Coding 5 Flashcards
What is a stem cell?
A self-renewing stem cells that can make differentiating daughter cells but it has high potency for the cells that it can make
What is symmetrical division?
2 self renewing stem cells or daughter cells that are committed to differentiate and the cytoplasmic material is equally divided
What is asymmetrical division?
When a stem cell and a developmentally committed cell are made
Is there more symmetrical or asymmetrical division?
Symmetrical division
What is a multipotent cell?
These are cells that can generate any germ layer tissue which is multipotent
What is a progenitor cell/transit amplifying cell?
These are cells that are only able to divide a few times
What is a stem cell niche?
This is a microenvironment that controls the cells and its impact on regulation
What are the common attributes in cell niches?
- Extracellular mechanisms
- Intracellular changes in stem cell behavior
What are extracellular methods of regulation?
- Physical mechanism such as structural adhesion factors in the ECM
- Chemical regulation by secreted proteins and progenitor differentiation
What are intracellular methods of regulation?
- Regulation of cytoplasmic determinants
- Transcription regulation
- Epigenetic regulation
What is the inner cell mass?
This is the pluripotent region of an early developing blastocyst
What is a pluripotent cell?
These are cells that can give rise to any cell except totipotent cells
What is a totipotent/intial cell?
These are cells that form 2 separate clusters one located at the most apical (shoot) end or the embryo at the most basal (root) end
How are humans unlike hydra and planaria?
Hydra and planaria can regenerate their limbs and the body
What is a morula?
This is an embryo undergoing cleavage but lacks a cavity
What is the trophectoderm?
Totipotent cells that surround the ICM and it makes the placenta
What is the blastocoel?
It is a fluid-filled cavity that formsW
What is the epiblast?
The ICM cells form the epiblast cells which then make the primitive endoderm between the epiblast and trophectoderm cells
What is the primitive endoderm?
The yolk sac
What is the difference between ICM in vitro and in vivo?
The ICM in vitro can generate all cell types but in vivo the ICM cells can self renew indefinitely
What factors ensure that stem cells are uncommitted?
Oct4, nanog, and sox2
What does Cdx2 do for the trophectoderm?
It is an activator for the outer cells of the morula
What does Cdx2 do for the epiblast?
It is a repressor
How is the asymmtrical cell division correlated with the axis?
Perpendicular positioned asymmetrical division leads to segregated daughter cells inside and outside the embryo
How is the symmtrical cell division correlated with the axis?
Parallel positioned symmetric division leads to duaguter cells with an even distribution of cytoplasmic material
What is the hippo pathway in the trophectoderm cells?
- PAR and aPKC bind to AMOT
- YAP/TAZ are available and translocate to the nucleus
- Cdx2 is expressed
What is the aPKC?
An inhibitor of the AMOT receptor
What is the hippo pathway in the ICM?
- E-cadherins bind to AMOT
- Hippo kinase cascade
- Degradation of LATS 1/2
- LATS 1/5 inhibits YAP/TAZ
- YAP/TAZ inhibits beta catening and BMP
- YAP/TAZ translocates to the nucleus
What happens to OCT4 in the epiblast?
It loses OCT4
What was the dogma about neurogenesis?
That brain development stops after birth
What are neural stem cells?
These are cells that originate from progenitor cells known as radial glial
What are the 2 brain regions with NSCs?
- Ventricular subventricular zone
- Subgranular zone
What are the 4 cell types from V-SVZ?
- Layer of endodymal cells along the ventricular wall adjacent to the cerebrospinal fluid
- Neural stem cells known as B cells
- Transit amplifying C cells
- Migrating neuroblasts
What is a crypt?
It is a base of a villus that is like a steep well-like hole
Where is the intestinal stem cell niche?
At the base of the crypt
Where does cell removal happen?
The villi
Where does cell generation occur?
Crypt
What is the crypt base columner cell?
Proliferating intestinal stem cell at the base of the crypt
What is critical to CBCC?
The delta ligand for the notch pathway
What is a paneth cell?
It is a regulatory cell that leads to stem cell regulation and if deleted it detroys the ability to generate other cells
What is a hematopoietic stem cell?
These are stem cells that can generate any type of blood cell
What are the 2 subpopulation for HSC?
- Divide rapidly
- Divide quiescently
Some stem cells are specific to a single type of tissue while others are more versatile what is the latter called?
Mesenchymal stem cells
What regulates MSCs?
- Paracrine factors
- Extracellular matrix
What are the transcription factors in the ICM doing?
They are preventing the differentiation of cells
What does Sox2 and Oct4 do?
Activate nanog and other TFs that established pluripotency and blocked differentiation
What is c-Myc?
Opens the chromatin and makes it accessible for Sox2, Oct4, and nanog
What is Klf4?
It prevents cell death
What is an organoid?
Pluripotent stem cells that make rudimentary organs
What signals are on or off for a paneth cell?
Wnt on
Notch off
What signals are on or off for an enterocyte cell?
Wnt off
Notch on
What signals are on or off for an goblet cell?
Wnt off
Notch off
What signals are on or off for enteroendocrine cells?
Wnt off
Notch on
What forms when a differentiating daugter cell undergoes a transition?
Forms a transit amplifying or progenitor cell
Did yamanaka alter the stem cell niche?
No
What promotes glial genesis?
BMP
