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The Cignal Lenti Reporters are ready for transduction
right out of the box. There is no need to generate or propagate lentivirus
in your laboratory. These vectors are extremely useful for transient
transduction studies in difficult to transfect cells or for pathway sensor
cell line generation.
Transient Pathway Regulation Studies in Difficult to
Transfect Cells: Target cells are transduced with the Cignal Lenti
Pathway Reporter. The cells are typically cultured for 24 to 48 hours to
insure lentivirus integration. The cultures are then treated with the
biological agents of interest (siRNA, shRNA, chemical compound, viral
expression vector, protein, peptide). Reporter assays (firefly luciferase
or GFP) are carried out 18 to 36 hours post-treatment, depending upon the
treatment conditions.
Pathway Sensor Cell Line Generation: Target cells
are transduced with the Cignal Lenti Pathway Reporter. Following
transduction, the cells are cultured under puromycin selection to generate
a homogenous population of transduced cells. If necessary, single cell
cloning may be carried out in order to isolate a clonal pathway sensor
cell line. These pathway sensor cell lines serve as a valuable cell-based
assay platform, for subsequent screening and mechanism of action studies.
The Cignal Lenti Reporters are ready-to-transduce,
replication incompetent, HIV-based, VSV-G pseudotyped lentiviral particles.
The Cignal Lentiviral particles are safe to use. It is recommended that
they be treated as Risk Group Level 2 (RGL-2) organisms. Follow all
published RGL-2 guidelines for handling and waste decontamination. Details
on the requirements for creating a BSL-2 work environment are available in
the U.S. Department of Health and Human Services publication Biosafety
in Microbiological and Biomedical Laboratories, 4th edition.
The biosafety features engineered into these vectors include:
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A deletion in the promoter/enhancer region of the U3 portion
of 3'LTR ensures self-inactivation of the lentiviral construct after
transduction and integration into the genomic DNA of target cells.
- The Cignal Lentiviral vector and plasmids expressing packaging proteins
contain no significant areas of homology, thereby minimizing any chance for
recombination.
-
None of the HIV-1 genes (gag, pol, rev) will be expressed in
transduced cells, as they are expressed from packaging plasmids lacking
packaging signal. Therefore, the lentiviral particles that are generated are
replication-incompetent
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No virulence genes ( vpr, vif, vpu and nef) are present in
the Cignal Lentiviral vector.
| Feature |
Function |
| RSV-5' LTR; Hybrid Rous sarcoma Virus (RSV)
enhancer/promoter-U5 long terminal repeat |
Permits viral packaging and reverse
transcription of viral mRNA |
| Psi; Packaging signal |
Allow viral packaging |
| RRE; Rev response element |
Involved in packaging of viral transcript |
| cppt; Central polypurine tract |
Involved in nuclear translocation and
integration of transduced viral genome |
| Reporter gene (firefly luciferase or GFP) |
Allow quantification of transcription |
| hPGK; human phosphoglycerate kinase
eukaryotic promoter |
Permits high-level expression of the
mammalian selection marker (puromycin) |
| PuroR; puromycin resistance gene |
Can be used for mammalian selection |
| SIN/3'LTR; 3' self inactivating long terminal
repeat |
Modified 3'LTR that allows viral packaging
but self inactivates the 5'LTR for biosafety purpose. The element also
contains a polyadenylation signal for efficient transcription
termination |
| f1 ori; f1 origin of replication |
Origin of DNA replication for bacteriophage f1
|
| AmpR; ampicillin resistance gene |
Allows selection of the plasmid in E.coli |
| TRE; Transcription response element |
Permits regulation of reporter gene
expression by a specific transcription factor |
| TATA box |
Act as an minimal promoter |
Advantage of using Cignal Lenti dual luciferase system: Cignal
Lenti HIF-1 reporter (luc) [1.5X105 TU] transduced around 15,000
HepG2 cells (24 hours before transduction 7,500 cells were plated per well of
96-well plate) with and without Cignal Lenti Renilla control (luc) [3X104
TU]. After 42 hours of transduction, medium was changed to assay medium (Opti-MEM
+ 0.5% FBS + 0.1mM NEAA + 1mM Sodium pyruvate + 100 U/ml penicillin + 100 µg/ml streptomycin). After 48 hours of transduction, cells were treated
with 300 µM of CoCl2 for 18 hours. Luciferase or dual-Luciferase assay was
performed, and promoter activity values are expressed as arbitrary units using a
Renilla reporter for internal normalization. Experiments were done in
triplicates, and the standard deviation is indicated. The utilization of Cignal
Lenti dual-luciferase system (co-transduction of Cignal Lenti Renilla control
along with Cignal Lenti reporter (luc)) improves the fold induction change in
hypoxia signaling activity, as normalization of firefly luciferase activity with
renilla luciferase activity corrects for cell death caused by the treatment.
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