Fig. 1
From: Drosophila primary microRNA-8 encodes a microRNA-encoded peptide acting in parallel of miR-8
Translatability of pri-miR-8. a Model of miPEP regulation in plants. b Box plot representation of the number of ORFs in different classes of RNAs. 3′UTR, 5′UTR and CDS represent coding RNAs, whereas lncRNAs and pri-miRs represent non-coding RNAs. An ORF was defined as starting with an ATG and coding for a minimum of 10 amino acids. Pri-miRs reveal comparable numbers of ORFs/kb as lncRNAs. c GWIPS-vis [42] genome viewer of the Drosophila miR-8 locus. Top: genomic positions and ORFs in the three reading frames. Green bars define ATGs and red bars stop codons. Below, RNA-seq profile is shown in green and ribosome profiling is shown in red. The blue horizontal lines represent the two CR43650 non-coding RNA transcripts and potential miR-8 pri-miRs. In black is schematized the transcript we identified as detectable pri-miR-8. Bottom: miPEP-8 amino acid sequence is shown. d Western blot experiments using the anti-miPEP-8 antibody. Left panel: in vitro synthetized miPEP-8 corresponding to the constructs indicated on top. The asterisk indicates the upstream initiated peptide. The arrow indicates the miPEP-8 initiated at ATG1. Middle panel: detection of miPEP-8 in S2 cells over-expressing miPEP-8 placed in different translational contexts; Kozak (optimal); K mt (ATG mutated into TGA); mt (ATG mutated into AGT). Note that the pri-miR is translated and endogenous miPEP-8 expression is undetectable in S2 cells. Right panel: anti miPEP-8 western blot of adult Drosophila extracts and in the miR-8 deleted line Δ2/Δ2 [26] in which no miPEP-8 is detected. We noticed the presence of non-specific bands as well as additional specific bands representing possibly miPEP-8 multimeric forms or PTM modifications. Ctrl corresponds to cell extracts transfected with an empty vector