6M: Fundamental Development Process Flashcards
MOA of trans-retinoic acid and arsenic trioxide treatment of APL
Trans-retinoic acid (Vesanoid): binds and activates retinoic acid receptors
- changes gene expression and cell differentiation
- decreases cell proliferation
- inhibits telomerase
Arsenic Trioxide (Trisenox): damages/degrades PML-PARalpha fusion protein
- MOA not completely understood
Side effects of trans-retinoic acid drugs and arsenic trioxide
Trans-retinoic acid (Vesanoid):
- teratogenic and embryotoxic properties
- symptoms similar to Vitamin A toxicity
- retinoic acid syndrome
Arsenic Trioxide (Trisenox):
- nausea, vomiting, fever (>30% of patients)
- APL differentiation syndrome (~25% of patients)
- Key symptom is sudden weight gain
blastula vs. bilaminar embryo
Blastula: inner and outer cell mass
Bilaminar embryo: Outer cell mass and differentiated inner cell mass to the epiblast and hypoblast
Define:
a. period of the ovum
b. embryonic period
c. fetal period
a. period of the ovum: fertilization to implantation. Includes zygote, morula, and blastocyst
b. embryonic period: implantation to the 8th week of gestation. Organogenesis occurs (fundamental structure of organs established.)
c. fetal period: 9th week to birth. Rapid growth of fetus and maturation of organ systems
Sponge cell experiments
took purple and red sponge cells and mixed them up in a disk together.
- clumped together eventually in colonies by color
Mouse and Chick intestinal and retinal cell experiments
mixed mouse intestinal and retinal cells with chick intestinal and retinal cells together.
- eventually they clumped based on cell type, not species (i.e. all intestinal cells together and all retinal cells together)
CAM-1 and fibronectin expression in aggregation and migration
CAM-1: High during aggregation and re-aggregation.
- expressed on cells
Fibronectin: High during migration. Cells are said to move on a “fibronectin-paved” migratory pathway
Classical transplantation experiment
Took a frog egg cell and killed the nucleus with UV radiation. Then, took the nucleus from an intestinal cell of another from species and implanted it in the egg cell. They were able to grow a new tadpole.
In any specific stage of development, only ___ % of genes are active
10%
Restriction and totipotency
Restriction: cells reducing their developmental options as they progress through development
- eventually cells are restricted to a single developmental fate through tissue interactions called induction
- 4-cell stage is the last stage where totipotency exists
Differentiation
Process of restriction and determination result in limiting the portion of the genome expressed by a particular portion of cells.
- Differentiation is the functional expression of that part of the genome available to the cell after restriction and determination
Morphogenesis
Those processes that establish the internal and external arrangement of organs or the whole or part of an embryo.
ex: branching
- proliferate, migrate, aggregate, differentiate
Branching
- FGF10 (branching signal) binds to FGFR2
- t-box genes then regulate FGF10 expression
- portion of non-expression of FGF10 occurs so that chemotaxis and proliferation occurs in epithelium at 2 branch points
Embryonic Induction (primary and secondary)
Induction: process by which one embryonic region (X), interacts with another region (Y) to cause the latter tissue to differentiate in a way it wouldn’t have alone
Primary induction: dorsal mesoderm induces ectoderm to differentiate into neural structures
Secondary induction: known as mesenchymal-epithelial interactions. Proximate tissue interactions at close range.
ex: interaction of tissues developing the optic lens
Reciprocal Induction
Information is transferred from epithelium to mesenchym, back to epithelium.
ex: mesenchyme provides the signal to the epithelium for differentiation
Lung bed epithelium + whatever mesenchyme = epithelia will differentiate to where the mesenchyme come from
