Identification and Visualization of the Dimerization Initiation Site of the Prototype Lentivirus, Maedi Visna Virus: A Potential GACG Tetraloop Displays Structural Homology with the 详细信息    查看全文

• 作者：Tom P. Monie ; Jane S. Greatorex ; Laura Maynard-Smith ; Ben D. C. Hook ; Naomi Bishop ; Lucy P. Beales ; and Andrew M. L. Lever
• 刊名：Biochemistry
• 出版年：2005
• 出版时间：January 11, 2005
• 年：2005
• 卷：44
• 期：1
• 页码：294 - 302
• 全文大小：549K
• 年卷期：v.44,no.1(January 11, 2005)
• ISSN：1520-4995

文摘

Dimerization of retroviral genomic RNA is essential for efficient viral replication and is mediatedby structural interactions between identical RNA motifs in the viral leader region. We have visualized, byelectron microscopy, RNA dimers formed from the leader region of the prototype lentivirus, maedi visnavirus. Characterization by in vitro assays of the domains responsible for this interaction has identified a20 nucleotide sequence that functions as the core dimerization initiation site. This region is predicted toform a GACG tetraloop and therefore differs significantly from the kissing loop palindromes utilized toinitiate dimerization in primate lentiviruses. The motif is strongly conserved across the ovine and caprinelentiviruses, implying a critical functional role. Furthermore, the proposed GACG tetraloop exhibits markedstructural homology with similar structural motifs present in the leader regions of the - and -retroviruses,and the maedi visna virus dimer linkage region is capable of forming heterodimeric species with theMoloney murine leukemia virus domain. This may be indicative of commonality of origin of the twoviruses or convergent evolution.