Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
Curr Biol. 2012 Jan 24;22(2):166-70. doi: 10.1016/j.cub.2011.11.060. Epub 2011 Dec 28.
Like protein-coding genes, loci that produce microRNAs (miRNAs) are generally considered to be under purifying selection, consistent with miRNA polymorphisms being able to cause disease. Nevertheless, it has been hypothesized that variation in miRNA genes may contribute to phenotypic diversity. Here we demonstrate that a naturally occurring polymorphism in the MIR164A gene affects leaf shape and shoot architecture in Arabidopsis thaliana, with the effects being modified by additional loci in the genome. A single base pair substitution in the miRNA complementary sequence alters the predicted stability of the miRNA:miRNA(∗) duplex. It thereby greatly reduces miRNA accumulation, probably because it interferes with precursor processing. We demonstrate that this is not a rare exception and that natural strains of Arabidopsis thaliana harbor dozens of similar polymorphisms that affect processing of a wide range of miRNA precursors. Our results suggest that natural variation in miRNA biogenesis resulting from cis mutations is a common contributor to phenotypic variation in plants.
与编码蛋白质的基因类似，产生 microRNAs (miRNAs) 的基因座通常被认为受到纯化选择的限制，这与 miRNA 多态性能够导致疾病的观点是一致的。然而，有人假设 miRNA 基因的变异可能有助于表型多样性。在这里，我们证明了 MIR164A 基因中的一个自然发生的多态性会影响拟南芥的叶片形状和茎结构，而基因组中的其他基因座会影响这些效应。miRNA 互补序列中的单个碱基替换会改变 miRNA:miRNA(∗)双链的预测稳定性。因此，它大大降低了 miRNA 的积累，可能是因为它干扰了前体处理。我们证明这不是一个罕见的例外，拟南芥的天然品系中存在数十种类似的多态性，这些多态性会影响广泛的 miRNA 前体的加工。我们的结果表明，由于顺式突变导致的 miRNA 生物发生的自然变异是植物表型变异的一个常见原因。
