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

What five properties define active chromatin

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

What the four different types of alternative splicing

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

3

Define constitutive splicing

Two different splice variants occur from the same strand

4

Define regulated splicing

Proteins bind that either facilitate or prevent splicing

5

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

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

6

Define nonsense mRNA degradtion

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

7

Define upF proteins

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

8

Define ADAR

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

9

What are the four types of polarizing distribution?

Posterior, anterior, terminal, or dorsoventral

10

What role does the 3" UTR play?

This is where transport proteins bind the mRNA

11

What exonuclease shortens Poly-A tails?

Deadenylase

12

What role does the 3'UTR play in degradation

It has target sequences of endonucleases