Is retrovirus an enveloped virus?
Retroviruses (family Retroviridae) are enveloped (about 100 nm in diameter), icosahedral viruses that possess a RNA of about 7–10 kb. Retroviruses are divided into two classes: simple retrovirus and complex retrovirus (ie, lentivirus or HIV).
What is retroviral transduction?
Retroviruses have the ability to transform their single-stranded RNA genome into a double-stranded DNA molecule that stably integrates into the genome of dividing target cells. Retroviral transduction has been widely used for cancer and stem cell research.
What is lentivirus packaging?
We will describe a procedure which to package lentiviruses. Packaging refers to the preparation of competent virus from DNA vectors. Lentiviral vector production systems are based on a ‘split’ system, where the natural viral genome has been split into individual helper plasmid constructs.
What is amphotropic retrovirus?
A Retroviral Expression Vector. Q: What is the difference between ecotropic, amphotropic, and pantropic virus? A: Ecotropic pseudotyped virus can only infect mouse or rat cells, amphotropic can infect most mammalian cells, and pantropic (VSVG pseudotyped) virus can infect cells of any species.
Is influenza virus A retrovirus?
Influenza is an RNA virus that causes mild to severe respiratory symptoms in humans and other hosts.
What is the difference between transduction and transfection?
Transfection is the process of introducing nucleic acids into cells by non-viral methods. Transduction is the process whereby foreign DNA is introduced into another cell via a viral vector. A common way to validate that a genetic material was successfully introduced into cells is to measure protein expression.
What is RetroNectin?
RetroNectin® , recombinant human fibronectin fragment, is a protein of ~63 kDa (574 amino acids) containing a central cell-binding domain (type III repeat, 8, 9, 10), a high affinity heparin-binding domain II (type III repeat, 12, 13, 14), and CS1 site within the alternatively spliced III CS region of human fibronectin …
Why are lentiviruses used?
Lentiviral vectors in gene therapy is a method by which genes can be inserted, modified, or deleted in organisms using lentivirus. Lentivirus are a family of viruses that are responsible for notable diseases like AIDS, which infect by inserting DNA into their host cells’ genome.
Is VSV a lentivirus?
The VSV-G envelope protein is commonly used in lentiviral particle production because it confers broad tropism over a range of species and cell types. For more information, see the Cronin, et al. article on different envelopes and their tropism.
How do you create a retrovirus?
Retroviral vectors are created by the removal of the retroviral gag, pol, and env genes, which are replaced by the therapeutic expression cassette. To produce vector particles, removed gag, pol, and env genes are provided in trans by specific packaging cell lines.
How do you make retrovirus?
We produce retroviruses by transfecting multiple plasmids that between them provide all of the necessary components for vector particle production. However, the genome plasmid does not encode all, or even any, viral genes. Thus the infected cells make the transgene, eg GFP, but no viral genes.
How are lentiviruses different from standard retroviruses?
Lentiviruses are a subtype of retrovirus. From an experimental standpoint the main difference between lentiviruses and standard retroviruses (γ-retroviruses) is that lentiviruses are capable of infecting non-dividing and actively dividing cell types whereas standard retroviruses can only infect mitotically active cell types.
How are envelopes, packaging and transfer used in retrovirus?
The three components described above (envelope, packaging, and transfer) are supplied by three types of plasmids, which are cotransfected into the 293T packaging cell line. This system provides the greatest flexibility to pseudotype γ-retrovirus using different envelopes to modify tropism.
Are there genes required for γ retrovirus to transduce?
Yes, as with lentiviruses, the genes required for γ-retroviral packaging and transduction are not encoded by the transfer plasmid, but instead are provided in trans by other plasmids or the packaging cell line. γ-retroviruses can transduce target cells, but the transduced target cell does not produce additional virus.
How are lentiviral and retroviral vectors used for gene expression?
Utilizing this feature of lentiviral and retroviral vectors allows for the theoretically permanent expression of a gene construct, such as an siRNA or protein coding sequence, in a population of cells, or on a single-cell level [ 6 ].