Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The histone variant mH2A is believed to be involved in transcriptional repression, but how it exerts its function remains elusive. By using chromatin immunoprecipitation and tandem affinity immunopurification of the mH2A1.1 nucleosome complex, we identified numerous genes with promoters containing mH2A1.1 nucleosomes. In particular, the promoters of the inducible Hsp70.1 and Hsp70.2 genes, but not that of the constitutively expressed Hsp70.8, were highly enriched in mH2A1.1. PARP-1 was identified as a part of the mH2A1.1 nucleosome complex and was found to be associated with the Hsp70.1 promoter. A specific interaction between mH2A1.1 and PARP-1 was demonstrated and found to be associated with inactivation of PARP-1 enzymatic activity. Heat shock released both mH2A1.1 and PARP-1 from the Hsp70.1 promoter and activated PARP-1 automodification activity. The data we present point to a novel mechanism for control of Hsp70.1 gene transcription. mH2A1.1 recruits PARP-1 to the promoter, thereby inactivating it. Upon heat shock, the Hsp70.1 promoter-bound PARP-1 is released to activate transcription through ADP-ribosylation of other Hsp70.1 promoter-bound proteins.
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PMID:The histone variant mH2A1.1 interferes with transcription by down-regulating PARP-1 enzymatic activity. 1715 48

Poly-ADP-ribosylation is a post-translational modification catalyzed by PARP enzymes with roles in transcription and chromatin biology. Here we show that distinct macrodomains, including those of histone macroH2A1.1, are recruited to sites of PARP1 activation induced by laser-generated DNA damage. Chemical PARP1 inhibitors, PARP1 knockdown and mutation of ADP-ribose-binding residues in macroH2A1.1 abrogate macrodomain recruitment. Notably, histone macroH2A1.1 senses PARP1 activation, transiently compacts chromatin, reduces the recruitment of DNA damage factor Ku70-Ku80 and alters gamma-H2AX patterns, whereas the splice variant macroH2A1.2, which is deficient in poly-ADP-ribose binding, does not mediate chromatin rearrangements upon PARP1 activation. The structure of the macroH2A1.1 macrodomain in complex with ADP-ribose establishes a poly-ADP-ribose cap-binding function and reveals conformational changes in the macrodomain upon ligand binding. We thus identify macrodomains as modules that directly sense PARP activation in vivo and establish macroH2A histones as dynamic regulators of chromatin plasticity.
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PMID:A macrodomain-containing histone rearranges chromatin upon sensing PARP1 activation. 1973 87