Kang H
Kumho Life and Environmental Science Laboratory, Korea Kumho Petrochemical Co. Ltd., Kwangju, South Korea.
Biochim Biophys Acta. 1998 Apr 1;1397(1):73-8. doi: 10.1016/s0167-4781(98)00004-9.
Programmed ribosomal frameshifting in viral messenger RNA occurs in response to neighboring sequence elements consisting of: a frameshift site, a spacer, and a downstream enhancer sequence. In human immunodeficiency virus type 1 (HIV-1) mRNA, this sequence element has a potential to form either a stem-loop or a pseudoknot structure. Based on many mutational studies, the stem-loop structure has been proposed for the downstream enhancer region of the HIV-1 mRNA. This stimulatory stem-loop structure is separated from the shift site by a spacer of seven nucleotides. In contrast, a recent report has proposed an alternative model in which the bases in the spacer sequence form a pseudoknot structure as the downstream enhancer sequence [Du et al., Biochemistry 35 (1996) 4187-4198.]. Using UV melting and enzymatic mapping analyses, we have investigated the conformation of the sequence region involved in ribosomal frameshifting in HIV-1. Our S1, V1, and T1 endonuclease mappings, together with UV melting analysis, clearly indicate that this sequence element of the HIV-1 mRNA frameshift site forms a stem-loop structure, not a pseudoknot structure. This finding further supports the stem-loop structure proposed by many mutational studies for the downstream enhancer sequence of the HIV-1 mRNA.
一个移码位点、一个间隔区和一个下游增强子序列。在1型人类免疫缺陷病毒（HIV-1）信使核糖核酸中，该序列元件有可能形成茎环结构或假结结构。基于许多突变研究，有人提出HIV-1信使核糖核酸下游增强子区域存在茎环结构。这种刺激性茎环结构与移码位点之间由七个核苷酸的间隔区分开。相比之下，最近有一份报告提出了另一种模型，即间隔区序列中的碱基与下游增强子序列一起形成假结结构[Du等人，《生物化学》35(1996)4187 - 4198]。通过紫外熔解和酶切图谱分析，我们研究了HIV-1中参与核糖体移码的序列区域的构象。我们的S1、V1和T1核酸内切酶图谱分析以及紫外熔解分析清楚地表明，HIV-1信使核糖核酸移码位点的这个序列元件形成的是茎环结构，而非假结结构。这一发现进一步支持了许多突变研究提出的关于HIV-1信使核糖核酸下游增强子序列的茎环结构。
