Ionising radiation induces the expression of PARP-1 and PARP-2 genes in Arabidopsis

Abstract

By screening for Arabidopsis genes activated by ionising radiation (IR)-induced DNA damage, we have isolated a cDNA hybridising with a 3.2-kb mRNA that accumulates rapidly and strongly in irradiated cell suspensions or whole plants. The cDNA codes for a 110-kDa protein that is highly homologous to the 116-kDa vertebrate poly(ADP-ribose) polymerase (PARP-1). It is recognised by a human anti-PARP-1 antibody, binds efficiently to DNA strand interruptions in vitro, and catalyses DNA damage-dependent (ADP-ribose) polymer synthesis. We have named this protein AtPARP-1. We have also extended our observations to the Arabidopsis app (AtPARP-2) gene, demonstrating for the first time that IR-induced DNA strand interruptions induce rapid and massive accumulation of AtPARP-1 and AtPARP-2 transcripts, whereas dehydration and cadmium preferentially induce the accumulation of AtPARP-2 transcripts. The IR-induced PARP gene expression seen in Arabidopsis is in striking contrast to the post-translational activation of the PARP-1 protein that is associated with genotoxic stress in animal cells. AtPARP-1 transcripts accumulate in all plant organs after exposure to ionising radiation, but this is followed by an increase in AtPARP-1 protein levels only in tissues that contain large amounts of actively dividing cells. This cell-type specific accumulation of AtPARP-1 protein in response to DNA damage is compatible with a role for the AtPARP-1 protein in the maintenance of DNA integrity during replication, similar to the role of "guardian of the genome" attributed to its animal counterpart.

Analysis of Poly(ADP-Ribose) Polymerases in Arabidopsis Telomere Biology

“…Compared to untreated controls, PARP1 expression was increased 66-fold (p-value = 0.00015) and PARP2 increased by 8-fold (p-value = 0.0001) (Figure 2B). Although the increase in PARP1 and PARP2 was expected based on previous reports [88], [89], the expression of PARP3 in response to DSBs has not been described. In either treated or untreated seedlings, the qRT-PCR signal for PARP3 was either not detected or was extremely low (C t ≥34) (Figure 2B), suggesting that PARP3 is not upregulated in response to DNA damage in seedlings, and therefore has separate functions from PARP1 and PARP2.…”

The RST and PARP-like domain containing SRO protein family: analysis of protein structure, function and conservation in land plants

“…Some additional plant specific folds not present in the HsPARP1 are predicted in AtPARP1 and 2, AtRCD1 and AtSROs (Figure 11A and 11B). These additional predicted features, if present, apparently do not disrupt the activity in AtPARP1, which was shown to exhibit PARP activity (Table 2; [44]). The conserved active site folds also mark the position of the catalytic triad, the three AAs histidine (H), tyrosine (Y) and glutamic acid (E), which is conserved in AtPARP1 and 2 but not AtRCD1 or AtSROs (Figure 11A and 11B; Table 2).…”

ATR cooperates with CTC1 and STN1 to maintain telomeres and genome integrity inArabidopsis

“…To investigate this possibility, we monitored the expression of several transcripts implicated in the DDR ( RAD51 , BREAST CANCER SUSCEPTIBILITY 1 [ BRCA1 ]) and ( poly [ADP-ribose] polymerase 1 [ PARP1 ]; Doucet-Chabeaud et al , 2001; Lafarge and Montané, 2003; Yoshiyama et al , 2009). Quantitative real-time (RT)-PCR was performed using cDNA made from first-generation (G1) ctc1 flowers.…”