ch 11 Flashcards
nuclear exosome
group of proteins that will break apart RNA that need to get got
cytoplasmic exosome
degraded after translation
after mRNA is done being translated and read this is done
rapid degration is done by
nonsense mediated mRNA decay
RNAi/ RNa interference
RNA is actively degraded, no translation
introns
removed from RNA, may have another function
exons
coding sequence for polypeptide, stuck together
primary RNA transcript
initial RNA before cutting
splice sites
where shit gets cuts, denotes the 5’ and 3’ sites
GU and AG
5 major splicing mechanism
1/2. autocatalytic group I and II introns
3. tRNA introns
4. arhcela introns
5. spliceosomal introns
splicosome
complex of riboprotiens that cut shit
where do the three mRNA maturing processes take place
c terminal of rna poly
what order does this shit occur in
- 5’ cap
- other shits
5’ cap contains
7 methylated guanosine
5’ cap function
- protect mRNA (from splicosome)
- facilitates loading onto small ribo subunit
- facilitate splicing
- 3’ end formation
- nuclear export
end sequence for poly tail to add
aauaaa, gu rich added by poly a polymerase (PAP)
aauaaa recognized by
- cleavage and polyadenylation specificity factor
- cleavage stimulation factor
RNa poly is terminated in part by
Xrn2 exonuclease
it chases RNA poly II and chews its ass
poly A tail is coated with
pabpn1 (binding protien), coated until it leaves
what gives rise to oculopharyneal muscular dystrophy
mutations is PABP1 (binding protein on poly a tail)
largest and most complex molecular machine
spliceosome
snRNAs and SM common core proteins invloed in splicing
5 snRNP (snurps)
snRNA names
U1-6, no 3 tho
5’ end sequence
GU
3’ end sequence
AG
ESE or ESS can- the splicing that will occur
silence or enhance
alternative splicing
changing exon arrangement, variety (skipping and stuff)
why is ok to only have small number of genes
alternate splicing- makes splice variants
CaMKII delta has many isoroms due to
alt splicing, diff cellular locations
cis splicing
exon on same gene get spliced together
trans splicing
exon on different genes get splicing together (intra genetic, inter genetic, exo, endo)
exo and endo spicing take dna form
plasmids
RNA editing (post trans)
changing nucleotides after transcriptions
RNA editing examples
adenine to inosine
cytidine to uridine
siRNA/ short interfering RNA
Silences same or similar locus from which they originate- from virus or eco genes
miRNA
derived from unique genes that silence very diff genes
dicer
processes dsRNA into shopt ds siRNA
RISC
makes siRNA single stranded license thru RNA deflation or translation repression
miRNA and siRNA difference
miRNA- encoded by organism
siRNA- external source
what could silence dsRNA viruses
siRNA
intron types
Autocatalytic Group I and Group II Introns,tRNA introns
* Archaeal introns
* Spliceosomal introns
first transesterfication
The 2’-hydroxyl group of the branch point adenosine nucleotide attacks the 5’-splice site, forming a lariat structure
second transesterfication
The 3’-hydroxyl group of the 5’-exon attacks the 3’-splice site, releasing the intron and joining the exons together.
5’ cap added when
first
CPSF
Cleavage behind the AAUAAA sequence is partly mediated b
