Conservation and diversification of small RNA pathways within flatworms

BMC Evolutionary Biology

Research Article

Jose F. Tort¹  Santiago Fontenla¹  Pablo Smircich²  Gabriel Rinaldi³ 

[1] Departamento de Genética, Facultad de Medicina, Universidad de la República (UDELAR), Gral. Flores 2125, CP11800, Montevideo, MVD, Uruguay;Departamento de Genética, Facultad de Medicina, Universidad de la República (UDELAR), Gral. Flores 2125, CP11800, Montevideo, MVD, Uruguay;Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Universidad de la República (UdelaR), Montevideo, Uruguay;Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, Cambridge, UK;

关键词: Flatworms;    Small RNA pathways;    miRNA;    RNAi;    Dicer;    Argonaute;   

DOI  :  10.1186/s12862-017-1061-5

 received in 2017-06-07, accepted in 2017-09-05,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundSmall non-coding RNAs, including miRNAs, and gene silencing mediated by RNA interference have been described in free-living and parasitic lineages of flatworms, but only few key factors of the small RNA pathways have been exhaustively investigated in a limited number of species. The availability of flatworm draft genomes and predicted proteomes allowed us to perform an extended survey of the genes involved in small non-coding RNA pathways in this phylum.ResultsOverall, findings show that the small non-coding RNA pathways are conserved in all the analyzed flatworm linages; however notable peculiarities were identified. While Piwi genes are amplified in free-living worms they are completely absent in all parasitic species. Remarkably all flatworms share a specific Argonaute family (FL-Ago) that has been independently amplified in different lineages. Other key factors such as Dicer are also duplicated, with Dicer-2 showing structural differences between trematodes, cestodes and free-living flatworms. Similarly, a very divergent GW182 Argonaute interacting protein was identified in all flatworm linages. Contrasting to this, genes involved in the amplification of the RNAi interfering signal were detected only in the ancestral free living species Macrostomum lignano. We here described all the putative small RNA pathways present in both free living and parasitic flatworm lineages.ConclusionThese findings highlight innovations specifically evolved in platyhelminths presumably associated with novel mechanisms of gene expression regulation mediated by small RNA pathways that differ to what has been classically described in model organisms. Understanding these phylum-specific innovations and the differences between free living and parasitic species might provide clues to adaptations to parasitism, and would be relevant for gene-silencing technology development for parasitic flatworms that infect hundreds of million people worldwide.

【 授权许可】

CC BY   
© The Author(s). 2017