Epigenetics

Question 1

A change in phenotype that does not result from a change in the sequence of the gene.

• caused by a mechanism other than mutation
• Change is heritable

Answer 1

Epigenetics

Question 2

Signal received—> chromatin changed without changing DNA sequence
*Not all genes are expressed at any given time

Answer 2

Epigenators

Question 3

The interplay between DNA methylation and histone acetylation, and RNAi to completely repress expression of genes
-CpG island is unmethylated (allows for txn machinery to bind) —–>CpG island methylated (physically blocks txn machinery from binding)

Answer 3

Gene silencing

Question 4

Is reversible, but more permanent than not

-Sometimes methylation recruits histone deacytlases to modify histone tails

Answer 4

Gene Silencing

Question 5

• Done in response to signals not spontaneous
• Big insulator proteins stop processes
• Packing pattern is heritable

Answer 5

Histone Tail Modification

Question 6

• Transfer acetyl groups to histone tails, masking their (+) charges
• Relaxes histone and allows txn machinery to get in

Answer 6

Histone acetyl transferases (HATS)

Question 7

• Recruited by DNA methylation

- Reverses histone acetyl transferase activity

Answer 7

Histone Deactylases

Question 8

Regulatory RNAs control target mRNA degradation
Done by:
microRNA (miRNA)
short-interfering RNA (siRNA)
-Used:
  *during development
  *immune system of cell against viruses

Answer 8

RNA interference (RNAi)

Question 9

Protein that picks up shRNA because it recognizes it

Answer 9

RISC (RNA interference silencing complex)

Question 10

(In nucleus) miRNA—>transcribed—>miRNA transcript—>processed—(outside of nucleus)–>short hairpin RNA (shRNA)—>processed—>RISC picks up shRNA—>binds to target mRNA—–>RISC cuts mRNA—->mRNA degraded by exonuclease activity

Answer 10

Process of RNA interference