Identification and characterization of stage-specific and sex-specific micro-rnas of Glossina pallidipes tsetse fly, vector of African trypanosomiasis

Abstract

The field of miRNA biology is tremendously growing, moreover, their roles of regulating a wide array of cell function is extensive. The importance of miRNAs in development has become nearly ubiquitous, with miRNA contributing to development of most cells and organs. Although miRNAs are clearly interwoven into known regulatory networks that control cell development, the specific modalities by which they intersect are often quite distinct in different organism. In insect species miRNA involved in development has been well study in Drosphila spp and Anopheles spp. However, information concerning possible developmental role of miRNAs in tsetse is limited. Hence, the aim of the study is to identify and characterize miRNA genes in the developmental cycle of G. pallidipes. Firstly, the small RNAs from the five developmental stages (larvae, pupae, teneral adults, non-teneral adults and gravid females) were sequenced using next generation sequencing technology. A total of 157 miRNAs were identified, which included 99 known tsetse miRNAs, 46 miRNAs conserved in other insects, and 12 novel miRNAs that had not been reported in any species. Moreover, we identified 93 miRNA genes that were differentially expressed by sex and/or in specific developmental stages. Hence, the 5550 target genes for the differentially expressed genes were identified using miRanda and RNAhyrid. Functional annotations using Blast2GO yielded KEGG pathways: Purine metabolism (n = 183), Thiamine metabolism (n = 163), Biosynthesis of antibiotics (n = 55), Aminoacyl-tRNA biosynthesis (n = 16), Pyruvate metabolism (n = 13), Pyrimidine metabolism (n = 12), Glycerophospholipid metabolism (n = 12), Amino sugar and nucleotide sugar metabolism (n = 11) and cysteine and methionine metabolism (n = 11). Also, gene ontology including, cellular process (n = 1464), metabolic process (n = 1383), cell part (n = 790), organelle (n = 609), membrane (n = 588), biological regulation (n = 467), localization (n = 398), response to stimulus (n= 285), cellular component organization or biogenesis (n = 222), and signalling (n = 218). The finding offers miRNA genes involved in the regulation of critical physiological functions specific towards G. pallidipes development, which could eventually guide other scientist in the use of miRNA genes as a combination of novel approaches and the available technique to combat tsetse-borne diseases.