RNA interference

1. Technical Session -10
COORDINATION AND MONITORING OF COUNTRY
PREPAREDNESS AND RESPONSE
On May 06 to 08 , 2020

2. ROLE OF DNA & RNA IN PROTEIN SYNTHESIS
 DNA is a double stranded nucleic acid
consisting of deoxyribose sugar and carries the
genetic instructions used in the development
and functioning of all known living organisms.
 RNA is a single stranded molecule consisting of
ribose sugar and it is transcribed (synthesized)
from DNA by enzymes called RNA polymerases.
RNA acts as a messenger between DNA and the
protein synthesis complexes known as
ribosomes
 Proteins are one of the vital biomolecules of
life. These compounds perform a variety of
essential processes to sustain an organism's
survival, which include clotting of blood,
transporting oxygen, contracting muscles and
catalyzing chemical reactions. The building
blocks of proteins are called amino acids.
 Two type of sugar found in Genetic materials 1. Deoxyribose sugar 2. Ribose
sugar.
 RNA is a single stranded molecule consisting of ribose sugar.
 It is transcribed (synthesized) from DNA by enzymes called RNA
polymerases
 The building blocks of proteins are called amino acids and their functions
Functions
of RNA

3. SOME ORGANISMS HAVE RNA AS GENETIC MATERIAL
 RNA virus may have ssRNA or ds RNA enveloped in protein
coat
 Have human diseases like SARS, HIV, Hepatitis and Rabies etc
 DNA synthesis in host cell

4. RNA VIRUSES IN PLANTS
RNA Viruses

5. PROTEIN SYNTHESIS
The synthesis of proteins starts with
transcribing the instructions in DNA into
mRNA.
The mRNA is then carried out of the cell's
nucleus into the cytoplasm, specifically into
structures called ribosomes.
Protein production occurs in ribosomes
containing rRNA.
The tRNA transports the amino acids to the
ribosomes.
The code sequence in mRNA is then translated
and specific proteins are synthesised by stringing
amino acids together.
The production or synthesis of polypeptide
chains (proteins) includes two phases:
Transcription & Translation.
RNA is synthesized RNA polymerases which act as messenger
for transports amino acids to ribosomes.
 Proteins are one of the vital biomolecules of life.
specific proteins are synthesized by stringing amino acids
together

6.  Gene “knockdown”
 A cellular mechanism that degrades
unwanted RNAs in the cytoplasm but
not in the nucleus
 A way for the cell to defend itself
MOLECULAR BIOLOGY’S CENTRAL
DOGMA

7. TRANSCRIPTION PROCESS IN
EUKARYOTES
RNA Polymerase:- All eukaryotes possess three type of RNA polymerases called RNA
polymerase I,II and III .
RNA polymerase I is located in nucleolus, and is responsible for transcription of genes for
rRNA, it is responsible for 50-70% of the activity in eukaryotes.
RNA polymerase II is located in the nucleoplasm, constitutes 20-40% of total activity and
transcribes all the genes that produce mRNA.
RNA polymerase III also occurs in nucleoplasm, provides ~10% of total polymerase
activity, and transcribes tRNA and other small RNA genes.
Transcription Factors
Transcription Factors are those points that are essential for transcription initiation, but they
are not a part of RNA polymerases. A large number of transcription factors function with
RNA polymerase II, they are divided into the following three groups: (1) basal, (2) upstream
and (3) regulatory transcription factors.

9. TRANSCRIPTION FACTORS
Basal Transcription Factors:- These factors are required for transcription initiation at
all the promoters. They join RNA polymerase II to form a complex around the start
point, and determine the site of transcription initiation. The different basal factors are
follows:
(1) TFIIA, (2) TFIIB, (3) TFIID, (4) TFIIE, (5) TFIIF, (6) TFIIH, and (7) TFIIJ.
Upstream transcription Factors:- These transcription factors are found in all cell
types and bind to specific short sequences located upstream of the start point. These
factors act on any promoter having the appropriate sequence and increase the
frequency of initiation. Protein (Salmonella pathogenicity island) SPI is an example of
upstream transcription factors.
Regulatory Transcription Factors:- These factors function just like upstream factors,
by they have a regulatory role. They are produced or activated at specific times or in
specific tissues. As a result they control transcription of the concerned genes.
Promoters:- Eukaryotic promoters are defined as regions that can support transcription
at normal efficiency and with the proper control. The organization of promoters for
the three types of RNA polymerases differ markedly. The promoters for RNA
polymerase II usually have the some modules or functional sequence
Enhancer:- An enhancer can stimulate any promoter that is placed in its vicinity. The
essential role of enhancer seems to be to increase the concentration of some of the
transcription factors in the vicinity of the promoter, this they achieve by binding to
these factors.

