior


Step 2: Protein assymtetries-->Group the association of PAR-3&6, PAR-2, MEX-5

PAR-3&6 are part of the anterior cortex, PAR-2 part of the posterior cortex, MEX-5 localizes to the anterior


What causes movement of the cortical domain?

Actin and myosin movement


Step 3: More protein rearrangement

PIE-1 AND SKN-1 only show up in the P1 posterior cell, because MEX-5, which is only in the anterior AB cell degrades any PIE-1 and SKN-1 there.


What does MEX-5 do in regards to PIE-1 and SKN-1

MEX-5 degrades PIE-1 and SKN-1 due to ubiquitin pathways


Step 4: PIE 1 ...

represses SKN-1 activity in P2, but does not destroy it


Step 4: So where does SKN-1 act?

SKN-1 is in the EMS and P2, but it only acts in EMS, because PIE-1 counteracts SKN-1, and PIE-1 is only degraded by MEX-5 which is not in P2.


What does lack of SKN1 create?

It causes "skin in excess", which shows up as lack of the pharynx.


Step 5: In the EMS, what does the presence of SKN-1 create?

It allows the activation of MED proteins that activate transcription of mesodermal and endodermal genes in the MS & E.


Step 6: What is mom-2, and what is mom-5?

Mom 2 is the Wnt, and Mom 5 is the frizzled receptor.


Step 6: How is Wnt signaling used?

P2 sends the Wnt MOM-2 to the neighboring EMS cell causing the close on to turn into endoderm.


What does MOM stand for?

More mesoderm


Which two cells undergo ingression?

Ea and Ep


For Ea and Ep to perform ingression, which two cells cover up the space?

P4 and MS


What is it called when the epidermis undergoes epiboly to cover interior cells?

Ventral enclosure.