Operons are a conserved feature of nematode genomes.
Bottom Line: The organization of genes into operons, clusters of genes that are co-transcribed to produce polycistronic pre-mRNAs, is a trait found in a wide range of eukaryotic groups, including multiple animal phyla.We have nevertheless identified putative operons conserved between Enoplea and Chromadorea.Our data suggest that operons and "spliced leader" (SL) trans-splicing predate the radiation of the nematode phylum, an inference which is supported by the phylogenetic profile of proteins known to be involved in nematode SL trans-splicing.
Affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom email@example.com.Show MeSH
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Mentions: Analysis of the intercistronic region between Tsp-cpt-2 and nuaf-3 downstream of the polyadenylation signal of Tsp-cpt-2 revealed a clear Ur element and there are several U-rich regions, characteristics of the ICRs in C. elegans operons (Graber et al. 2007). To investigate the possibility that this region is able to function in polycistronic RNA processing, we determined whether the ICR from it could be recognized and processed if heterologously expressed in C. elegans. We generated an artificial operon consisting of sur-5::gfp (Gu et al. 1998) and mCherry genes flanking the ICR from Tsp-cpt-2∼nuaf-3. Transgenic animals carrying this construct expressed nuclear GFP and cytoplasmic mCherry, consistent with the processing of the two coding regions under the direction of the Tsp-cpt-2∼nuaf-3 ICR. We confirmed that this involved trans-splicing to SL2, as expected for polycistronic RNA processing in C. elegans, by showing that we could detect SL2 trans-splicing to the mCherry mRNA in RNA derived from transgenic animals (Figure 4). Thus, the predicted ICR between Tsp-cpt-2 and nuaf-3 is recognized and used as a substrate for polycistronic RNA processing in C. elegans.
Affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom firstname.lastname@example.org.