PARP-1 downregulates and YY1 upregulates <i>Cxcl12</i> promoter activity.

<p>(A) Constructs used in transfection experiments: pMDICluc – control plasmid; the luciferase gene was driven by the CMV promoter; pCXCL12luc – reporter construct; the luciferase gene under the control of the <i>Cxcl12</i> promoter; pECV PARP – PARP-1 cDNA expression construct; pcDNA3.1FLAGYY1– expression vector containing a YY1 expression unit. pMDICluc and pCXCL12luc constructs were used for transfection of (B) Rin-5F wt and clone #1 cells and (C) NIH3T3 (PARP^+/+) and NIH3T3 (PARP^−/−) mouse embryonic fibroblasts. Activity of the <i>Cxcl12</i> promoter was expressed relative to the activity of the control CMV promoter. (D) Transfection of NIH3T3 cells with pCXCL12luc and combined pCXCL12luc/pcDNA3.1FLAGYY1 constructs. Overexpression (OE) of YY1 was confirmed by immunoblot analysis with anti-YY1 antibody (figure inset): lane 1– NIH3T3 cell lysate; lane 2– NIH3T3 cell lysate after pcDNA3.1FLAGYY1 transfection. Transfection with pCXCL12luc or with the combination of pCXCL12luc/pECV PARP was performed in (E) NIH3T3 (PARP^+/+) cells and (F) NIH3T3 (PARP^−/−) cells. PARP-1 overexpression (OE) was verified by immunoblot analysis (figure insets): lane 1– NIH3T3 cell lysate; lane 2– NIH3T3 cell lysate after pECV PARP transfection. Statistical significance (*) p<0.05. All results are expressed as the means±SEM, obtained from three separate experiments performed in triplicate.