Mendel Centre for Plant Genomics and Proteomics, Central European Institute for Technology (CEITEC), Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic.
Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic.
Int J Mol Sci. 2021 Jan 5;22(1):468. doi: 10.3390/ijms22010468.
Involvement of epigenetic mechanisms in the regulation of telomeres and transposable elements (TEs), genomic regions with the protective and potentially detrimental function, respectively, has been frequently studied. Here, we analyzed telomere lengths in plants of Columbia, Landsberg erecta and Wassilevskija ecotypes exposed repeatedly to the hypomethylation drug zebularine during germination. Shorter telomeres were detected in plants growing from seedlings germinated in the presence of zebularine with a progression in telomeric phenotype across generations, relatively high inter-individual variability, and diverse responses among ecotypes. Interestingly, the extent of telomere shortening in zebularine Columbia and Wassilevskija plants corresponded to the transcriptional activation of TEs, suggesting a correlated response of these genomic elements to the zebularine treatment. Changes in lengths of telomeres and levels of TE transcripts in leaves were not always correlated with a hypomethylation of cytosines located in these regions, indicating a cytosine methylation-independent level of their regulation. These observations, including differences among ecotypes together with distinct dynamics of the reversal of the disruption of telomere homeostasis and TEs transcriptional activation, reflect a complex involvement of epigenetic processes in the regulation of crucial genomic regions. Our results further demonstrate the ability of plant cells to cope with these changes without a critical loss of the genome stability.
在调节端粒和转座元件（TEs）的过程中，表观遗传机制的参与已被广泛研究。端粒是具有保护和潜在有害功能的基因组区域。在这里，我们分析了在发芽过程中反复暴露于去甲基化药物 zebularine 下的哥伦比亚、立耳 erecta 和 Wassilevskija 生态型植物的端粒长度。在 zebularine 存在下萌发的幼苗中生长的植物中检测到较短的端粒，随着世代的推移，端粒表型逐渐发展，个体间的变异性相对较高，不同生态型之间的反应也不同。有趣的是，zebularine 处理后 TE 的转录激活与哥伦比亚和 Wassilevskija 植物中端粒缩短的程度相对应，表明这些基因组元件对 zebularine 处理的反应具有相关性。在叶片中端粒长度和 TE 转录本水平的变化并不总是与这些区域中胞嘧啶的去甲基化相关，这表明它们的调节存在非依赖于胞嘧啶甲基化的水平。这些观察结果，包括生态型之间的差异以及端粒稳态和 TE 转录激活破坏的逆转动态的明显差异，反映了表观遗传过程在调节关键基因组区域方面的复杂参与。我们的结果进一步证明了植物细胞在不丧失基因组稳定性的情况下应对这些变化的能力。
