“What You Need, Baby, I Got It”: Transposable Elements as Suppliers of Cis-Operating Sequences in Drosophila

Abstract

Transposable elements (TEs) are constitutive components of both eukaryotic and prokaryotic genomes. The role of TEs in the evolution of genes and genomes has been widely assessed over the past years in a variety of model and non-model organisms. Drosophila is undoubtedly among the most powerful model organisms used for the purpose of studying the role of transposons and their effects on the stability and evolution of genes and genomes. Besides their most intuitive role as insertional mutagens, TEs can modify the transcriptional pattern of host genes by juxtaposing new cis-regulatory sequences. A key element of TE biology is that they carry transcriptional control elements that fine-tune the transcription of their own genes, but that can also perturb the transcriptional activity of neighboring host genes. From this perspective, the transposition-mediated modulation of gene expression is an important issue for the short-term adaptation of physiological functions to the environmental changes, and for long-term evolutionary changes. Here, we review the current literature concerning the regulatory and structural elements operating in cis provided by TEs in Drosophila. Furthermore, we highlight that, besides their influence on both TEs and host genes expression, they can affect the chromatin structure and epigenetic status as well as both the chromosome's structure and stability. It emerges that Drosophila is a good model organism to study the effect of TE-linked regulatory sequences, and it could help future studies on TE-host interactions in any complex eukaryotic genome.

Non-Random Genome Editing and Natural Cellular Engineering in Cognition-Based Evolution

“…Such retroelements are acknowledged participants in adaptive evolution [ 96 ] and are a source of evolutionary novelty [ 99 , 169 ]. Each are residues of previous infectious interchanges [ 92 ] that can affect both somatic and germ cells, contribute to cis-regulatory DNA elements, and modify transcriptional networks [ 108 , 109 , 173 ]. Notably, flexible adaptation is ongoing among the various functional and non-coding RNAs that enable RNA-mediated cell processes that contribute to the adaptive ability of cells to meet environmental impacts [ 174 ].…”

“…Waves of expansion of TE families have contributed to the repertoire of transcription factors and cis-regulatory sequences in mammalian genomes [ 108 ]. Experiments in the model organism, Drosophila , confirm that TEs can modify the transcriptional pattern of host genes to contribute to short-term adaptations of physiological capacity to environmental stresses [ 109 ]. It is now believed that centromeric chromatin in most eukaryotes is composed of highly repetitive centromeric retrotransposons that participate in cell division [ 110 ].…”

KRAB-ZFP Transcriptional Regulators Acting as Oncogenes and Tumor Suppressors: An Overview

“…Moreover, TEs may serve as a rich source of various cis-regulatory sequences, including enhancers, promoters, suppressors, insulators, and TF-binding sites, thus providing transcriptional and epigenetic control over neighboring genes [ 50 , 51 ]. For instance, the de-repression of certain TE-derived enhancers is crucial for the activation of the embryonic genome in the preimplantation embryos.…”

Oxidative and radiation stress induces transposable element transcription in Drosophila melanogaster

“…In addition, several recent studies have characterized the TE promoter regions by identifying transcription factor binding sites (TFBSs), particularly those related to a regulatory network in the presence of stressors, and the potential role of TEs in the stress response. These studies showed that several TEs have stress‐related TFBSs (Moschetti et al., 2020; Rech et al., 2019; Villanueva‐Cañas et al., 2019) or that the stressor may affect the epigenetic mark of TEs or the proteins associated with TE expression (Cappucci et al., 2019; Guio et al., 2018). In addition, several studies have addressed the effect of different stressors on the transcriptome response in D. melanogaster , aiming to reveal the different stress regulation networks underlying the organism's responses.…”