Abstract:SummaryPoly(ADP-ribosyl)ation is an immediate DNA-damagedependent post-translational modification of histones and other nuclear proteins that contributes to the survival of injured proliferating cells. Poly(ADP-ribose) polymerases (PARPs) now constitute a large family of 18 proteins, encoded by different genes and displaying a conserved catalytic domain in which PARP-1 (113 kDa), the founding member, and PARP-2 (62 kDa) are so far the sole enzymes whose catalytic activity has been shown to be immediately stimu… Show more
“…PARP1 is one of the major enzymes in the PARP family and catalyzes the polymerization of PAR on target proteins 1. PARP1 is a nuclear protein that plays diverse roles in many molecular and cellular processes, including DNA damage detection and repair, chromatin remodeling, and transcriptional regulation 2.…”
PARP1 and poly(ADP‐ribosyl)ation (PARylation) have been shown to be essential for the initial steps of cellular reprogramming. However, the mechanism underlying PARP1/PARylation‐regulated activation of pluripotency loci remains undetermined. Here, we demonstrate that CHD1L, a DNA helicase, possesses chromatin remodeling activity and interacts with PARP1/PARylation in regulating pluripotency during reprogramming. We found that this interaction is mediated through the interplay of the CHD1L macro‐domain and the PAR moiety of PARylated‐PARP1. Chromatin immunoprecipitation assays demonstrated the co‐occupancy of CHD1L and PARP1 at Pou5f1, Nanog, and Esrrb pluripotency loci. Knockdown of CHD1L significantly blocked the binding activity of PARP1 at pluripotency loci and inhibited the efficiency of PARP1‐driven reprogramming. Notably, we found that CHD1L‐promoted reprogramming requires both a PARP1‐interacting domain and DNA helicase activity, partly contributing to the chromatin‐remodeling states of pluripotency loci. Taken together, these results identify CHD1L as a key chromatin remodeler involved in PARP1/PARylation‐regulated early‐stage reprogramming and pluripotency in stem cells. Stem Cells
2015;33:2961–2972
“…PARP1 is one of the major enzymes in the PARP family and catalyzes the polymerization of PAR on target proteins 1. PARP1 is a nuclear protein that plays diverse roles in many molecular and cellular processes, including DNA damage detection and repair, chromatin remodeling, and transcriptional regulation 2.…”
PARP1 and poly(ADP‐ribosyl)ation (PARylation) have been shown to be essential for the initial steps of cellular reprogramming. However, the mechanism underlying PARP1/PARylation‐regulated activation of pluripotency loci remains undetermined. Here, we demonstrate that CHD1L, a DNA helicase, possesses chromatin remodeling activity and interacts with PARP1/PARylation in regulating pluripotency during reprogramming. We found that this interaction is mediated through the interplay of the CHD1L macro‐domain and the PAR moiety of PARylated‐PARP1. Chromatin immunoprecipitation assays demonstrated the co‐occupancy of CHD1L and PARP1 at Pou5f1, Nanog, and Esrrb pluripotency loci. Knockdown of CHD1L significantly blocked the binding activity of PARP1 at pluripotency loci and inhibited the efficiency of PARP1‐driven reprogramming. Notably, we found that CHD1L‐promoted reprogramming requires both a PARP1‐interacting domain and DNA helicase activity, partly contributing to the chromatin‐remodeling states of pluripotency loci. Taken together, these results identify CHD1L as a key chromatin remodeler involved in PARP1/PARylation‐regulated early‐stage reprogramming and pluripotency in stem cells. Stem Cells
2015;33:2961–2972
“…Poly(ADP-ribosyl)ation is a post-translational modification of proteins mediated by one of the 17 members of the poly(ADP-ribose) polymerases (PARP; Amé et al, 2004;Schreiber et al, 2006). PARP-1, the founding member of the PARP family, is a molecular sensor of DNA breaks, playing a key role in the spatial and temporal organization of break repair through the local synthesis of poly(ADP-ribose) (PAR) at damaged sites.…”
The macroPARPs Parp-9 and Parp-14 are macro domain containing poly(ADP-ribose) polymerases involved in transcriptional regulation in response to immunoregulatory cytokines. Their genes reside in the same locus (16B3), and the Parp-9 gene lies head-to-head and shares its promoter with the gene encoding its partner, Bbap. Here, we provide a detailed analysis of Parp-9, Parp-14, and Bbap expression during mouse development and adulthood. Parp-9 is developmentally regulated, and prominently expressed in the thymus and specific regions of the brain and gut. In adults, highest expression is maintained in the thymus and intestine. Parp-14 is more weakly expressed, mainly in the thymus during development and in adulthood. In addition, we show that Bbap is essentially coexpressed with Parp-9 during development and in adult mouse. However, the different levels of their transcripts detected in the developing brain and gut suggest that Bbap and Parp-9 display both common and independent tissue-specific regulations.
“…Although rasfonin decreased LC3-II levels at 2-h time point, yet, CQ was able to prevent LC3-II from degradation (Grumati et al 2010; Klionsky et al 2012), suggesting an enhanced autophagic flux (Figure 3(d)). Meanwhile, NAC also blocked the cleavage of PARP-1 (Figure 3(e)), a hallmark of apoptosis (Amé et al 2004), and indicating that ROS is also involved in rasfonin-induced apoptotic process. 10.1080/21501203.2016.1170073-F0003Figure 3.Rasfonin stimulates autophagy and apoptosis through rapidly ROS generation.…”
Rasfonin is a fungal secondary metabolite demonstrating with antitumour effects. Reactive oxygen species (ROS) are formed as a natural by-product of the normal metabolism of oxygen and have important roles in cell signalling and homeostasis. Studies reported that many fungal secondary metabolites activated either autophagy or apoptosis through ROS generation. In former study, we revealed that rasfonin induced both autophagy and apoptosis, however, whether it promoted aforementioned processes via upregulation of ROS generation remains explored. In the current work, we demonstrated that rasfonin induced autophagy and apoptosis concomitant with a dramatically ROS production. N-Acetylcysteine (NAC), an often used ROS inhibitor, decreased both autophagic flux and caspase-dependent apoptosis by rasfonin. Flow cytometry analysis revealed NAC was able to reduce rasfonin-dependent apoptosis and necrosis. In methanethiosulfonate (MTS) assay, we observed that NAC significantly blocked rasfonin-induced cell viability loss. In addition, we found that rasfonin increased the phosphorylation of c-Jun NH2-terminal kinase (JNK), which was inhibited by NAC. SP600125, an inhibitor of JNK, reduced rasfonin-dependent autophagic flux and apoptosis. Moreover, we demonstrated that rasfonin inhibited the phosphorylation of both 4E-binding protein 1 (4E-BP1) and S6 kinase 1 (S6K1), two main substrates of mammalian target of rapamycin (mTOR). Collectively, rasfonin activated autophagy and apoptosis through upregulation of ROS/JNK signalling.
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