Representative slot blot analysis of the retroviral titers of the supernatant for the M-GFP and L-GFP vectors used in our co-transduction assay.

Equal volumes of each supernatant were taken, viral RNA was extracted, and serial 10-fold dilutions were analyzed by slot blot analysis, using a GFP probe. The titers were compared with a control supernatant from an Ecotropic-GFP-MLV producer cell line of which the titer was known.