A <i>Gypsy</i> element contributes to the nuclear retention and transcriptional regulation of the resident lncRNA in locusts

The majority of long noncoding RNAs (lncRNAs) contain transposable elements (TEs). <i>PAHAL</i>, a nuclear-retained lncRNA that is inserted by a <i>Gypsy</i> retrotransposon, has been shown to be a vital regulator of phenylalanine hydroxylase (<i>PAH</i>) gene expression that controls dopamine biosynthesis and behavioural aggregation in the migratory locust. However, the role of the <i>Gypsy</i> retrotransposon in the transcriptional regulation of <i>PAHAL</i> remains unknown. Here, we identified a <i>Gypsy</i> retrotransposon (named <i>Gypsy</i> element) as an inverted long terminal repeat located in the 3′ end of <i>PAHAL</i>, representing a feature shared by many other lncRNAs in the locust genome. The embedded <i>Gypsy</i> element contains a RNA nuclear localization signal motif, which promotes the stable accumulation of <i>PAHAL</i> in the nucleus. The <i>Gypsy</i> element also provides high-affinity SRSF2 binding sites for <i>PAHAL</i> that induce the recruitment of SRSF2, resulting in the <i>PAHAL</i>-mediated transcriptional activation of <i>PAH</i>. Thus, our data demonstrate that TEs provide discrete functional domains for lncRNA organization and highlight the contribution of TEs to the regulatory significance of lncRNAs.