Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

CMB2001 > L7-8: Post transcriptional control of gene expression I > Flashcards

L7-8: Post transcriptional control of gene expression I Flashcards

1
Q

prokaryotic txn and translation

A

one compartment
coupled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

eukaryotic txn and translation

A

separate membrane compartments
txn in nucleus moved to cyto for tln
uncoupled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

stages of eukaryotic gene expression

A
  1. txn control
  2. RNA processing control
  3. tln control
  4. protein activity control

reg at each stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

eukaryotic mRNA structure

A
  1. m7 Gcap structure
  2. start codon
  3. coding region
  4. stop codon
    5
  5. polyA tail

start codon > AUG
poly A = ~250 A’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

m7 Gcap and polyA tail

A

specific to euk mRNAs
post-txn added
encoded in genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

capping

A

coupled to txn via RNA pol II
C-Terminal Domain as binding site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

intron conserved sequences

function?

A

define limits of exon/ intron
recruit splicing machinery for intron removal / exon joining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

2-step intron splicing

2 step esterification

A
  1. cut at 5’ splice site
  2. cut at 3’ splice site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

5’ m7 Gcap structure

A

all RNA pol II RNAs
initially contains triphosphate at 5’
sugar phosphate bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

5’ m7Gcap synthesis

A
  1. GpppN structure
  2. methylation

methylation alters base chemical behaviour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

m7 Gcap functions

A

protects RNA from degardation by 5’-3’ nucleases
facilitates splicing/ export from nucleus
critical for mRNA translation
protein-binding element

important for mRNA production/ stability/ function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

M7 Gcap function mediation

A

CBP80/20 in nucleus
elf4 in cytoplasm

via protein binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

alternative splicing

A
  1. txn and capping// introns cut out for exon joining> forms pre-mRNA
  2. splicing and polyadenylation (non-coding removed) > forms mRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Intron length

A

no. length of introns vary per gene
usually 80-10,000 nt long

intron length> exon length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

dystrophin

A

gene linked to Duchenne muscular dystrophy
1 intron
21000 nt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

intron conserved sequence components

A

5’ splice site
3’ splice site
branch site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

cut at 5’/3’ splice site in 2 step esterification

A

5’> bond formed between 5’ end of intron and branch site
3’> release intron lariat/ ligation of 2 exons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

spliceosome

A

enzymatic complex that catalyzes intron removal

complex of >200 proteins assembling onto each intron

(proteins: RNA-binding/ ATPases/ GTPases/ snRNPs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

snRNPs

A

small nuclear ribonucleo-protein particles
stable RNA-protein complexes in nucleus
not RNA coding
catalyse splicing
Sm ring (binding site of RNA)

U1/2/4/5/6 in spliceosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

snRNP base-pairing w conserved sequences in intron

A

U1> 5’splice
U2> branch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

SLE

systemic lupus erytematosus

A

~20% have anti-Sm

anti-Sm Ig react against Sm proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

txn and splicing

A

functionally coupled
yeast U1/U2 pair to pre-mRNA

23
Q

no. conserved sequences in splicing

24
Q

no. introns in S.cerevisiae vs C.elegans

A

minimal splicing/ introns in S.cerevisiae
many introns in human genome/ C.elegans

25
alternative splicing function
key for multiple protein isoforms from one gene
26
types of alternative splicing
exon skipping intron retention mutually exclusive exons alternative 5'/3' splice site | during embryonic development
27
activators | in regulation of cis-acting sequences in pre-mRNA
bind to intronic/ exonic splicing enhancers ISE/ESE | intronic/exonic splicing enhancers
28
repressors | in regulation of cis-acting sequences in pre-mRNA
bind to intronic/ exonic splicing silencers
29
mutations causing splicing defects
spinal muscular atrophy (infant mortality) retinitis pigmentosa (blindness/ vision defects) myotonic dystrophy (muscle-wasting)
30
polyadenylation | 2 stages
1. endonuclease cleavage 2. addition of As by polyA polymerase
31
conserved sequence for polyadenylation | other features of polyadenylated mRNA?
AAUAAA 10-35nt up of poly(A) site | G/U or U rich tract downstream of poly(A)/ USE ## Footnote proteins bind to these sequences
32
USE
U-rich upstream element
33
protein binding AAUAAA
Cleavage and polyadenylation specificity factor | CPSF ## Footnote cleavage factors I/II
34
protein binding G/U
cleavage stimulatory factor | CstF
35
poly(A) tail | no. nt? location?
250 nt 3' on all mRNA bound by poly(A) binding protein
36
poly(A) tail function
^RNA export/ mRNA tln protein-binding element stabilizes 3' end of mRNA
37
2 RNA editing classes | where does it occur
insertion/ deletion modification | mRNA/tRNA/rRNA
38
RNA editing in medicine/ development
atherosclerosis brain function improvement drosophilia development parasites (trypanosoma leishmania/ trypanosoma)
39
base modification | functions
middle group addition aids protein-binding flipping purines/ pyrimidines | marked nucleotide/ altered identity
40
effects of mRNA editing
U-insertion> start-codons/ stop-codons nt insertion> new ORF's change in encoded aa/ splice site by base conversion stop codons removed by base conversions | C> U changes
41
enzymatic deamination
adenosine> inosine cytosine> uracil | inosine recognised as guanosine
42
cytidine deamination | apoB pre-mRNA editing
- APOBEC-1 enzyme carrying out cholesterol control/ Cancer development/ viral replication inhibition - 2 forms(48/100) circulate in blood w different functions 100> liver w/o editing
43
2 forms of APOBEC-1
48> intestine w editing 100> liver w/o editing/ long form component of LDL (atherosclerosis linked)
44
L-glutamate
major excitatory neurotransmitter
45
A> I editing in Q/R site of glutamate
decreases Ca2+ permeability of 'R' channels carried out by ADAR2
46
ADAR2
Adenosine Deaminase on RNA
47
ADAR2 mutations
seizures/ post-natal death/ neurodegeneration in hippocampus
48
nucleotide modification
nt modification after txn results in changes in protein binding> changes in RNA properties/ sequences | editing on ncRNAs also> essential for function
49
mRNA export from nucleus to cytoplasm
nucleopores in nucleoplasm via nuc basket cyto/proximal filaments central transporter cyto/inner spoke/ nucleoplasmic ring | different pathways mediate export of different RNAs
50
mRNA localisation fucntion
localised protein synthesis cell polarity generation prevents expression in wrong place ^protein targetting efficiency tln control
51
dendritic mRNA localisation
tln local for synaptic plasticity/ spine morphogenesis
52
mRNA localisation by diffusion
mRNA's freely diffuse in cytoplasm/ locally entrapped by anchor proteins
53
active transport- based localisation
- mRNA recognized by specific trans-acting factors in nucleus - cytoplasmic factors ensure transport along polarized cytoskeleton
54

CMB2001 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions