**3.2 Plasmid preparation**

The plasmid pEGFP carries the green fluorescent protein coding region under the control of the cytomegalovirus immediate-early promoter region. It was isolated from Escherichia coli (Stratagene, Amsterdam, NL) with the Maxi-Prep Kit from Qiagen (Hilden, Germany). Isolated DNA was stored in TE buffer (100 mM NaCl, 10 mM Tris-HCl) at a concentration of 1 mg/mL at -20 °C after its purity was verified by determining the ratio of absorbance at 260/280 nm and by gel electrophoresis.
