Ch 16 - Epigenetics Flashcards
(17 cards)
What does Ch 16 focus on?
Epigenetic regulation (more important) RNA modification (less important)
How is it possible to condense 1 meter of DNA into 10 micro meters?
Neutralize (histones) & CONDENSE
Histones compaction of DNA?
- see slide
Difference between Euchromatin & Heterochromatin
Eu = majority chromatin in condensed state during interphase; contains active or potentially active genes
He = highly condensed, are not transcribed; accounts for the dark staining regions seen in interphase chromatins.
What are the 2 types of heterochromatin?
Constitutive: is never converted back into euchromatin (ex: centromeres, telomeres, repetitive sequences)
Facultative: transcriptionally silent but retains the potential to convert to euchromatin (ex: X-chromosome inactivation
What does do Ac & Me stand for?
Acetylation & methylation
What are two ways to establish epigenetic modification?
See figure 16.1
Cis-epigenetic changes are _____ through cell division
maintained
Why do trans-epigenetic changes not hold after cell fusion?
idk - look in the book xD (16.1 -16.3 ish)
Epigenetics and Development
Genomic Imprinting: form of gene regulation in which an offspring expresses the copy of a gene from one parent but not the other. this is done through methylation of one parent’s gene
X-inactivation: occurs in embryogenesis, XIC (X inactivation center) plays a key role. two RNA are involved: Xist & Tsix (look it up details)
Specific Cell Types: changes occur during embryonic development that are remembered during subsequent cell division ( ex: muscle cells don’t divide into brain cells)
T/F: X-inactivation is permanent
not sure. Thought she said it wasn’t permanent, but they she said Barr bodies are permanent so…
What are the two key proteins involved in specific cell types?
TrxG - involved in gene activation
PcG - involved in gene repression
What are the differences between the two polycomb groups (PcG) PRC1 and PRC2?
PRC 1: may inhibit transcription in 3 ways:
- chromatin compaction
- covalent modification of histones
- direct interaction with a transcription factor
something something silencing of genes
See slide, ref number 16-19
Stability of mRNA
see slide 35; post transcriptional level
miRNAs & siRNAs define
microRNAs: encoded mostly by genes in eukaryotic organisms (miRNA genes don’t encode proteins; give give to small RNA molecules)
short-interfering RNAs
What may have the benefit of silencing transposing elements?
miRNA
IRP & IRE
be able to explain what they do
iron regulatory protein
iron something something (see slides)
