Project description:MicroRNAs (miRNAs), a class of small non-coding RNAs, are key regulators of gene expression at post-transcriptional level and play essential roles in fundamental biological processes such as metabolism and development. The particular developmental characteristics of cestode parasites highlight the importance of studying miRNA gene regulation in these organisms. Here, we performed a comprehensive analysis of miRNAs in two developmental stages of the model cestode Mesocestoides corti. Using a high-throughput sequencing approach, we found transcriptional evidence of 42 miRNA loci in tetrathyridia larvae and strobilated worms. Tetrathyridium and strobilated worm-specific miRNAs were found, as well as differentialy expressed miRNAs between these developmental stages, suggesting miRNA regulation of stage-specific features. Moreover, it was shown that uridylation is a differential mechanism of post-transcriptional modification of M. corti miRNAs. The whole set of M. corti miRNAs represent 33 unique miRNA families, and confirm the remarkable loss of conserved miRNA families within platyhelminth parasites, reflecting their relatively low morphological complexity and high adaptation to parasitism. Overall, the presented results provide a valuable platform to studies aiming to identify and characterize novel miRNA-based molecular mechanisms of post-transcriptional gene regulation in cestodes, necessary for the elucidation of developmental aspects of the complex biology of these parasites.
Project description:The cestodes Echinococcus granulosus and Echinococcus multilocularis, as the pathogens of cystic echinococcosis and alveolar echinococcosis respectively, can cause significant health problems to the host and considerable socio-economic losses as a consequence. Based on the genomic data regarding these two species available in public database recently, we carried out high-throughput mRNA and small RNA transcriptomic sequencing of them and generate enormous transcriptomic datasets. A total of 34,717,856 reads (79.79%) mapped to E. granulosus genome, and 38,882,179 reads (87.61%) mapped to E. multiloculari genome. A total of 24,550 (7,925 known and 16,625 novel transcripts) and 23,771 transcripts (8,432 known and 15,339 novel transcripts) were assembled for E. granulosus and E. multilocularis respectively, and the assembly yielded 11,330 genes (6,815 known and 4,515 novel genes) for E. granulosus and 10,101 genes (7,051 known and 3,050 novel genes) for E. multilocularis, compared with the reference genome data. Bioinformatic analysis identified 6,826 AS events from 3,774 E. granulosus genes (33.31%) and 6,644 AS events in 3,611 E. multilocularis genes (35.75%). A total of 76,674 distinct microRNAs of E. granulosus and 115,742 of E. multilocularis were also obtained from small RNA transcriptome sequencing reads. Of these, there were 20 microRNAs of E. granulosus and 22 microRNAs of E. multilocularis that belonged to 19 and 21 microRNA families common to other metazoan lineages separately. 76 and 90 novel microRNAs so far unique to E. granulosus and E. multilocularis were also identified respectively. This study represents an extensive mRNA and small RNA transcriptome dataset obtained from the deep sequencing of these two cestode species. The findings will facilitate a more fundamental understanding of cestode biology, evolution, the host-parasite interplay, and provide new insights into the pathophysiology of echinococcosis, contributing to the development of improved interventions for disease control.