Davies C, Sheldon C C, Symons R H
Department of Biochemistry, University of Adelaide, Australia.
Nucleic Acids Res. 1991 Apr 25;19(8):1893-8. doi: 10.1093/nar/19.8.1893.
The plus and minus RNAs of the 247 nt avocado sunblotch viroid (ASBV) undergo site specific RNA self-cleavage reactions in vitro. As with several other self-cleaving RNAs, we proposed hammerhead secondary structures for the sequence around the site of self-cleavage of both RNAs. We have shown previously that, during transcription of a dimeric plus ASBV RNA, a double-hammerhead structure formed and was necessary for self-cleavage. Here, we show that the purified full-length dimeric plus RNA, when incubated under our standard self-cleavage conditions, also self-cleaved by a double-hammerhead structure. In contrast, a dimeric minus ASBV RNA self-cleaved by a double-hammerhead structure during transcription, but by a single-hammerhead structure after purification. This illustrates the importance of the pathway of folding of the RNA in determining which active self-cleaving structure is formed.
247个核苷酸的鳄梨日斑类病毒（ASBV）的正链和负链RNA在体外会发生位点特异性的RNA自我切割反应。与其他几种自我切割RNA一样，我们为这两种RNA自我切割位点周围的序列提出了锤头状二级结构。我们之前已经表明，在二聚体正链ASBV RNA转录过程中，会形成双锤头结构，且该结构对于自我切割是必需的。在此，我们表明，纯化的全长二聚体正链RNA在我们的标准自我切割条件下孵育时，也会通过双锤头结构进行自我切割。相比之下，二聚体负链ASBV RNA在转录过程中通过双锤头结构进行自我切割，但在纯化后则通过单锤头结构进行自我切割。这说明了RNA折叠途径在决定形成哪种活性自我切割结构方面的重要性。
