Haseloff J, Gerlach W L
CSIRO Division of Plant Industry, Canberra, Australia.
Gene. 1989 Oct 15;82(1):43-52. doi: 10.1016/0378-1119(89)90028-0.
The satellite RNA of tobacco ringspot virus (sTobRV) undergoes self-catalysed cleavage during replication. A plasmid for in vitro expression of sTobRV has been constructed and used to obtain a library of mutagenized sTobRV sequences. Screening of these mutants has allowed precise definition of the sequences required for (+) and (-) strand cleavage. The sequences and RNA structures associated with cleavage of each strand differ markedly. Cleavage of the (+) strand requires those sequences flanking the site for cleavage to form a 'hammerhead' domain, similar to those found in other satellite and viroid RNA. In contrast, cleavage of the (-) strand requires only a small region of 12 nucleotides (nt) at the site of cleavage, and a sequence of 55 nt positioned elsewhere in the molecule. Comparison with a closely related satellite suggests that a novel RNA structure may be involved in (-) strand cleavage.
烟草环斑病毒的卫星RNA（sTobRV）在复制过程中会发生自我催化切割。已构建了一个用于体外表达sTobRV的质粒，并用于获得诱变的sTobRV序列文库。对这些突变体的筛选使得能够精确界定正链和负链切割所需的序列。与每条链切割相关的序列和RNA结构明显不同。正链切割需要切割位点两侧的那些序列形成一个“锤头”结构域，类似于在其他卫星RNA和类病毒RNA中发现的结构域。相比之下，负链切割仅需要切割位点处12个核苷酸（nt）的小区域以及位于分子其他位置的55 nt序列。与一种密切相关的卫星RNA比较表明，一种新的RNA结构可能参与负链切割。
