RNA can catalyze and participate in many chemical and biochemical reactions.Non-coding RNAs(ncRNA)can regulate cellular transcription and translation reactions.We have demonstrated biochemically that RNA can also inte...RNA can catalyze and participate in many chemical and biochemical reactions.Non-coding RNAs(ncRNA)can regulate cellular transcription and translation reactions.We have demonstrated biochemically that RNA can also interfere with DNA polymerization via transforming DNA polymerase into deoxyribonucleoside triphosphate diphosphatase(dNTP-DPase).RNA,even with six nucleotides,can transform DNA polymerase into dNTP-DPase,and the dNTP-DPase activity causes the hydrolysis of dNTPs into dNMPs and pyrophosphate.Moreover,we have found that DNA polymerases from several families generally have similar RNA-dependent dNTP-DPase activity.We have also observed that in the presence of RNA,when the dNTP concentrations are relatively low,and that the dNTP-DPase activity can deplete dNTPs and interfere with DNA polymerization.Thus,we have discovered for the first time that in the presence of RNA,DNA polymerase can behave as a diphosphatase and inhibit DNA synthesis when dNTP quantity is low.These in vitro observations might imply a plausible role of RNA in vivo,such as suppressing DNA synthesis during a resting phase(G0)of the cell cycle,when RNA quantity is high and dNTP quantity is low.展开更多
Mammalian AlkB homologue 2(ALKBH2)is the primary housekeeping DNA demethylase,effectively repairing endogenously formed methylated lesions in double-stranded DNA.Our previous studies demonstrated that a hydrophobicβ-...Mammalian AlkB homologue 2(ALKBH2)is the primary housekeeping DNA demethylase,effectively repairing endogenously formed methylated lesions in double-stranded DNA.Our previous studies demonstrated that a hydrophobicβ-hairpin motif of ALKBH2 could play crucial roles in base-pair stability interrogation and damaged base flipping.Using chemical cross-linking strategy,we obtained two crystal structures of human ALKBH2 mutant bound to duplex DNA.The structural analysis suggests that theβ-hairpin motif is flexible in conformation and is likely to slide along the DNA duplex in local regions to search for damaged base.This study provides a new mechanistic insight into DNA damage detection by ALKBH2.展开更多
基金financially supported by the Georgia Cancer Coalition(GCC)Distinguished Cancer Clinicians and Scientists,USA NSF(IIP-1340153)and NIH(R01GM095881)
文摘RNA can catalyze and participate in many chemical and biochemical reactions.Non-coding RNAs(ncRNA)can regulate cellular transcription and translation reactions.We have demonstrated biochemically that RNA can also interfere with DNA polymerization via transforming DNA polymerase into deoxyribonucleoside triphosphate diphosphatase(dNTP-DPase).RNA,even with six nucleotides,can transform DNA polymerase into dNTP-DPase,and the dNTP-DPase activity causes the hydrolysis of dNTPs into dNMPs and pyrophosphate.Moreover,we have found that DNA polymerases from several families generally have similar RNA-dependent dNTP-DPase activity.We have also observed that in the presence of RNA,when the dNTP concentrations are relatively low,and that the dNTP-DPase activity can deplete dNTPs and interfere with DNA polymerization.Thus,we have discovered for the first time that in the presence of RNA,DNA polymerase can behave as a diphosphatase and inhibit DNA synthesis when dNTP quantity is low.These in vitro observations might imply a plausible role of RNA in vivo,such as suppressing DNA synthesis during a resting phase(G0)of the cell cycle,when RNA quantity is high and dNTP quantity is low.
基金financially supported by the Hundred Talents Program of the Chinese Academy of Sciences,Key Project of Chinese National Programs for Fundamental Research and Development(2009CB918502)
文摘Mammalian AlkB homologue 2(ALKBH2)is the primary housekeeping DNA demethylase,effectively repairing endogenously formed methylated lesions in double-stranded DNA.Our previous studies demonstrated that a hydrophobicβ-hairpin motif of ALKBH2 could play crucial roles in base-pair stability interrogation and damaged base flipping.Using chemical cross-linking strategy,we obtained two crystal structures of human ALKBH2 mutant bound to duplex DNA.The structural analysis suggests that theβ-hairpin motif is flexible in conformation and is likely to slide along the DNA duplex in local regions to search for damaged base.This study provides a new mechanistic insight into DNA damage detection by ALKBH2.
