transcription 5 Flashcards
what does the phosphorylation of the C-terminal domain allow
loading of rna processing machinery
what are the 5 alterations done to rna transcript
- 5’ cap added
- 3’ processing and polyadenylation
- splicing
-editing
-transport
what is splicing
removal of introns
how do we know what is an exon and an intron
they have conserved motifs that indicate the start and end
what reaction are introns removed by
transesterification
how is the 5’ splice site cleaved
the OH group from the branch point attacks the 5’ splice site
what happens to the intron when the 5’ is spliced
the intron will fold back on itself
how do we cleave the 3’ splice site
the OH from the 5’ site attacks the 3’
what splices the gene and when is it produced
spliceosome
assembled as the gene is transcribed
what is a spliceosome made of and what does it use
rna and protein which form snRNPs
atp
what will the snRNPs contain
a complementary strand the splice site
what are the three steps of rna splicing
- commitment/ early complex
- pre-spliceosome/ complex a
- spliceosome formation
what binds at the 5’ splice site
U1 snRNP
what binds at the branch point
branch point binding protein
what binds at the 3’ splice site
U2AF35
what will happen in step 2
u2 snrnp binds to branch site and creates a buldge
what will happen in step 3
u 4, 5 and 6 bind and brings the splice sites together
what are the three types of rna splicing
- nuclear pre-mrna splicing
- group 1 self-splicing
- group 2 self- splicing
what are two errors that can occur in splicing
-exon skipping
-cryptic splice site
what proteins are important for splice site selection
SR proteins
what are the sr proteins that bind to sequences
exonic splicing enhancers
what is alternative splicing and what does it lead to
when rna can be spliced in more then one way and can lead to 2 or more proteins from the same gene
what is rna editing
when information changes at the level of mrna
when would gene editing be needed within the liver
when a stop codon is needed to stop making amino acids
what enzyme converts cytosine to uracil
cytosine deanimase
when is rna editing needed in the ns
when converting in glutamine receptors
from glutamine to arginine
what disease causes low beta globin amounts in haemoglobin
beta thalassemia
what is beta thalassemia caused by
mutations in the tata bo, 3’ and coding region
