Kissing-loop model of HIV-1 genome dimerization: HTV-1 RNAs can assume alternative dimeric forms, and all sequences upstream or downstream of hairpin 248-271 are dispensable for dimer formation
Kissing-loop model of HIV-1 genome dimerization: HTV-1 RNAs can assume alternative dimeric forms, and all sequences upstream or downstream of hairpin 248-271 are dispensable for dimer formation
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DOI：
10.1021/bi951838f
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发表时间：
1996-02-06
期刊：
影响因子：
2.9
通讯作者：
Jette, L
中科院分区：
文献类型：
--
作者：
Laughrea, M;Jette, L
所有逆转录病毒的基因组由两个相同的RNA在其5'端附近非共价连接组成。基因组RNA的二聚化被认为调节逆转录病毒生命周期中的几个步骤，如重组、翻译和折叠。HIV-1基因组二聚化的吻环模型[Laughrea，M.，& Jette，L.（1994）Biochemistry 33，13464-13474; Skripkin等人（1994）Proc.Natl. Acad. Sci. U.S.A.91，4945-4949]假定HIV-1基因组的248-270区域通过形成发夹并通过环-环相互作用引发二聚化而为完整的。或至少HIV-1 RNA的核心二聚化结构域。在此，我们通过巢式缺失分析表明HIV-1二聚化结构域的3'边界紧邻发夹248-270的下游，并且分离的区域248-271至少与较长的RNA一样容易二聚化。在含有发夹248-270的各种HIV-1（Lai）RNA转录物中，所有转录物都形成两种类型的二聚体，这在接吻环模型中是隐含的。高稳定性的二聚体抵抗半饱和条件，而低稳定性的二聚体不能，这与模型一致。在生理温度下，通常形成低稳定性二聚体，好像没有核衣壳蛋白的二聚化对应于环-环相互作用，而没有从链内氢键转换到链间氢键。我们的研究结果表明，3' DLS（紧邻5'剪接点3'的序列，最初被认为是HIV-1基因组的二聚化结构域）和相邻核苷酸对于在低和高离子强度下HIV-1（Lai）RNA的有效二聚化不是必需的。发夹248-270的上游存在另一种“DLS样”序列，我们将其命名为5' DLS：与分离的3' DLS一样，分离的5' DLS形成明显的非生理结构，其在高离子强度下可以基本上变成二聚体。
The genome of all retroviruses consists of two identical RNAs noncovalently linked near their 5' end. Dimerization of genomic RNA is thought to modulate several steps in the retroviral life cycle, such as recombination, translation, and encapsidation. The kissing-loop model of HIV-1 genome dimerization [Laughrea, M., & Jette, L. (1994) Biochemistry 33, 13464-13474; Skripkin et al. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 4945-4949] posits that the 248-270 region of the HIV-1 genome, by forming a hairpin and initiating dimerization through a loop-loop interaction, is the full. or at least the core dimerization domain of HIV-1 RNA. Here, we show by nested deletion analysis that the 3' boundary of the HIV-1 dimerization domain is immediately downstream of hairpin 248-270 and that the isolated region 248-271 dimerizes at least as readily as longer RNAs. Among various HIV-1(Lai) RNA transcripts containing hairpin 248-270, all form two types of dimer, as is implicit in the kissing-loop model. The high-stability dimer resists semidenaturing conditions and the low-stability dimer cannot, which is consistent with the model. At physiological temperatures, low-stability dimers are usually formed, as if dimerization without nucleocapsid proteins corresponded to loop-loop interaction without switching from intra- to interstrand hydrogen bonding. Our results show that the 3' DLS (a sequence immediately 3' from the 5' splice junction and originally thought to be the dimerization domain of the HIV-I genome) and adjacent nucleotides are not necessary for efficient dimerization of HIV-1(Lai) RNA at low and high ionic strength. Upstream of hairpin 248-270 exists another ''DLS-like'' sequence that we name 5' DLS: like the isolated 3' DLS, the isolated 5' DLS forms an apparently nonphysiological structure that can become substantially dimeric at high ionic strength.