Insights into the Functions of LncRNAs in Drosophila

Abstract

Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs longer than 200 nucleotides (nt). LncRNAs have high spatiotemporal specificity, and secondary structures have been preserved throughout evolution. They have been implicated in a range of biological processes and diseases and are emerging as key regulators of gene expression at the epigenetic, transcriptional, and post-transcriptional levels. Comparative analyses of lncRNA functions among multiple organisms have suggested that some of their mechanisms seem to be conserved. Transcriptome studies have found that some Drosophila lncRNAs have highly specific expression patterns in embryos, nerves, and gonads. In vivo studies of lncRNAs have revealed that dysregulated expression of lncRNAs in Drosophila may result in impaired embryo development, impaired neurological and gonadal functions, and poor stress resistance. In this review, we summarize the epigenetic, transcriptional, and post-transcriptional mechanisms of lncRNAs and mainly focus on recent insights into the transcriptome studies and biological functions of lncRNAs in Drosophila.

Keywords: Drosophila; biological function; long non-coding RNAs; mechanism; transcriptome.

Figure 1

The biological function of long non-coding RNAs (lncRNAs) in Drosophila. LncRNAs regulate development (embryo, organ, and neuromuscular junction), behaviour (sleep, locomotion, courtship, and mating), sex determination, and dosage compensation in Drosophila. LncRNAs can also protect fruit flies from some stressors, such as heat and infection by bacteria and wasps.

Figure 2

The epigenetic, transcriptional, and post-transcriptional mechanisms of lncRNAs. (A) Role of lncRNAs in the epigenetic regulation. (a) DNA methylation [25,26]. (b) Histone modification [27,28]. (c) Chromatin remodelling [29,30]. (B) Role of lncRNAs in transcriptional regulation. (a,b) LncRNAs regulate the binding of transcription factors to target genes [31,32]. (C) Role of lncRNAs in post-transcriptional regulation. (a) LncRNAs can serve as precursors of miRNAs, small interfering RNAs (siRNAs), or piwi-interacting RNAs (piRNAs) [33,34,35]. (b) LncRNAs can regulate alternative splicing [36]. (c) LncRNAs, such as metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), can act as molecular scaffolds, allowing the assembly of protein complexes [37]. (d) LncRNAs control mRNA levels by functioning as competing endogenous RNAs (ceRNAs) [38]. (e) Some lncRNAs may encode micropeptides [39,40]. (f) LncRNAs may block the activity of protein receptors [41]. (g,h) LncRNAs can directly regulate the stability and translation of mRNAs [42,43,44,45].