Kopec Piotr M, Karlowski Wojciech M
Department of Computational Biology, Faculty of Biology, Mickiewicz University in Poznań, Poznań, Poland.
Front Plant Sci. 2019 Jun 27;10:812. doi: 10.3389/fpls.2019.00812. eCollection 2019.
Intramolecular G-quadruplexes (G4s) are secondary structures that may form within G-rich stretches of nucleic acids. Although their presence has been associated with genomic instability and mutagenicity, recent reports suggest their involvement in regulation of diverse cellular events, including transcription and translation. The majority of data regarding G4s stems from mammalian and yeast studies, leaving the plant G4s almost unexplored. Using the publicly available and WGS data, we examined the single nucleotide variability of sequences predicted to form G4s (pG4s) structures. We focused our analysis on protein coding transcripts and compared the results to well-characterized data. We demonstrate that the overall high variability of pG4s is not uniform and differs between gene structural elements. Specifically, plant AUG-containing pG4s, located within 5'UTR/CDS junctions, are abundant and appear not to be affected by a higher frequency of sequence change, indicating their functional relevance. Furthermore, we show that substitutions lowering the probability of G4s' formation are preferred over neutral or stabilizing modifications.
分子内G-四链体（G4s）是可能在富含G的核酸片段内形成的二级结构。尽管它们的存在与基因组不稳定性和致突变性有关，但最近的报告表明它们参与了多种细胞事件的调控，包括转录和翻译。关于G4s的大多数数据来自哺乳动物和酵母研究，而植物G4s几乎未被探索。利用公开可用的全基因组测序（WGS）数据，我们研究了预测形成G4s（pG4s）结构的序列的单核苷酸变异性。我们将分析重点放在蛋白质编码转录本上，并将结果与特征明确的数据进行比较。我们证明，pG4s的总体高变异性并不均匀，并且在基因结构元件之间存在差异。具体而言，位于5'非翻译区（UTR）/编码序列（CDS）交界处的含植物AUG的pG4s丰富，并且似乎不受更高频率序列变化的影响，表明它们具有功能相关性。此外，我们表明，降低G4s形成概率的取代优于中性或稳定修饰。
