Cotransfection

Cotransfection refers to the simultaneous transfection with two separate nucleic acid molecules, such as plasmid DNA and siRNA. Cotransfection is a common procedure for stable transfection. The plasmid DNA may contain a gene that is easily assayed and acts as a marker.
 
For this to occur, a marker gene is co-transfected, which gives the cell a selection  advantage, for example resistance towards a certain toxin. Selecting the right reagent for co transfection is essential.

Lipofectamine® 2000

Lipofectamine® 2000 Reagent is a proprietary formulation that facilitates highly efficient delivery of short interfering RNA (siRNA) or plasmid DNA to mammalian cells.

Cotransfection Protocol with Lipofectamine® 2000

This reference provides general guidelines and a procedure to cotransfect plasmid DNA and an RNAi molecule (i.e. RNAi, siRNA, shRNA plasmid or miRNA plasmid) into mammalian cells using Lipofectamine™ 2000 Reagent are described in this section.