The developmentally dynamic microRNA transcriptome of Glossina pallidipes tsetse flies, vectors of animal trypanosomiasis

Abstract

MicroRNAs (miRNAs) are single stranded gene regulators of 18-25 bp in length. They play a crucial role in regulating several biological processes in insects. However, the functions of miRNA in Glossina pallidipes, one of the biological vectors of African animal trypanosomosis (AAT) in sub-Saharan Africa, remain poorly characterised. We used a combination of both molecular biology and bioinformatics techniques to identify miRNA genes at different developmental stages (larvae, pupae, teneral and reproductive unmated adults, gravid females) and sexes of G. pallidipes. We identified 157 mature miRNA genes, including 12 novel miRNAs unique to G. pallidipes. Moreover, we identified 93 miRNA genes that were differentially expressed by sex and/or in specific developmental stages. By combining both miRanda and RNAhybrid algorithms, we identified 5550 of their target genes. Further analyses with the GO term and KEGG pathways for these predicted target genes suggested that the miRNAs may be involved in key developmental biological processes. Our results provide the first repository of G. pallidipes miRNAs across developmental stages, some of which appear to play crucial roles in tsetse fly development. Hence, our findings provide a better understanding of tsetse biology and a baseline for exploring microRNA genes in tsetse flies. Availability Raw sequence data is available from NCBI Sequence Read Archives (SRA) under Bioproject accession number PRJNA590626. Supplementary information Supplementary data are available at Bioinformatics Advances online. (Supplementary Figures S1-S4; Supplementary Tables S1 and S2)

microRNA Expression Dynamics in Culicoides sonorensis Biting Midges Following Blood-Feeding

“…Indeed, our data also support the idea that these miRNA clusters are evolutionarily distinct from Culicomorpha, which contain mosquitoes (Culicidae) and midges (Ceratopogonidae). While the miR-309 cluster is observed in other hematophagous dipterans, stable flies [67] and tsetse flies [55,56], these organisms lack miRNAs miR-2944a and miR-2944b. Interestingly, miR-1174 cluster is conserved across mosquito species [68] but not found in current miRNA libraries for other hematophagous Diptera such as Lutzomyia [58], Glossina [55,56], Cochliomyia [57], and Stomoxys [67].…”

“…While the miR-309 cluster is observed in other hematophagous dipterans, stable flies [67] and tsetse flies [55,56], these organisms lack miRNAs miR-2944a and miR-2944b. Interestingly, miR-1174 cluster is conserved across mosquito species [68] but not found in current miRNA libraries for other hematophagous Diptera such as Lutzomyia [58], Glossina [55,56], Cochliomyia [57], and Stomoxys [67]. Together, these data suggest that the expansion of the miR-309 cluster and the origin of the miR-1174 cluster are evolutionarily distinct to Culicomorpha, as mosquitoes (Culicidae) and midges (Ceratopogonidae) share an evolutionary origin for hematophagy that is separate from the independent evolutionary origins of hematophagy in sand flies (Psychodidae), tsetse flies (Glossinidae), screwworms (Calliphoridae), and stable flies (Muscidae) [69].…”

“…Our data revealed Culicoides cso-miR-956 was enriched in midgut tissues. In miRBase, miR-956 is only described in Drosophila but has been reported in multiple Dipteran taxa, including Culicomorpha (Culicidae) and Calyptratae muscoids (Sarcophagidae and Calliphoridae) [49,[55][56][57][58]. Work on Drosophila has alluded to multiple potential functions of miR-956, as this miRNA is thought to regulate the circadian rhythm [59] and has been recently shown to have a role in intestinal cell differentiation [60].…”