Department of Biotechnology, Kakatiya University, Warangal, Telangana 506009, India.
Department of Biotechnology, Kakatiya University, Warangal, Telangana 506009, India.
Int J Biol Macromol. 2022 Oct 31;219:1261-1271. doi: 10.1016/j.ijbiomac.2022.08.182. Epub 2022 Aug 31.
Epigenetic changes are the heritable modifications in genes without altering DNA sequences. The epigenetic changes occur in the plant genomes to regulate gene expression patterns, which were used to regulate different biological processes, including coping various environmental stresses. These changes, including DNA methylation, non-coding RNA regulation, and histone modification, play a vital role in the transcription and translation processes to regulate gene expression. Gene engineering for the development of stress-tolerant crops via the DNA methylation pathway initially needs a proper selection of genes and its promoter. Manipulating epigenetics requires genetic engineering tools such as Zinc finger nucleases (ZFN), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas). However, CRISPR/Cas9 mediated epigenetic editing refers to transcriptional reprogramming at the targeted sites using epigenetic enzymes fused with decatalytical Cas9 (dCas9). This review focused on the different epigenetic mechanisms in plants and their potential contribution to developing epigenetic tools. The dCas9 endonuclease tethered with transcriptional repressor or activator domain leads to CRISPR inhibitor (CRISPRi) or activator (CRISPRa) for regulating gene expression. The dCas9 has been successfully fused with other various effector domains for constructing epigenetic tools, including the DNA methyltransferase 3A (DNMT3A), or the DNA demethylase TET. Multiple efforts have been made to improve epigenome editing in plants. Initially, incorporating SunTag into the dCas9-EpiEffector complex was used as an epigenetic tool; demethylation of target loci with dCas9-SunTag-TET1 futher increased its efficiency. Additionally, SunTag could also be fused with the dCas9-DNMT3A complex to augment CpG methylation at a targeted loci.
表观遗传变化是指基因的遗传修饰而不改变 DNA 序列。这些表观遗传变化发生在植物基因组中，以调节基因表达模式，这些模式被用来调节不同的生物过程，包括应对各种环境压力。这些变化包括 DNA 甲基化、非编码 RNA 调控和组蛋白修饰，它们在转录和翻译过程中发挥着重要作用，以调节基因表达。通过 DNA 甲基化途径对耐胁迫作物进行基因工程，最初需要对基因及其启动子进行适当的选择。操纵表观遗传需要遗传工程工具，如锌指核酸酶（ZFN）、转录激活因子样效应物核酸酶（TALENs）和成簇规律间隔短回文重复（CRISPR）/CRISPR 相关蛋白（Cas）。然而，CRISPR/Cas9 介导的表观遗传编辑是指使用与去催化 Cas9（dCas9）融合的表观遗传酶在靶向位点进行转录重编程。本综述重点介绍了植物中的不同表观遗传机制及其在开发表观遗传工具方面的潜在贡献。与转录抑制或激活结构域融合的 dCas9 内切酶导致 CRISPR 抑制剂（CRISPRi）或激活剂（CRISPRa），从而调节基因表达。dCas9 已成功与其他各种效应结构域融合，用于构建表观遗传工具，包括 DNA 甲基转移酶 3A（DNMT3A）或 DNA 去甲基化酶 TET。人们已经做出了多种努力来改善植物中的表观基因组编辑。最初，将 SunTag 整合到 dCas9-EpiEffector 复合物中用作表观遗传工具；dCas9-SunTag-TET1 进一步实现了靶位点的去甲基化，提高了其效率。此外，SunTag 还可以与 dCas9-DNMT3A 复合物融合，以增加靶向位点的 CpG 甲基化。
