DNA-activated protein kinase functions in a newly observed S phase checkpoint that links histone mRNA abundance with DNA replication.
DNA and histone synthesis are coupled and ongoing replication is required to maintain histone gene expression. Here, we expose S phase-arrested cells to the kinase inhibitors caffeine and LY294002. This uncouples DNA replication from histone messenger RNA (mRNA) abundance, altering the efficiency of replication stress-induced histone mRNA down-regulation. Interference with caffeine-sensitive checkpoint kinases ataxia telangiectasia and Rad3 related (ATR)/ataxia telangiectasia mutated (ATM) does not affect histone mRNA down- regulation, which indicates that ATR/ATM alone cannot account for such coupling. LY294002 potentiates caffeine's ability to uncouple histone mRNA stabilization from replication only in cells containing functional DNA-activated protein kinase (DNA-PK), which indicates that DNA-PK is the target of LY294002. DNA-PK is activated during replication stress and DNA-PK signaling is enhanced when ATR/ATM signaling is abrogated. Histone mRNA decay does not require Chk1/Chk2. Replication stress induces phosphorylation of UPF1 but not hairpin[corrected]-binding protein/stem-loop binding protein at S/TQ sites, which are preferred substrate recognition motifs of phosphatidylinositol 3-kinase-like kinases, which indicates that histone mRNA stability may be directly controlled by ATR/ATM- and DNA-PK-mediated phosphorylation of UPF1.
D064007:Ataxia Telangiectasia Mutated Proteins; D002110:Caffeine / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D045744:Cell Line, Tumor; D002867:Chromones / Q000494:pharmacology; D004261:DNA Replication / Q000235:genetics*; D051747:DNA-Activated Protein Kinase / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018816:Genes, cdc / Q000502:physiology*; D006367:HeLa Cells; D006657:Histones / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D020365:RNA Helicases; D020871:RNA Stability / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D016196:S Phase / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics
D018797:Cell Cycle Proteins; D002867:Chromones; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D006657:Histones; D009025:Morpholines; D012333:RNA, Messenger; D015534:Trans-Activators; D025521:Tumor Suppressor Proteins; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D002110:Caffeine; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases; D020365:RNA Helicases; C101828:UPF1 protein, human