Control of gene expression in eukaryotes part 3 Flashcards Preview

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Flashcards in Control of gene expression in eukaryotes part 3 Deck (12)
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1
Q

What five properties define active chromatin

A

i) decondensed structure, absence of histone H1
ii) reduced content in methylated cytosine (5meC)
iii) high proportion of acetylated histones.
iv) Presence of regulatory proteins (mainly activators) bound to their target sites on
the DNA.
v) Increased sensitivity to nucleases

2
Q

What the four different types of alternative splicing

A
  1. optional exon
  2. optional intron
  3. Mutually exclusive exons
  4. Internal splice site (in an intron)
3
Q

Define constitutive splicing

A

Two different splice variants occur from the same strand

4
Q

Define regulated splicing

A

Proteins bind that either facilitate or prevent splicing

5
Q

What is the main factor that causes either a long or short transcript to be generated in the B lymphocyte example?

A

Conecentration of CstF: if lots of it, short transcript is made

6
Q

Define nonsense mRNA degradtion

A

Mechanism that allows the cell to degrade mRNA with a premature stop codon. Makes use of EJCs and UpF proteins to mediate degradation

7
Q

Define upF proteins

A

attracted by ribosome and EJC in context of premature stop codon.

8
Q

Define ADAR

A
  • Adenosine Deaminase Acting on RNA
  • often works near splice sites, changing adenosine to inosine.
  • inosine has similar properties to guanine
9
Q

What are the four types of polarizing distribution?

A

Posterior, anterior, terminal, or dorsoventral

10
Q

What role does the 3” UTR play?

A

This is where transport proteins bind the mRNA

11
Q

What exonuclease shortens Poly-A tails?

A

Deadenylase

12
Q

What role does the 3’UTR play in degradation

A

It has target sequences of endonucleases