GENE EXPRESSION SYSTEM

1. Gene expression system-
viral & nonviral gene
Presented by : Aditya Singh
M.Pharm1st year 2nds.
MPH 201T
Pharmaceutics

2. Content
• Introduction
• Mechanism
• Definition
• Nonviral gene transfer
• Viral gene transfer

3. Introduction
• Gene expression system : a complex series of
processes in which the information encoded in a
gene is used to produce a function product such as
protein.
• Gene expression : is assumed to be controlled at
various points in the sequence leading to protein
synthesis.

5. Mechanism
• Transcription : conversion of DNA to RNA.
• Post-transcriptional modification and splicing.
• RNA transport.
• Translation or protein synthesis.
• Protein folding

7. Gene expression
• Definition: the process in which information in
DNA is altered into functional product of gene
is called gene expression.
• DNA is convert in to RNA which turn into a
protein.

8. Nonviral gene transfer
• Injection of naked DNA.
• Physical methods to enhance delivery.
• Electroporation
• Gene gun
• Microinjection
• Hydrodynamic delivery
• Chemical method to enhance delivery
• Oligonucleotides.
• Lipoplexes
• Dendrimers
• Inorganic nanoparticles
• Cell-penetrating peptides.

9. Injection of naked DNA
• Simplest method of non-viral transfection.
• Expression rate is very low as compared to other
methods.
• Cellular uptake of naked DNA is generally inefficient.
• Only possible for certain tissues.
• Requires large amount of DNA.
• Different methods like Electroporation.
• Use of a gene gun can be used for direct injection of
Naked DNA.

11. Physical method to enhance delivery
• Gene gun : In this method DNA is coated on gold
particles and loaded into a device which is similar to
gun and it generates force by which it can penetrate
into the cell.
• Microinjections : refers to the process of using
micropipeete to inject the desired gene.
• Sonoporation : in this ultrasonic frequencies to
deliver DNA into cell.

12. Chemical methods to enhance
delivery
• Oligonucleotides : to inactivate genes involved in
disease process.
• Different approaches are used for Oligonucletides based Gene
therapy :
• 1. Using antisense specific to the target gene which distrupts
the transcription of faculity genes.
• 2. By using siRNA to singnal the cell to cleave specific
sequences in the mRNA transcript of the faulty genes which
results in distruption of translation.

13. • Dendrimers : It is a highly branched macromolecule with
a spherical shape.
• It is possible to construct a cationic dendrimers, i.e one with a
positive surface charge.
• DNA or RNA with opposite charge binds with cationic
dendrimers.
• On reaching its destination the dendrimer-nucleic acid
complex is then taken into the cell via endocytosis.

14. Viral vector transfer
Virus are obligate intracellular parasites.
Very efficient at transferring viral DNA into host
cells.
Specific target cells depending on the
attachment proteins ( capsid or glycoproteins).

15. • Adenoviral vectors : non-enveloped ds DNA, 36
kilobases.
• Early proteins (E1A, E1B, E2, E3 and E4), late proteins (L1-L5).
• Causes a benign respiratory infections in human.
• Serotypes 2 and 5 are commonly used as vector.

16. • Retroviral vector : Moloney murine leukemia virus.
Generation of replication defective retroviral vector : transfer
plasmid vector, gene of interest, long terminal repeats, primer
binding site, packaging vector.
• Adino-associated virus vector : Non-pathogenic
human parvovirus, non-eneloped ss DNA virus, 4.6 kilobases
and dep.endent on helper virus for replication

17. THANKING
YOU……