Skip to main content
Fig. 3 | Mobile DNA

Fig. 3

From: Transposable element-derived sequences in vertebrate development

Fig. 3

Functions of TE-derived non-coding RNAs. a Mechanisms of action of TE-derived small non-coding RNAs (sncRNAs) through sequence complementarity. TE-derived sncRNAs are formed by fragmentation of TE-derived transcripts [122, 294], siRNAs being generated through the cleavage of the successive precursors pri-miRNAs and pre-miRNAs [122]. TE-derived sncRNAs, associated to proteins (RNA-induced silencing complex for miRNAs [122], PIWI proteins for piRNAs [150]) form double-stranded RNAs with complementarity to some RNAs of the host transcriptome, this leading to the cleavage of RNAs (1) and to the inhibition of translation (2). sncRNAs also mediates the heterochromatinization of TEs to silence them after the recruitment of DNA and histone methyltransferases (3). This heterochromatinization can spread to neighboring regions, altering their expression. b Evolution and function of the xist gene. Top: the human xist lncRNA gene has been formed after ancient insertions of several TEs (red boxes) into the ancestral protein-coding lnx3 gene, which is still present in chicken. lnx3 blue boxes represent the exons homologous to xist exons and dark grey boxes other exons. Xist shaded boxes represent human pseudo-exons (intronic regions in human but exonic in other species). Red arrows indicate TE and xist exon homology. Bottom: Xist lncRNAs coat the X chromosome, leading to X chromosome inactivation, which is facilitated by LINE-1 elements present on the chromosome [190, 191]. Silhouette images from http://phylopic.org

Back to article page