Kletzien R F
Biochem J. 1980 Nov 15;192(2):753-9. doi: 10.1042/bj1920753.
The addition of 3'-deoxyadenosine (cordycepin) to cells in culture results in the inhibition of the appearance of mRNA in the cytoplasm through a mechanism thought to involve the inhibition of polyadenylate synthesis. I studied the effect of 3'-deoxyadenosine triphosphate, the physiologically active form of 3'-deoxyadenosine, on RNA release from isolated nuclei. Nuclei were isolated from baby-hamster kidney (BHK) fibroblasts that had been given a short pulse of radioactive uridine or adenosine in the presence of a low concentration of actinomycin D before harvest. RNA release from the isolated nuclei under the appropriate incubation conditions was time-, temperature- and ATP-dependent. 3'-Deoxyadenosine triphosphate inhibited RNA release from the isolated nuclei. However, RNA that was restricted to the nuclei during incubation with the drug could be chased out of the nuclei if the incubation medium was replaced with medium containing only ATP. The chased poly(A)+ (polyadenylated) RNA had shortened poly(A) tracts, indicating that poly(A)+ RNA with shortened poly(A) tracts can be transported out of the nucleus. An experiment was designed to test the effect of 3'-deoxyadenosine triphosphate on the release of poly(A)+ RNA at drug concentrations which caused 33 or 64% inhibition of RNA release. The release of poly(A)+ RNA and poly(A)- RNA (not polyadenylated) was equally inhibited by the drug. Thus, although 3'-deoxyadenosine triphosphate does inhibit release of RNA from the nucleus, it would appear that the drug does so through a mechanism independent of the inhibition of polyadenylation. The process that is inhibited must be one that is common to both poly(A)+ and poly(A)- RNA. The possibility that 3'-deoxyadenosine triphosphate inhibits a reaction at the nuclear membrane or nuclear pore complex is considered.
在培养的细胞中添加3'-脱氧腺苷（虫草素）会导致细胞质中mRNA的出现受到抑制，其机制被认为涉及对多聚腺苷酸合成的抑制。我研究了3'-脱氧腺苷三磷酸（3'-脱氧腺苷的生理活性形式）对从分离的细胞核中释放RNA的影响。细胞核是从幼年仓鼠肾（BHK）成纤维细胞中分离出来的，这些细胞在收获前于低浓度放线菌素D存在的情况下短暂脉冲标记放射性尿苷或腺苷。在适当的孵育条件下，从分离的细胞核中释放RNA是时间、温度和ATP依赖性的。3'-脱氧腺苷三磷酸抑制了从分离的细胞核中释放RNA。然而，如果将孵育培养基换成仅含ATP的培养基，那么在与该药物孵育期间局限于细胞核内的RNA可以被“追赶”出细胞核。被“追赶”出的多聚腺苷酸（poly(A)+）RNA的多聚腺苷酸尾缩短了，这表明多聚腺苷酸尾缩短的poly(A)+ RNA可以被转运出细胞核。设计了一个实验来测试在导致RNA释放受到33%或64%抑制的药物浓度下3'-脱氧腺苷三磷酸对poly(A)+ RNA释放的影响。该药物对poly(A)+ RNA和非多聚腺苷酸化的poly(A)- RNA的释放具有同等程度的抑制作用。因此，尽管3'-脱氧腺苷三磷酸确实抑制了RNA从细胞核的释放，但该药物似乎是通过一种独立于对多聚腺苷酸化抑制的机制来实现的。被抑制的过程必定是poly(A)+和poly(A)- RNA共有的一个过程。考虑了3'-脱氧腺苷三磷酸抑制核膜或核孔复合体处反应的可能性。
