22. Epigenetics II Flashcards
(16 cards)
What is the role of CDX2 in cell differentiation?
Essential transcription factor for TE formation
Overexpression converts ES cells to TE cells; knockout prevents TE formation and implantation.
Which cells express OCT4?
ICM cells
OCT4 is a stem cell marker.
What happens in the Inside-Out Model regarding cell differentiation?
Outer cells have reduced cell-cell contacts leading to inactive Hippo pathway and activated CDX2
YAP translocates to nucleus and activates CDX2.
In the Cell Polarity Model, what is the effect of Angiomotin (AMOT)?
Prevents AMOT from activating LATS kinases in outer cells
This keeps the Hippo pathway off, allowing YAP to enter the nucleus.
What occurs during DNA methylation dynamics after fertilization?
Paternal genome rapidly demethylated; maternal genome demethylated more slowly
By the 2-cell stage, very low methylation levels are present throughout the genome.
What is the function of OCT4 in pluripotency maintenance?
Activates self-renewal genes and represses developmental control genes
Works with NANOG and SOX2.
What are bivalent domains in the context of gene expression?
Genes are OFF but poised for activation
Characterized by simultaneous presence of repressive and active histone marks.
What is the role of DNMT3A/3B and DNMT1 in epigenetic changes?
DNMT3A/3B are involved in de novo methylation; DNMT1 is involved in maintenance methylation
These enzymes regulate tissue-specific remethylation after global demethylation.
What are the implications of in vitro culture on the epigenome?
Culture conditions can alter epigenetic patterns
Relevant to assisted reproductive technologies (IVF) and associated imprinting disorders.
How does maternal smoking affect DNA methylation in newborns?
Alters DNA methylation in specific genes
Some changes may resolve over time, while others can persist for at least 20 years.
What dramatic example illustrates nutritional effects on epigenetics?
Bees and royal jelly
Royal jelly leads to low DNA methylation and queen bee development.
What were the effects of the Dutch Hunger Winter on offspring?
Increased obesity, cardiovascular disease, and type 2 diabetes linked to altered DNA methylation
Effects can persist for over 65 years.
What is the effect of paternal high-fat diet on offspring?
Influences glucose tolerance in offspring
Mechanism involves small non-coding RNAs in sperm.
What is the significance of the first 1000 days of life in epigenetic programming?
Critical for epigenetic changes linked to disease susceptibility
Emphasis on preconception health and early interventions.
True or False: Epigenetic changes can represent normal adaptation to the environment.
True
They allow flexibility without changing DNA sequence.
Fill in the blank: The process of progression from totipotency to unipotency is associated with _______.
Epigenetic modifications
These modifications progressively restrict gene expression.
