College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
Infect Genet Evol. 2012 Oct;12(7):1452-7. doi: 10.1016/j.meegid.2012.05.006. Epub 2012 Jun 1.
Compound microsatellites consist of two or more individual microsatellites, and may originate from dynamic mutations or imperfection of microsatellites. Previous studies have found microsatellites were present in 81 completed Human Immunodeficiency Virus Type 1 (HIV-1) genomes, suggesting compound microsatellites may exist in viral genomes. However, up to now, compound microsatellites have not been analyzed in any viral genomes. We identified and characterized 238 compound microsatellites in 81 completed HIV-1 genomes. About 0-24.24% of all microsatellites could be categorized as compound microsatellites. Compound microsatellite distribution is very different in two aspects between diverse HIV-1 genomes. First, the number and motifs of compound microsatellites are variable between surveyed genomes. Second, the relative abundance and relative density of compound microsatellites exhibit very significant differences between these surveyed genomes, respectively. The relative abundance and relative density of compound microsatellites were weakly correlated with genome size and microsatellite density. We observed a more dynamic picture of compound microsatellites than previously reported in eukaryotes. This might be attributed to the lack of proofreading in HIV-1 genomes, as it has been demonstrated that the loss of polymerase proofreading activity can greatly enhance the mutation rate of microsatellites.
复合微卫星由两个或多个独立的微卫星组成，可能来源于微卫星的动态突变或不完美。先前的研究发现，81 个已完成的人类免疫缺陷病毒 1 型（HIV-1）基因组中存在微卫星，这表明病毒基因组中可能存在复合微卫星。然而，到目前为止，还没有在任何病毒基因组中分析过复合微卫星。我们在 81 个已完成的 HIV-1 基因组中鉴定和描述了 238 个复合微卫星。大约 0-24.24%的所有微卫星可以归类为复合微卫星。在不同的 HIV-1 基因组中，复合微卫星的分布在两个方面存在很大差异。首先，调查基因组之间复合微卫星的数量和基序是可变的。其次，这些调查基因组之间复合微卫星的相对丰度和相对密度存在非常显著的差异。复合微卫星的相对丰度和相对密度与基因组大小和微卫星密度呈弱相关。我们观察到的复合微卫星比以前在真核生物中报道的更为动态。这可能归因于 HIV-1 基因组中缺乏校对，因为已经证明聚合酶校对活性的丧失可以大大提高微卫星的突变率。
