High Throughput Genome-Wide Survey of Small RNAs from the Parasitic Protists Giardia intestinalis and Trichomonas vaginalis

Bulge-helix-bulge (BHB) elements guide the enzymatic splicing machinery that in Archaea excises introns from tRNAs, rRNAs from their primary precursor, and accounts for the assembly of piece-wise encoded tRNAs. This processing pathway renders the intronic sequences as circularized RNA species. Although archaeal transcriptomes harbor a large number of circular small RNAs, it remains unknown whether most or all of them are produced through BHB-dependent splicing. We therefore conduct a genome-wide survey of BHB elements of a phylogenetically diverse set of archaeal species and complement this approach by searching for BHB-like structures in the vicinity of circularized transcripts. We find that besides tRNA introns, the majority of box C/D snoRNAs is associated with BHB elements. Not all circularized sRNAs, however, can be explained by BHB elements, suggesting that there is at least one other mechanism of RNA circularization at work in Archaea. Pattern search methods were unable, however, to identify common sequence and/or secondary structure features that could be characteristic for such a mechanism.

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Global Survey of miRNAs and tRNA-derived Small RNAs From Human Parasitic Protist Trichomonas Vaginalis

10.21203/rs.3.rs-101825/v1 ◽

2020 ◽

Author(s):

Zhensheng Wang ◽

Hongchang Zhou ◽

Chunyan Wei ◽

Zhihua Wang ◽

Xiao Hao ◽

...

Keyword(s):

Small Rnas ◽

Trichomonas Vaginalis ◽

Stem Loop ◽

Sexually Transmitted ◽

Site Analysis ◽

Non Coding Rna ◽

Genome Wide ◽

Parasitic Protist ◽

Non Coding Rnas ◽

Trna Halves

Abstract BackgroundSmall non-coding RNAs play critical regulatory roles in post-transcription. However, their characteristics in Trichomonas vaginalis (T. vaginalis), the causative agent of human sexually transmitted trichomoniasis, still remain to be unveiled. MethodsSmall RNA transcriptomes from Trichomonas trophozoites were deeply sequenced through Illumina NextSeq 500 system and comprehensively analyzed to identify Trichomonas miRNAs and tRNA-derived small RNAs (tsRNAs). The tsRNAs candidates were confirmed by stem-loop RT-PCR and motifs to guide the cleavage of tsRNAs were predicted by performing GLAM2 algorithm. ResultsThe miRNAs were found at extremely low abundance (0.0046%) in T. vaginalis. Three categories of endogenous Trichomonas tsRNAs were identified as 5'tritsRNAs, mid-tritsRNAs and 3'tritsRNAs, with 5'tritsRNAs dominating (67.63%) in tsRNAs. Interestingly, the cleavage site analysis verified both conventional classes of tRFs and tRNA-halves in tritsRNAs, indicating the expression of tRNA-halves in non-stress condition. A total of 25 tritsRNAs were experimentally confirmed, accounting for 78.1% of all tested candidates. Three motifs were predicted to guide the production of tritsRNAs. This proved the expression of tRFs and tRNA-halves in T. vaginalis transcriptome. ConclusionsThis is the first report of genome-wide investigation of small RNAs, particularly tsRNAs and miRNAs, from Trichomonas parasites. Our findings demonstrate the expression profile of tsRNAs in T. vaginalis, while miRNA was hardly discovered. These results might promote the further research to better understand the evolution of small non-coding RNA in T. vaginalis and their functions in pathogenesis of trichomoniasis.

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Global survey of miRNAs and tRNA-derived small RNAs from the human parasitic protist Trichomonas vaginalis

Parasites & Vectors ◽

10.1186/s13071-020-04570-9 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Zhen-Sheng Wang ◽

Hong-Chang Zhou ◽

Chun-Yan Wei ◽

Zhi-Hua Wang ◽

Xiao Hao ◽

...

Keyword(s):

Small Rnas ◽

Trichomonas Vaginalis ◽

Stem Loop ◽

Sexually Transmitted ◽

Site Analysis ◽

Reverse Transcription Pcr ◽

Non Coding Rna ◽

Genome Wide ◽

Parasitic Protist ◽

Trna Halves

Abstract Background Small non-coding RNAs play critical regulatory roles in post-transcription. However, their characteristics in Trichomonas vaginalis, the causative agent of human sexually transmitted trichomoniasis, still remain to be determined. Methods Small RNA transcriptomes from Trichomonas trophozoites were deep sequenced using the Illumina NextSeq 500 system and comprehensively analyzed to identify Trichomonas microRNAs (miRNAs) and transfer RNA (tRNA)-derived small RNAs (tsRNAs). The tsRNA candidates were confirmed by stem-loop quantitative reverse transcription-PCR, and motifs to guide the cleavage of tsRNAs were predicted using the GLAM2 algorithm. Results The miRNAs were found to be present in T. vaginalis but at an extremely low abundance (0.0046%). Three categories of endogenous Trichomonas tsRNAs were identified, namely 5′tritsRNAs, mid-tritsRNAs and 3′tritsRNAs, with the 5′tritsRNAs constituting the dominant category (67.63%) of tsRNAs. Interestingly, the cleavage site analysis verified both conventional classes of tRNA-derived fragments (tRFs) and tRNA-halves in tritsRNAs, indicating the expression of tRNA-halves in the non-stress condition. A total of 25 tritsRNAs were experimentally confirmed, accounting for 78.1% of all tested candidates. Three motifs were predicted to guide the production of tritsRNAs. The results prove the expression of tRFs and tRNA-halves in the T. vaginalis transcriptome. Conclusions This is the first report of genome-wide investigation of small RNAs, particularly tsRNAs and miRNAs, from Trichomonas parasites. Our findings demonstrate the expression profile of tsRNAs in T. vaginalis, while miRNA was barely detected. These results may promote further research aimed at gaining a better understanding of the evolution of small non-coding RNA in T. vaginalis and their functions in the pathogenesis of trichomoniasis.

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