Flynn Jessica A, Telesnitsky Alice
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620, USA.
Virology. 2006 Jan 20;344(2):391-400. doi: 10.1016/j.virol.2005.09.002. Epub 2005 Oct 10.
Two genetically distinct retroviral RNAs can be co-packaged if the RNAs are co-expressed in virion producing cells. For Moloney murine leukemia virus (MLV), co-packaged RNAs are not randomly selected from among all packaging-competent RNAs, but instead primarily associate as homodimers. Here, we tested the hypothesis that the distance between proviral templates might hinder RNA heterodimerization, thus generating the observed preferential homodimerization of co-expressed MLV RNAs. To do this, two genetically distinct RNAs were co-expressed from a single locus and the proportions of hetero- and homodimeric virion RNAs were determined. Unlike RNAs transcribed from two different templates, RNAs transcribed from a single locus dimerized at random. Additionally, in vitro transcription experiments suggested that MLV RNA dimerization can occur more efficiently for longer RNAs during transcription than post-synthesis. Together, these findings show that MLV RNA dimer-partner selection likely occurs either co-transcriptionally or within a pool of transcripts near the proviral template.
如果两种基因不同的逆转录病毒RNA在病毒产生细胞中共同表达，它们可以被共同包装。对于莫洛尼鼠白血病病毒（MLV），共同包装的RNA不是从所有具有包装能力的RNA中随机选择的，而是主要以同二聚体形式存在。在这里，我们测试了一个假设，即原病毒模板之间的距离可能会阻碍RNA异二聚体化，从而导致观察到的共同表达的MLV RNA优先同二聚体化。为此，从单个位点共同表达两种基因不同的RNA，并确定异二聚体和同二聚体病毒体RNA的比例。与从两个不同模板转录的RNA不同，从单个位点转录的RNA随机二聚化。此外，体外转录实验表明，在转录过程中，较长的MLV RNA比合成后更有效地发生二聚化。这些发现共同表明，MLV RNA二聚体伙伴的选择可能发生在转录过程中或原病毒模板附近的转录本池中。
