Perrotta A T, Been M D
Department of Biochemistry, Duke University Medical Center, Durham, NC 27710.
Nucleic Acids Res. 1990 Dec 11;18(23):6821-7. doi: 10.1093/nar/18.23.6821.
The sequence requirements for self-cleavage of hepatitis delta virus genomic RNA were examined using precursor RNAs which were labeled at either the 5' or 3' ends and progressively deleted from the unlabeled end. In the presence of 50% formamide, which enhances self-cleavage in 2 mM MgCl2 at 37 degrees C, 84 nucleotides (nt) 3' of the break site were required. In the absence of formamide the minimum was reduced to 82 nt. Under both sets of conditions, precursors with 1 nt 5' to the break site cleaved. These results allowed two condition-dependent minimal domains for self-cleavage to be defined. However, in the absence of formamide, sequences flanking the minimal domain inhibited cleavage, possibly through involvement in the formation of non-cleaving structures. These data are consistent with the idea that cleavage in vivo could be regulated by alternative RNA structures.
利用在5'或3'端进行标记并从未标记端逐步缺失的前体RNA，研究了丁型肝炎病毒基因组RNA自我切割的序列要求。在50%甲酰胺存在的情况下，甲酰胺可增强2 mM MgCl2在37℃时的自我切割，切割位点3'端需要84个核苷酸（nt）。在没有甲酰胺的情况下，最小值降至82 nt。在两组条件下，切割位点5'端有1 nt的前体均可切割。这些结果确定了两个依赖条件的自我切割最小结构域。然而，在没有甲酰胺的情况下，最小结构域两侧的序列会抑制切割，这可能是通过参与非切割结构的形成来实现的。这些数据与体内切割可由替代性RNA结构调控的观点一致。
