RNA Processing Flashcards
1
Q
4 types of processing events
A
Polyadenylation, intron splicing, cap and internal methylation.
2
Q
Nucleotide methylation
A
If A is methylated, can be done twice. Methylated not transcribed. Most capped are adenosines in last exon
3
Q
Polyadenylation
A
Recognition, cleavage leaving OH, addition of 250 A. Requires AAUAAA signal. Needs U or GU sequence downstream.
4
Q
What does polyadenylation do?
A
Terminate transcription, proper export, stability and translation.
5
Q
PolyA proteins
A
CPSF- binds AAUAAA CstF- stimulates cleavage CFI- cleaves PAP- adds adenosine PABN1- regulates length
6
Q
Intron splicing
A
Removes introns, needs snRNPs. Has intron lariat with 5’ to 2’ bond. Need 5’ GU and 3’ AG.
7
Q
Can splicing and adenylation be alternative
A
Yes
8
Q
Are histone mRNAs adenylated
A
No
9
Q
5’ end capping
A
Only guanine, which is connected by phosphate bridge to rest
