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Operons are a conserved feature of nematode genomes.

Pettitt J, Philippe L, Sarkar D, Johnston C, Gothe HJ, Massie D, Connolly B, Müller B - Genetics (2014)

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.

View Article: PubMed Central - PubMed

Affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom j.pettitt@abdn.ac.uk.

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Evolutionary relationship between snRNPs associated with SL trans-splicing. Unrooted PhyML tree showing the relationship between sna-1 and sut-1 homologs identified in selected nematodes. Genes were named on the basis of their C. elegans homologs. The following species-specific prefixes were used: Aca, Angiostrongylus cantonensis; Asu, Ascaris suum; Bma, Brugia malayi; Cel, C. elegans; Cbr, C. briggsae; Cre, C. remanei; Hco, Haemochus contortus; Llo, Loa loa; Nam, Necator americanus; Rcu, Romanomermis culicivorax; and Wba, Wucheria bancrofti. The numbers at each node are approximate likelihood ratio test statistics.
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fig5: Evolutionary relationship between snRNPs associated with SL trans-splicing. Unrooted PhyML tree showing the relationship between sna-1 and sut-1 homologs identified in selected nematodes. Genes were named on the basis of their C. elegans homologs. The following species-specific prefixes were used: Aca, Angiostrongylus cantonensis; Asu, Ascaris suum; Bma, Brugia malayi; Cel, C. elegans; Cbr, C. briggsae; Cre, C. remanei; Hco, Haemochus contortus; Llo, Loa loa; Nam, Necator americanus; Rcu, Romanomermis culicivorax; and Wba, Wucheria bancrofti. The numbers at each node are approximate likelihood ratio test statistics.

Mentions: We were able to identify credible homologs of sna-2 in the genomes of all nematodes in which searches were carried out, including T. spiralis and R. culicovorax, indicating that this gene encodes a nematode-wide SL trans-splicing component (Figure S2). Searches of the same datasets identified clear sna-1 and sut-1 orthologs in the chromadorean nematodes (Figure 5), extending the previously reported phylogenetic distribution of sut-1 (MacMorris et al. 2007). In contrast, the only enoplean genome in which we were able to identify a sut-1 homolog was R. culicivorax (Figure 5). We could not detect sna-1 homologs in any of the enoplean genomes that we assayed. These data suggest that the gene duplication event that gave rise to sna-1 and sut-1 occurred after the separation of the two major nematode taxa; however, we cannot rule out that the possibility that our failure to detect sna-1 homologs is due to the incomplete state of the enoplean genome drafts.


Operons are a conserved feature of nematode genomes.

Pettitt J, Philippe L, Sarkar D, Johnston C, Gothe HJ, Massie D, Connolly B, Müller B - Genetics (2014)

Evolutionary relationship between snRNPs associated with SL trans-splicing. Unrooted PhyML tree showing the relationship between sna-1 and sut-1 homologs identified in selected nematodes. Genes were named on the basis of their C. elegans homologs. The following species-specific prefixes were used: Aca, Angiostrongylus cantonensis; Asu, Ascaris suum; Bma, Brugia malayi; Cel, C. elegans; Cbr, C. briggsae; Cre, C. remanei; Hco, Haemochus contortus; Llo, Loa loa; Nam, Necator americanus; Rcu, Romanomermis culicivorax; and Wba, Wucheria bancrofti. The numbers at each node are approximate likelihood ratio test statistics.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4125394&req=5

fig5: Evolutionary relationship between snRNPs associated with SL trans-splicing. Unrooted PhyML tree showing the relationship between sna-1 and sut-1 homologs identified in selected nematodes. Genes were named on the basis of their C. elegans homologs. The following species-specific prefixes were used: Aca, Angiostrongylus cantonensis; Asu, Ascaris suum; Bma, Brugia malayi; Cel, C. elegans; Cbr, C. briggsae; Cre, C. remanei; Hco, Haemochus contortus; Llo, Loa loa; Nam, Necator americanus; Rcu, Romanomermis culicivorax; and Wba, Wucheria bancrofti. The numbers at each node are approximate likelihood ratio test statistics.
Mentions: We were able to identify credible homologs of sna-2 in the genomes of all nematodes in which searches were carried out, including T. spiralis and R. culicovorax, indicating that this gene encodes a nematode-wide SL trans-splicing component (Figure S2). Searches of the same datasets identified clear sna-1 and sut-1 orthologs in the chromadorean nematodes (Figure 5), extending the previously reported phylogenetic distribution of sut-1 (MacMorris et al. 2007). In contrast, the only enoplean genome in which we were able to identify a sut-1 homolog was R. culicivorax (Figure 5). We could not detect sna-1 homologs in any of the enoplean genomes that we assayed. These data suggest that the gene duplication event that gave rise to sna-1 and sut-1 occurred after the separation of the two major nematode taxa; however, we cannot rule out that the possibility that our failure to detect sna-1 homologs is due to the incomplete state of the enoplean genome drafts.

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.

View Article: PubMed Central - PubMed

Affiliation: School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom j.pettitt@abdn.ac.uk.

Show MeSH
Related in: MedlinePlus