Flashcards in Control of gene expression in eukaryotes part 3 Deck (12)
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
v) Increased sensitivity to nucleases
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)
Define constitutive splicing
Two different splice variants occur from the same strand
Define regulated splicing
Proteins bind that either facilitate or prevent splicing
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
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
Define upF proteins
attracted by ribosome and EJC in context of premature stop codon.
- Adenosine Deaminase Acting on RNA
- often works near splice sites, changing adenosine to inosine.
- inosine has similar properties to guanine
What are the four types of polarizing distribution?
Posterior, anterior, terminal, or dorsoventral
What role does the 3" UTR play?
This is where transport proteins bind the mRNA
What exonuclease shortens Poly-A tails?