Figure 1. Expression of an AcGFP reporter gene is inhibited by 3′-UTR-located inverted Alu repeats . (A) Schematic representation of AcGFP expression constructs. The AcGFP gene of all constructs is expressed from the CMV promoter. (B) western blot analysis of total AcGFP protein shows significantly reduced AcGFP protein levels in 293 cells transfected by an AcGFP expression construct with 3′-UTR inverted Alus (lane 4) relative to cells transfected with an AcGFP control (lane 1). The expression level of AcGFP protein was determined by western blot 48 h post-transfection and normalized to that of β-galactosidase as a transfection control and to α-tubulin as a loading control. Figures are representative of five independent experiments. **p = 0.0031, paired t-test. (C) Bar graph densitometry of western blot bands expressed in arbitrary units. Data are expressed as mean normalized expression, using β-galactosidase and α-tubulin, and are presented as means ± s.e.m. of five independent experiments. The value obtained from the control vector, pAcGFP1-C1, was set to 1. Quantification of images was done by scanning densitometry with NIH Image J 1.54 software (National Institutes of Health, Bethesda, MD, USA).