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Identification and characterization of microRNAs from Cochliomyia hominivorax and Cochliomyia macellaria (Diptera: Calliphoridae)

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Daniel Fernando Paulo
Total Authors: 1
Document type: Master's Dissertation
Press: Campinas, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
Defense date:
Examining board members:
Ana Maria Lima de Azeredo Espin; Zilá Luz Paulino Simões; Guilherme Targino Valente
Advisor: Ana Carolina Martins Junqueira; Ana Maria Lima de Azeredo Espin

MicroRNAs (miRNAs) are small non-coding RNAs that act as post-transcriptional modulators of gene expression in all eukaryotes investigated so far. The imperfect complementarity between miRNA and the target site of messenger RNA (mRNA) inhibits their translation in animals, being key genes for the control of expression in cells. The identification of miRNAs can provide a better understanding of biological processes and evolution of traits in different species. The family Calliphoridae is a group of myiasis-causing flies with different feeding habits, which includes the species Cochliomyia hominivorax (screwworm fly) and Cochliomyia macellaria (secondary screwworm). The screwworm fly is one of the major pests in the Neotropical region. Their larvae infest and feed on live tissues of warm-blooded vertebrates, resulting in severe losses for livestock industry. Differently, the close-related secondary screwworm shows a saprophagous habit, feeding and breeding on carcasses and dead tissues, being crucial for forensic entomology and public health. Because of their close evolutionary relationship and contrasting feeding habits, they represent worthy models to study the molecular basis of parasitism and feeding specialization in the family Calliphoridae. To characterize the miRNAs from both species, the small-RNA transcriptomes of adults (male and female) and larvae (third instar) were sequenced using Illumina-MiSeq next generation sequencing platform. The 6.2 million reads generated were mapped against the Drosophila melanogaster genome and screened in miRBase. We identified 84 evolutionary conserved miRNAs which 80 was founded in C. hominivorax and 78 in C. macellaria. We also investigated the presence of hairpin precursors (pre-miRNAs) in the available genomic and transcriptomic data of these species, and predicted 10 conserved pre-miRNAs and others 5 that show no similarity with previously described animal miRNAs. The evolutionary characterization of identified miRNAs showed that their sequences were highly conserved since the Nephrozoa ancestor (641 MYA) in the basis of Bilaterian clade, until Brachycera ancestor (195 MYA), with nucleotide substitutions biased to 3¿-end portion of the miRNAs with rare substitutions in the seed region. The preliminary expression profile revealed 79 differentially expressed miRNAs between species, gender and life stages, given by hierarchical clustering and statistically significant change fold analysis. The results presented here will provide new information about the genetic background of parasitic habits in C. hominivorax and C. macellaria, with prospects to functional and evolutionary studies in Calliphoridae and pest control (AU)

FAPESP's process: 12/06272-0 - Identification and characterization of microRNAs in Cochliomyia hominivorax and Cochliomyia macellaria (Diptera: Calliphoridae)
Grantee:Daniel Fernando Paulo
Support Opportunities: Scholarships in Brazil - Master