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: As part of this analysis, we identified spliced leaders in T. muris, leading to the discovery of 13 Tmu-SLs (Figure 2; Table S2). Previous studies have shown that the primary sequences of spliced leaders in T. spiralis are much more variable than those found in the Chromadorea (Pettitt et al. 2008), and many lack the conserved motifs that characterize spliced leaders from these latter nematodes. In contrast, those of P. punctatus do not show the same diversity and display a greater degree of sequence similarity to the Chromadorid spliced leaders (Harrison et al. 2010). Analysis of the 13 distinct T. muris spliced leaders, designated Tmu-SL1–13, support this view, since the T. muris spliced leaders possess the same 5′ GGUWW and central CCC motifs that are highly conserved in the P. punctatus spliced leaders and Chromadorid SL1 and SL2 families, but missing in most of the T. spiralis spliced leaders. The presence of canonical nematode spliced leaders in T. muris and P. punctatus, despite the fact that the former nematode is more closely related to T. spiralis, supports the inference that the T. spiralis spliced leaders are derived features.
Affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom firstname.lastname@example.org.