What is a lentivirus particle?

Lentiviruses are a subset of retroviruses, with the ability to intergrate into host chromosomes, and to infect both dividing and non-dividing cells. They are excellent tools to deliver gene expression or knockdown.

How big is a lentivirus particle?

The virions are enveloped, slightly pleomorphic, spherical and measure 80–100 nm in diameter.

What is lentivirus made of?

The lentivirus belongs to the retroviridae family of viruses. The retroviridae genome consists of a single stranded positive sense RNA that is converted into double stranded DNA during the replication process. In most other types of viruses, viral DNA is transcribed into RNA which is then translated into protein.

Do lentiviral vectors contain DNA or RNA?

Gammaretroviruses and lentiviruses are subtypes of retroviruses, which contain an RNA genome that is converted to DNA in the transduced cell by a virally encoded enzyme called reverse transcriptase.

How do lentiviral particles concentrate?

Lentiviral vectors are a versatile tool for gene transfer, because they can efficiently transduce dividing and non-dividing cells and stably integrate their viral DNA into the host genome. So far, the most common way to concentrate lentiviral preparations is to pellet the viral particles using ultracentrifugation.

What is U3 and U5?

The U3 region contains the promoter from which viral RNA transcripts are expressed (7, 36). R and U5 are both important in the process of reverse transcription of the viral RNA into DNA, U5 for the initiation and R for the extension of viral DNA synthesis (7, 26, 48).

What are LTR transposons?

LTR retrotransposons are class I transposable element characterized by the presence of long terminal repeats (LTRs) directly flanking an internal coding region. As retrotransposons, they mobilize through reverse transcription of their mRNA and integration of the newly created cDNA into another location.

How do you concentrate lentivirus?

It is commonplace to concentrate lentivirus by ultracentrifugation to obtain sufficient viral titres to transduce cells at a high MOI and remove contaminating impurities for sensitive in vivo applications. The standard procedure for concentrating lentivirus involves ultracentrifugation at 90,000 g for 90 min [20, 21].

Do you need to concentrate lentivirus?

The routine concentration of the lentivirus requires ultracentrifugation with relative centrifugal force (RCF), typically exceeding 90,000 g8,9,10,11,12,13, to remove impurities and to ensure a high infection rate, especially for in vivo applications.

How do you make a lentiviral vector?

Lentiviral vectors can be assembled through transient co-transfection of the lentiviral vector backbone plasmid with helper plasmids expressing viral packaging functions or by stably transfected packaging cell lines. The first production method is currently a preferred choice because of its greater flexibility.