cis–trans Engineering: Advances and Perspectives on Customized Transcriptional Regulation in Plants

Abstract

Coordinated transcriptional control employing synthetic promoters and transcription factors (TFs) can be used to achieve customized regulation of gene expression in planta. Synthetic promoter technology has yielded a series of promoters with modified cis-regulatory elements that provide useful tools for efficient modulation of gene expression. In addition, the use of zinc fingers (ZFs), transcription activator-like effectors (TALEs), and catalytically inactive clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (dCas9) has made it feasible to engineer TFs that can produce targeted gene expression regulation; these approaches are particularly effective when artificial TFs are coupled with transcriptional activators or repressors. This review focuses on strategies used to engineer both promoters and TFs in the context of targeted transcriptional regulation. We also discuss the creation of synthetic inducible platforms, which can be used to impart stress tolerance to plants. We propose that combinatorial "cis-trans engineering" using a CRISPR-dCas9-based bipartite module could be used to regulate the expression of multiple target genes. This approach provides an attractive tool for introduction of specific qualitative traits into plants, thus enhancing their overall environmental adaptability.

Function and Mechanism of WRKY Transcription Factors in Abiotic Stress Responses of Plants

“…Transcription factors (TFs) are important regulators involved in the process of signal transduction and gene expression regulation under environmental stresses. TFs can be combined with cis-acting elements to regulate the transcriptional efficiency of target genes by inhibiting or enhancing their transcription [3,4]. Accordingly, plants may show corresponding responses to external stresses via TFs regulating target genes.…”

Genome-wide identification and expression analysis of WRKY transcription factors in pearl millet (Pennisetum glaucum) under dehydration and salinity stress

“…Specific transcription factors (TFs, the regulatory proteins) bind to the respective cognate cis-elements present in the promoter region of their target genes and modulate the expression level of genes under particular stress conditions. Such "cis-trans" interactions manifest significantly for controlling the plant survival under adverse environmental conditions [15]. In plants, several TF families have been reported namely ABRE-binding factor (ABF)/ABA-responsive-elementbinding (AREB) [16], ethylene responsive element binding factors (ERF) [16], DREB [17], NAC [18], AP2/ERF [19], WRKY [20], MYB [21], MYC [22] and basic domain leucine zipper (bZIP) [23] etc.…”

Targeted Transcriptional Activation in Plants Using a Potent Dead Cas9–Derived Synthetic Gene Activator

“…These transcriptional activators comprise two functionally independent modules: a programmable DNA‐binding module, which enables sequence‐specific DNA targeting, and a transcriptional activation domain, which induces transcription. Well‐characterized custom DNA‐binding modules include zinc‐finger proteins (ZFPs), TAL effectors, and dCas9 protein (Adli, ; Chen & Qi, ; Shrestha, Khan, & Dey, ). ZFPs and TAL effectors recognize target sequences via protein‐DNA interaction, whereas the targeting specificity of dCas9 protein is conferred by base pairing between a sgRNA and the target DNA.…”