Role of PARP-1 and PARP-2 in the expression of apoptosis-regulating genes in HeLa cells.

Poly (ADP-ribose) polymerase-1 (PARP-1) is a DNA-binding enzyme involved in DNA damage processing, apoptosis, and genetic stability. Many lines of evidence suggest that PARP-1 is implicated in transcriptional regulation of various genes through the modulation of chromatin structure or through direct interaction with transcription factors and/or transcription factor-binding sites. In the present study, we applied TaqMan Low-Density Array analyses to investigate the expression of genes involved in apoptotic cell death induced by an alkylating agent. Using RNA interference, we determined the roles of PARP-1 and PARP-2 in transcriptional regulation during apoptosis in HeLa cells. Of the 93 genes monitored, 33 differentially expressed genes were identified after induction of apoptosis. Whereas the down-regulation of PARP-1 and PARP-2 had no impact on gene expression per se, we observed that Bcl10, c-Rel, and tumor necrosis factor-related apoptosis-inducing ligand receptor-1 and -2 are differentially expressed after induction of apoptosis in a PARP-1-dependent manner. These findings suggest that PARP-1-but not PARP-2-is required for proper expression of major genes involved in regulation of apoptosis.