All transfections were carried out with TransIT LT1 (Mirus) according to the manufacturer's instructions. A ratio of 2 or 3 ml LT1 per mg DNA was used. Cells were plated at 10 5 per well in 12well plates 1 day before use. Usually, 24 hours post transfection the medium containing the transfection mix was removed and replaced with fresh medium. The cells were then lysed in 200 ml lysis buffer (120 mM NaCl, 50 mM TrisCl pH 7.5, 0.05% Nonidet P-40). The samples were centrifuged for 1 min at full speed in a table top centrifuge. 50 ml of the cleared cell extract was taken and the luciferase activity was measured after adding 50 ml of luciferase assay reagent (Promega) to each sample. The following settings were used to measure the relative light units: integration time: 10 sec, sensitivity: 200 or 230 and Filter set 1. To determine the b-galactosidase activity 150 ml of assay buffer (48 mM Na 2 HPO 4 , 32 mM NaH 2 PO 4 , 8 mM KCl, 0.8 mM MgSO 4 , 3.2 mg/ml o-Nitrophenyl b-D-Galactopyranoside) were added to the samples after the luminescence was measured. The samples were incubated at 37uC for 30 min to 60 min before absorbance at 420 nm was measured. The luminescence and absorbance measurements were done in a Synergy 2, Multi Detection Microplate Reader (BioTek Instruments) using Gen5 software. The values were normalised and statistically analysed as previously described [63] .