A diversified and segregated mRNA spliced-leader system in the parasitic Perkinsozoa

Abstract

Spliced-leader trans -splicing (SLTS) has been described in distantly related eukaryotes and acts to mark mRNAs with a short 5′ exon, giving different mRNAs identical 5′ sequence-signatures. The function of these systems is obscure. Perkinsozoa encompasses a diversity of parasitic protists that infect bivalves, toxic-tide dinoflagellates, fish and frog tadpoles. Here, we report considerable sequence variation in the SLTS-system across the Perkinsozoa and find that multiple variant SLTS-systems are encoded in parallel in the ecologically important Perkinsozoa parasite Parvilucifera sinerae . These results demonstrate that the transcriptome of P. sinerae is segregated based on the addition of different spliced-leader (SL) exons. This segregation marks different gene categories, suggesting that SL-segregation relates to functional differentiation of the transcriptome. By contrast, both sets of gene categories are present in the single SL-transcript type sampled from Maranthos, implying that the SL-segregation of the Parvilucifera transcriptome is a recent evolutionary innovation . Furthermore, we show that the SLTS-system marks a subsection of the transcriptome with increased mRNA abundance and includes genes that encode the spliceosome system necessary for SLTS-function. Collectively, these data provide a picture of how the SLTS-systems can vary within a major evolutionary group and identify how additional transcriptional-complexity can be achieved through SL-segregation.

Multiple parallel origins of parasitic Marine Alveolates

“…Dinoflagellate nuclei also perform trans-splicing of a highly-conserved spliced leader (SL) to the 5’ end of many or most mRNAs 47 . The same is also true of the perkinsids, however, the SL sequence is more variable 48 . We identified complete SL sequences in a subset of transcripts from eleftherids, MALV-I, and psammosids, and found eleftherids showed variations in sequence from the canonical SL sequence identified in core dinoflagellates and MALVs 15 , 47 (Fig.…”

Multiple parallel origins of parasitic Marine Alveolates

“…Dinoflagellate nuclei also perform trans-splicing of a highly-conserved spliced leader (SL) to the 5 'end of many or most mRNAs 38 . The same is also true of the perkinsids however the SL sequence is more variable 39 . We identified complete SL sequences in a subset of transcripts from eleftherids, MALV I, and psammosids, and found variations in sequence from the canonical SL sequence identified in core dinoflagellates and MALVs 15,38 (Fig.…”

“…We updated the data for the MALVs Amoebophrya ceratii 66 and Hematodinium sp. 14 , for Oxyrrhis marina 60 , for the perkinsids Perkinsus marinus (https://protists.ensembl.org/Perkinsus_marinus_atcc_50983_gca_000006405/Info/Index), Maranthos nigrum and Parvilucifera sinerae 39 , the apicomplexa Ancora sagittate 43 , and for the chromerids Vitrella brassicaformis (https://cryptodb.org/cryptodb/app/record/dataset/NCBITAXON_1169540) and Symbiont X 43 . Transcriptomic datasets were subjected to TransDecoder coding region prediction to extract peptides for downstream analyses.…”

Development of a novel electroporation method for the oyster parasite Perkinsus marinus

“…Therefore, molecular biological analyses between Perkinsozoa and Apicomplexa will be necessary for understanding the parasites' pathogenesis and also the principle of the degeneracy of genome and cellular functions due to parasitism. Because comparative analysis with Apicomplexa provides a generalization of the evolution caused by parasitism, research using Perkinsus is attracting increasing attention from researchers in various fields 12,[15][16][17][18] .Gene manipulation techniques are fundamental to molecular biology and are continuously being improved. However, transgenic methods are still lacking for many non-model organisms, hindering our understanding of their unique cellular systems, although several important progresses have been achieved in the gene transfection project for non-model marine protists 19 .…”

“…Therefore, molecular biological analyses between Perkinsozoa and Apicomplexa will be necessary for understanding the parasites' pathogenesis and also the principle of the degeneracy of genome and cellular functions due to parasitism. Because comparative analysis with Apicomplexa provides a generalization of the evolution caused by parasitism, research using Perkinsus is attracting increasing attention from researchers in various fields 12,[15][16][17][18] .…”