烟酰胺腺嘌呤二核苷酸（NAD+）、ADP-核糖基化与通透化哺乳动物细胞中的转录
NAD+, ADP-ribosylation and transcription in permeabilized mammalian cells.
作者信息
Walker J, Pearson C K
出版信息
Biochem J. 1981 Dec 1;199(3):813-7. doi: 10.1042/bj1990813.
When permeabilized hamster fibroblasts were incubated with 4 mM-NAD+, the substrate for poly(ADP-ribose) polymerase, RNA polymerase I activity was inhibited by about 85%. This inhibition was not relieved by prior incubation of cells with 3-aminobenzamide, a potent inhibitor of the poly(ADP-ribose) polymerase. Digestion of cells with pancreatic deoxyribonuclease I resulted in the inhibition of RNA polymerase I by 80% and the activation of poly(ADP-ribose) polymerase by up to 300%; prior incubation with 3-aminobenzamide did not prevent the inhibition of the RNA polymerase activity. No radioactivity was found associated with RNA polymerase I during later stages of purification of this enzyme from permeabilized cells previously incubated with [14C]NAD+. The inhibitory effect of NAD+ on RNA polymerase I was not specific for NAD+, as other small, negatively charged molecules with a nuclear location also inhibited the enzyme. The results do not support the concept of a role for ADP-ribosylation in transcription catalysed by RNA polymerase I.
当用4 mM-NAD⁺（聚（ADP-核糖）聚合酶的底物）孵育通透化的仓鼠成纤维细胞时，RNA聚合酶I的活性被抑制了约85%。用3-氨基苯甲酰胺（一种聚（ADP-核糖）聚合酶的有效抑制剂）预先孵育细胞并不能解除这种抑制。用胰脱氧核糖核酸酶I消化细胞导致RNA聚合酶I被抑制80%，聚（ADP-核糖）聚合酶被激活高达300%；用3-氨基苯甲酰胺预先孵育并不能阻止RNA聚合酶活性的抑制。在从先前用[¹⁴C]NAD⁺孵育的通透化细胞中纯化该酶的后期阶段，未发现与RNA聚合酶I相关的放射性。NAD⁺对RNA聚合酶I的抑制作用并非NAD⁺所特有，因为其他带负电荷且定位于细胞核的小分子也能抑制该酶。这些结果不支持ADP-核糖基化在RNA聚合酶I催化的转录中起作用这一概念。
Zotero 插件