Python Notes for mca i year students osmania university.docx
Coronavirus and NMD (nonsense mediated mRNA decay)
1. A
PRESENTATION ON
ADVANCED MICROBIOLOGY
Presented by
MD ROBEL AHMED
STUDENT ID:
L20192E020101
1ST YEAR 1ST SEMESTER
(Master’s)
FACULTY OF LIFE SCIENCE
AND MECICINE
Presented to
XIUFANG HU
PROFESSOR ,
FACULTY OF LIFE SCIENCE AND
MEDICINE
ZHEJIANG SCI-TECH UNIVERSITY
DATE OF PRESENTATION: 12th MAY 2020
2.
3. RNA Decay
► Post transcriptional quality control pathway.
► Intrinsic conserved mechanism in Eukaryotic organisms like plants and animals
► Detect and disrupt mRNA having negative activity.
► mRNA have to harvour PTC, uORF, long 3’ UTR sensitive to decay.
4. Nonsense Mediated Decay
Detects mRNAs harboring aberrant features.
Due to alternative splicing or mutation in nonsense bases of DNA.
Degrades target via various exo-nuclease pathway.
NMD inducing features
uORF with PTC
Long 3’UTR
Viral RNA with (iTC).
5. What is nonsense?
A T G C A G C A G C A G C A G C A G C A G C A G C A G
Start Gln Gln Gln Gln Gln Gln Gln Gln
A T G C A G C A G C A G C A G C A G T A G C A G C A G
Start Gln Gln Gln Gln Gln ? Gln Gln
A U G C A G C A G C A G C A G C A G U A G C A G C A G
Start Gln Gln Gln Gln Gln STOP Codon Gln Gln
mRNA
Truncated protein
Anti-sense
Sense
7. Genomic Information of Coronavirus
Plus sense (+) single stranded RNA (ssRNA) genome
Genome length is about
The virus is cytoplasmic origin
Lifecycle is common like other + sense viruses.
8. Coronavirus and NMD
Murine Hepatitis Virus (MHV) as a Model CoV.
Hypothesis is that CoV genomic and sub-genomic RNA like rLucRNA3 is
susceptible to NMD.
9. RESULT
MHV genomic RNA is a NMD target
Weather depletion of host NMD factor enhances viral replication ?
Or not?
If so happened, virus may be NMD target.
17Cl-1 cell transfected with
NMD reporter plasmid NS39 having PTC
Or Wild type reporter plasmid not have PTC.
qRT-PCR result shows that NS39 is a NMD target.
Conc. Of NS39 transcript raised high in cells depleting NMD factors.
10. NMD negative cell with MHV
genomic RNAs (M protein)
Number of M protein positive
cell increased
Number of virus titer also
increased
RESULT
11. Degradation kinetics of MHV genomic RNA
NMD deficient cell:
• Level of genomic RNA is Higher
RESULT
NMD competent cell:
• qRT-PCR result showed no
substantial increase in the levels of
genomic RNA.
13. MHV N Protein Inhibits the
NMD Pathway
Viral protection of incoming
MHV genomic RNA from
NMD.
Cells transfected with
NS39 plasmid
Wild Type plasmid
Along with CAT or TGEV-nsp1
RESULT
Level of NS39 higher in TGEV-nsp1 expressing cell than CAT
expressing cell, indicate TGEV-nsp1 inhibit NMD
14. RESULT
To further confirm, stable cells
transfected with NS39 or Wild type
plasmid in the presence of N
protein or TGEV-nsp1
Levels of NS39 reporter transcripts were higher in cells
expressing MHV N or TGEV nsp1, but not CAT,
17. Discussion
Out study shows a common interplay between CoV and NMD
In Host cell Depletion of NMD done by
Silencing essential NMD factors as UPF1, UPF2,
SMG proteins and others
Chemically cellular NMD silenced by CHX and
wortmannin.
Result shows that CoV genomic and sub-genomic
RNA are attacked by host cellular NMD machinery
subsequently try to be resistant for multiplication.
MHV N protein is an important protein helps virus to
be resistant against Nonsense mediated decay.
18. Copyright: All design and figure made by Ahmed Md Robed. It is illegal to copy of them.