10. RNA FAMILY AND TYPE OF RNA INTERFERENCE
mRNA- Protein and sRNA= RNA Modification, Translation &
RNA Silencing
1. miRNA- micro
RNA interference
2. siRNA – small
interference
3. shRNA- short
hairpin
interference

11. THE MECHANISM OF RNA INTERFERENCE
 Interference means the act of interfering with something here with RNA.
 RNAi- is a mechanism that inhibits gene expression the stage of translation or by
hindering the transcription of specific genes.
 RNAi targets include RNA from viruses and transposons.-gene expressions
 Also known co-suppression, Post transcriptional gene silencing (PTGS) in plants.
 Quelling in fungi and RNAi in animal kingdom

12. THE RNAi ROLE AND PATHWAYS
Protects against RNA virus infections, especially in plants
Maintain genome stability by keeping mobile elements silent
Represses protein synthesis regulates the development of
organisms
Keep chromatin condensed and suppress transcription

13. THE RNA INTERFERENCE CHARACTERISTICS

14. RNAi INDUCED GENE SILENCING IN
PETUNIA PLANTS
Co-suppression of gene expression
Enhanced tolerance or resistance to
virus infection/ protection and Potent
gene silencing in 1998
A type of gene regulation
Involve small RNA
molecules and
induce a ds RNA
RNAi

16. HISTORY OF RNAi

17. HISTORY OF RNAi

18. RNAi WAS FOUND TO WORK IN MANY DIVERSE
SPECIES

19. NOBEL PRIZE WINNERS IN THE C. ELEGANS FIELD

20. THE MECHANISM OF MiRNA INTERFERENCE

22. THE MECHANISM OF SiRNA INTERFERENCE

24. Difference Between miRNA & siRNA

25. ROLE OF iRNA IN BIOTECHNOLOGY

26. ROLE OF iRNA IN MEDICINES…

27. APPLICATION OF RNA INTERFRENCE IN CROP IMPROVEMENT

28. APPLICATION OF RNA INTERFRENCE IN CROP IMPROVEMENT

34. South Korea based OliX Pharmaceuticals, Inc., a leading developer of RNA interference
(RNAi), has announced that it will leverage previous preclinical research for developing
siRNA therapeutics in treating respiratory illnesses to investigate a path forward for
developing a COVID-19 therapy.
OliX Pharmaceuticals filed a provisional patent application to advance the development of
RNAi therapeutics against COVID-19 on February 25, 2020. The patent provides broad
composition of matter claims to more than 30 small interfering RNAs (siRNAs) designs
that target available genomes of the COVID virus, which are highly conserved regions
compared to other coronaviruses, such as SARS and MERS and can potentially be used
effectively against coronaviruses.
Specifically, the target regions are coding the proteins for playing an important role in virus
replication (e.g., 3CL-protease, RNA-dependent, RNA polymerase, and Spike
protein). The siRNAs would operate within the RNAi pathway, where it interferes with the
expression of the genes with complementary nucleotide sequences by degrading mRNA
after transcription, resulting in no translation.
OliX Pharma employs
RNAi Approach for COVID-19 Therapy
no translation.

35. Antiviral applications of RNAi for coronavirus
Until the appearance of severe acute
respiratory syndrome (SARS), caused
by the SARS coronavirus (SARS-CoV) in
early 2003, coronavirus infection was not
considered to be serious enough to be
controlled by either vaccination or specific
antiviral therapy. It is now believed that
the availability of antiviral drugs effective
against SARS-CoV will be crucial for the
control of future SARS outbreaks.
Recently, RNA interference has been
successfully used as a more specific and
efficient method for gene silencing. RNA
interference induced by small interfering
RNA can inhibit the expression of viral
antigens and so provides a new approach
to the therapy of pathogenic viruses. This
review provides an overview of current
information on coronavirus and the
application of small interfering RNA in
viral therapeutics, with particular
reference to SARS-CoV.