RT Journal Article SR Electronic T1 Human USP18 is regulated by miRNAs via the 3’UTR, a sequence duplicated in lincRNA genes residing in chr22q11.21 JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.10.07.328385 DO 10.1101/2020.10.07.328385 A1 Erminia Rubino A1 Melania Cruciani A1 Nicolas Tchitchek A1 Anna Le Tortorec A1 Antoine D. Rolland A1 Önay Veli A1 Leslie Vallet A1 Giulia Gaggi A1 Frédérique Michel A1 Nathalie Dejucq-Rainsford A1 Sandra Pellegrini YR 2020 UL http://biorxiv.org/content/early/2020/10/08/2020.10.07.328385.abstract AB Ubiquitin-specific peptidase 18 (USP18) acts as gatekeeper of type I interferon (IFN) responses by binding to the IFN receptor subunit IFNAR2 and preventing activation of the downstream JAK/STAT pathway. In any given cell type, the level of USP18 is a key determinant of the output of interferon-stimulated transcripts. How the baseline level of USP18 is finely tuned in different cell types remains ill defined. Here we explored post-transcriptional regulation of USP18 by microRNAs (miRNAs) and identified four miRNAs (miR-24-3p, miR-191-5p, miR-423-5p and miR-532-3p) that efficiently target USP18 through binding to the 3’UTR. Among these, three miRNAs are particularly enriched in circulating monocytes which exhibit low baseline USP18. Intriguingly, the USP18 3’UTR sequence is duplicated in human and chimpanzee genomes. In human, we found several copies of the 3’UTR that are embedded in long intergenic non-coding (linc) RNA genes residing in chr22q11.21 and exhibiting a tissue-specific expression pattern. Interestingly, one of these lincRNAs (here named linc-UR-B1) is uniquely and highly expressed in testis. RNA-seq data analyses from testicular cell subsets revealed a positive correlation between linc-UR-B1 and USP18 expression in spermatocytes and spermatids. Overall, our findings uncover a set of miRNAs and lincRNAs, which may be part of a network evolved to fine-tune baseline USP18, particularly in cell types where IFN responsiveness needs to be tightly controlled.SIGNIFICANT STATEMENT USP18 is a non-redundant negative feedback regulator of type I IFN signaling and a key determinant of cell responsiveness to IFN. How baseline USP18 is set in different human cell types is ill defined. We identified three microRNAs that restrain USP18 level notably in primary monocytes through binding the 3’UTR. We found several copies of the USP18 3’UTR embedded in long intergenic non-coding (linc) RNAs which reside in a complex region of human chromosome 22. These lincRNAs are expressed in a tissue-specific manner. We describe one lincRNA expressed only in testis, and most notably in germ cells. Correlative analyses suggest that microRNAs and lincRNAs may form a network controlling baseline USP18 and IFN responsiveness.Competing Interest StatementThe authors have declared no competing interest.