Platinum Es/Ec Retroviral Expression System, Pantropic Assay Kit

Background: Retroviral gene transfer is a technique for efficiently introducing stable, heritable genetic material into the genome of any dividing cell type. With Moloney Murine Leukemia Virus (MMLV) - based vectors, transduction efficiencies of >90% are achievable for most mitotic cell types, and the copy number per cell can be easily controlled by varying the multiplicity of infection. Current retroviral gene transfer technology is based on the coordinated design of packaging cell lines and retroviral expression vectors. The packaging cell line usually contains the viral gag, pol, and env genes, necessary for particle formation and replication, these genes are stably integrated into the packaging cell genome. Retroviral expression vectors provide the packaging signal ?+, transcription and processing elements, and a target gene. Inserts of up to 6.5 kb can be efficiently packaged. Transfection of the retroviral vector into a packaging cell line produces high-titer, replication-incompetent virus (Table 1). The viral env gene, expressed by the packaging cell line, encodes the envelope protein, which determines the range of infectivity (tropism) of the packaged virus. Viral envelopes are classified according to the receptors used to enter host cells (Table 1). Ecotropic virus can recognize a receptor found on only mouse and rat cells. Amphotropic virus recognizes a receptor found on a broad range of mammalian cell types. Pantropic virus, such as retrovirus pseudo-typed with the envelope glycoprotein from the vesicular stomatitis virus (VSV-G), can infect both mammalian and non-mammalian cells. Unlike other viral envelope proteins, VSV-G mediates viral entry through lipid binding and plasma membrane fusion. However, stable expression of the VSV-G envelope protein is toxic, pantropic virus is usually produced by transiently cotransfecting a retroviral expression vector and pVSV-G into a pantropic packaging cell line expressing only the viral gag and pol genes. Conventional NIH-3T3 based retroviral packaging cell lines and Phoenix packaging cell lines have limited stability and produce low viral yields, mainly due to poor expression level of the retroviral structure proteins (gag, pol, env) in the packaging cells. The Platinum Packaging Cell Lines, potent retrovirus packaging cell lines based on the 293T cell line, were generated using novel packaging constructs with an EF1alpha promoter to ensure longer stability and high-yield retroviral structure protein expression (gag, pol, env). Platinum cells can be kept in good condition for at least 4 months in the presence of drug selection, and can produce retroviruses with an average titer of 1 x 106 infectious units/mL by transient transfection. In addition, replication competent retroviruses (RCR) are virtually nonexistent because only coding sequences of viral structural genes are used, avoiding any unnecessary retroviral sequences. Pantropic Platinum ES/EC Retrovirus Expression System provides a simple method to generate RCR-free pantropic retrovirus at high titer. The kit includes Plat-GP packaging cells, pCMV-VSV-G, pMCs-Puro retrovirus expression vector and pMXs-GFP control vector. pMCs retroviral vector includes hybrid LTRs containing elements from both MMLV and PCMV and is capable of expressing genes in both EC and ES cells.

Small volumes of Platinum ES/EC Retroviral Expression System, Pantropic assay kit vial(s) may occasionally become entrapped in the seal of the product vial during shipment and storage. If necessary, briefly centrifuge the vial on a tabletop centrifuge to dislodge any liquid in the container`s cap. Certain products may require to ship with dry ice and additional dry ice fee may apply.

MBS169406 is an assay kit targeting Platinum ES/EC Retroviral Expression System, Pantropic.