retroviral vectors

1. Retroviral Vectors
By:
Maryam shakeel

2. Retrovirus
Class of enveloped viruses
Single stranded RNA
Retroviruses are one of the mainstays of
current gene therapy approaches.
The recombinant retroviruses such as the
Moloney murine leukemia virus have the
ability to integrate into the host genome in a
stable fashion

5. Genome of Retrovirus
• LTR (long terminal repeat)
U5 envpolgag5’ 3’
• PBS (primer binding site)
• “Pol” gene
• “gag” gene
• “env” gene
• “Ѱ” packaging signal site
• 5’ss & 3’ss site
Ѱ
5’ss 3’ss
U3 R U5U3 R
LTR LTR
• PPT (polypurine Test)

6. Construction of Replication
defective Retroviral Vector:
• Retroviral vectors are derived from wild type
retroviruses (Moloney murine leukaemia
provirus) and are engineered to carry a
foreign gene of interest into a target cell.
• Retroviral vectors are composed of the gene
of interest and the cis-acting elements of the
viral genome , with the removal of the trans-
acting viral genes (gag, pol, and env)

7. LTR LTRenvpolgag5’ 3’
Ѱ
5’ss 3’ss
LTR LTR5’ 3’
Ѱ
5’ss
Gene of Interest

8. Applications in Gene therapy:

9. Limitations:
• Moloney retrovirus involves the requirement
for cells to be actively dividing
for transduction.
• insertional mutagenesis due to integration
into the host genome might lead to
cancer or leukemia.

10. Thanks