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:Genomic assembly of cestode Mesocestoides corti, as part of the 50 Helminth Genomes Initiative sequencing of the parasitic worms that have the greatest impact on human, agricultural and veterinary disease and cause significant global health issues particularly in the developing world, or those used as model organisms.
Project description:The microRNA miR-96 is important for hearing; mutations in the seed region result in dominant progressive hearing loss in mice and humans. Mir96 is expressed in the sensory hair cells of the organ of Corti along with Mir182 and Mir183. miR-96 is a master regulator of hair cell development, controlling many genes in the organ of Corti, but the role of miR-182 and miR-183 in the hair cells is unknown. We carried out RNA-seq on mice carrying a knockout allele of Mir182, and mice carrying a double knockout allele of Mir183 and Mir96 (Mir183/96). RNA was extracted from the organ of Corti from P4 homozygotes and sex-matched wildtype littermates. Strand-specific libraries were prepared using the NuGEN Ovation Mouse RNA-Seq System 1-16 kit and sequenced on an Illumina HiSeq 2500 machine as paired-end 125bp reads.
Project description:Mutations affecting the microRNA miR-96 have been found to cause progressive hearing loss in humans and in mice. These initial mutations were all semidominant, so phenotypes were present in heterozygous carriers. The similarity of the phenotype between the different mutations suggested that it was the loss of normal function of Mir96 that underlay the hearing impairment. However, more recent studies of null alleles of Mir96 and the nearby Mir183, and of Mir96, Mir182 and Mir183 all together, showed that heterozygous carriers of the null alleles have no hearing phenotype, suggesting that the gain of novel targets due to the changed seed sequence resulting from point mutations is important in the Mir96 mutant phenotype, not just the loss of normal targeting. Previous transcriptome analyses of the Mir96 mutant organ of Corti showed that miR-96 controls a broad regulatory network, suggesting that a better understanding of the core genes – particularly the direct targets of miR-96 – may suggest candidate therapeutic targets. We carried out RNA-seq on mice carrying the two seed region point mutations reported in human families. RNA was extracted from the organ of Corti from four day-old homozygotes and sex-matched wildtype littermates. Strand-specific libraries were prepared following the “TruSeq Stranded mRNA Sample Preparation Guide” with the corresponding kit [Illumina Inc. Cat.# RS-122-2101 or RS-122-2102], and sequenced on an Illumina HiSeq 4000 machine as paired-end 101bp reads.
Project description:Mutations affecting the microRNA miR-96 have been found to cause progressive hearing loss in humans and in mice. These initial mutations were all semidominant, so phenotypes were present in heterozygous carriers. The similarity of the phenotype between the different mutations suggested that it was the loss of normal function of Mir96 that underlay the hearing impairment. However, more recent studies of null alleles of Mir96 and the nearby Mir183, and of Mir96, Mir182 and Mir183 all together, showed that heterozygous carriers of the null alleles have no hearing phenotype, suggesting that the gain of novel targets due to the changed seed sequence resulting from point mutations is important in the Mir96 mutant phenotype, not just the loss of normal targeting. Previous transcriptome analyses of the Mir96 mutant organ of Corti showed that miR-96 controls a broad regulatory network, suggesting that a better understanding of the core genes – particularly the direct targets of miR-96 – may suggest candidate therapeutic targets. We carried out RNA-seq on mice carrying the two seed region point mutations reported in human families. RNA was extracted from the organ of Corti from four day-old homozygotes and sex-matched wildtype littermates. Strand-specific libraries were prepared following the “TruSeq Stranded mRNA Sample Preparation Guide” with the corresponding kit [Illumina Inc. Cat.# RS-122-2101 or RS-122-2102], and sequenced on an Illumina HiSeq 4000 machine as paired-end 101bp reads.
Project description:Mesocestoides corti is a widely used model for the study of cestode biology, and its transition from the larval tetrathyridium (TT) stage to the strobilated, adult worm (ST) stage can be induced and followed in vitro. Here, a proteomic approach was used to describe and compare M. corti TT and ST protein repertories. Overall, 571 proteins were identified, 238 proteins in TT samples and 333 proteins in ST samples. Among the identified proteins, 207 proteins were shared by TTs and STs, while 157 were stage-specific, being 31 exclusive from TTs, and 126 from STs. Functional annotation revealed fundamental metabolic differences between the TT and the ST stages. TTs perform functions related mainly to basic metabolism, responsible for growth and vegetative development by asexual reproduction. STs, in contrast, perform a wider range of functions, including macromolecule biosynthetic processes, gene expression and control pathways, which may be associated to its proglottization/segmentation, sexual differentiation and more complex physiology. Furthermore, the generated results provided an extensive list of cestode proteins of interest for functional studies in M. corti. Many of these proteins are novel candidate diagnostic antigens, and/or potential targets for the development of new and more effective antihelminthic drugs.Biological significanceCestodiases are parasitic diseases with serious impact on human and animal health. Efforts to develop more effective strategies for diagnosis, treatment or control of cestodiases are impaired by the still limited knowledge on many aspects of cestode biology, including the complex developmental processes that occur in the life cycles of these parasites. Mesocestoides corti is a good experimental model to study the transition from the larval to the adult stage, called strobilation, which occur in typical cestode life-cycles. The performed proteomics approach provided large-scale identification and quantification of M. corti proteins. Many stage-specific or differentially expressed proteins were detected in the larval tetrathyridium (TT) stage and in the strobilated, adult worm (ST) stage. Functional comparative analyses of the described protein repertoires shed light on function and processes associated to specific features of both stages, such as less differentiation and asexual reproduction in TTs, and proglottization/segmentation and sexual differentiation in ST. Moreover, many of the identified stage-specific proteins are useful as cestode developmental markers, and are potential targets for development of novel diagnostic methods and therapeutic drugs for cestodiases.