Differentially expressed microRNAs associated with changes of transcript levels in detoxification pathways and DDT-resistance in the Drosophila melanogaster strain 91-R

Abstract

Dichloro-diphenyl-trichloroethane (DDT) resistance among arthropod species is a model for understanding the molecular adaptations in response to insecticide exposures. Previous studies reported that DDT resistance may involve one or multiple detoxification genes, such as cytochrome P450 monooxygenases (P450s), glutathione S-transferases (GSTs), esterases, and ATP binding cassette (ABC) transporters, or changes in the voltage-sensitive sodium channel. However, the possible involvement of microRNAs (miRNAs) in the post-transcriptional regulation of genes associated with DDT resistance in the Drosophila melanogaster strain 91-R remains poorly understood. In this study, the majority of the resulting miRNAs discovered in small RNA libraries from 91-R and the susceptible control strain, 91-C, ranged from 16–25 nt, and contained 163 precursors and 256 mature forms of previously-known miRNAs along with 17 putative novel miRNAs. Quantitative analyses predicted the differential expression of ten miRNAs between 91-R and 91-C, and, based on Gene Ontology and pathway analysis, these ten miRNAs putatively target transcripts encoding proteins involved in detoxification mechanisms. RT-qPCR validated an inverse correlation between levels of differentially-expressed miRNAs and their putatively targeted transcripts, which implies a role of these miRNAs in the differential regulation of detoxification pathways in 91-R compared to 91-C. This study provides evidence associating the differential expression of miRNAs in response to multigenerational DDT selection in Drosophila melanogaster and provides important clues for understanding the possible roles of miRNAs in mediating insecticide resistance traits.

Post-transcriptional modulation of cytochrome P450s, Cyp6g1 and Cyp6g2, by miR-310s cluster is associated with DDT-resistant Drosophila melanogaster strain 91-R

“…The possibility that the reduced expression of miR-310s in 91-R may impact a range of other genes cannot be ruled out. Computational predictions suggest putatively regulated transcripts encode a broad range of proteins, including a subset with functional annotation suggesting roles in xenobiotic detoxification 21 . Thus, the role of miR-310s in the DDT resistance phenotype may be more complex, and a future genome-wide transcriptome analysis of miR-310s mimics injected Drosophila samples could potentially provide a precise and unbiased measure of impact on target transcripts.…”

“…For example, the potential involvement of Cyp4g1 , Cyp6g1 , and Cyp12d1 in DDT resistance in 91-R was demonstrated via independent RNA interface (RNAi)-mediated knockdown of transcripts using the transgenic Gal4/UAS-RNAi expression system, each resulting in increased susceptibility 10 . Moreover, differences in micro-RNA (miRNA) repression of P450 transcription or translation was implicated within the polygenic DDT resistance mechanism of 91-R 11 , 21 . However, relatively little is known regarding the precise mechanism(s) by which P450s are silenced by miRNAs or the downstream effects on response to xenobiotic exposure in Drosophila .…”

“…In previous research, we identified miRNAs with significant levels of differential expression between Drosophila strains that are DDT-resistant ( 91-R ) and -susceptible ( 91-C ) 21 . The miR-310s were significantly down-regulated in the 91-R strain as compared to the 91-C strain and computational predictions identified a number of cytochrome P450 transcripts, including Cyp6g1 , Cyp6g2 , Cyp6w1 , Cyp49a1 , and Cyp12a5, as potential targets of these miR-310s 21 . However, empirical evidence to support these predicted regulatory roles of miR-310s in DDT resistance is currently lacking.…”

Transcription factors CncC/Maf and AhR/ARNT coordinately regulate the expression of multiple GSTs conferring resistance to chlorpyrifos and cypermethrin inSpodoptera exigua

“…Previous work has shown that overproduction of detoxification enzymes is an important mechanism for insecticide resistance and complex regulatory mechanisms are involved in the up‐regulated expression of resistance‐associated detoxification genes, such as cis ‐regulatory elements and/or trans ‐acting factors, microRNAs and GPCR signaling cascades . The up‐regulation of CYP6FU1 conferring deltamethrin resistance in Laodelphax striatellus involves multiple cis ‐regulatory elements .…”

MicroRNA targeting of the non‐canonical planar cell polarity pathway in the developing neural tube

“…During embryogenesis, DE miRNAs directly govern critical developmental events, whereas constitutively expressed miRNAs most likely fine tune and maintain the basal gene expression levels. 47,48 We have thus focused our analyses in the current study on DE miRNAs in the developing murine NT. Bioinformatic analyses utilizing IPA, miRDB and TargetScan databases revealed that several DE miRNAs target the mRNA products of a range of genes encoding members of the PCP pathway ( Table 2).…”