Expression of HSA gene on different vectors in primary equine skin (a), lung (b), kidney (c) and dudenum (d) cells. The cells were transfected simultaneously with HSA vectors and pBudCE4.1/lacZ/CAT control vector using Lipofectamine 2000, cultured for 48 h, harvested and applied to Western blot. Control (C) cells treated the same way without DNA. HSA vectors: pcDNA3.1/GS (G1), pcDNA3.1/V5-His (H1), pcDNA3.1/V5-His with intron A (H2), gWIZ (W1), gWIZ with Kozak (W2), VR1012 (V1) and VR1012 with Kozak (V2). The 75 kDa HSA band and the 30 kD CAT band from the pBudCE4.1/lacZ/CAT plasmid is indicated. The vectors were tested at least 3 times in each cell line.