Changes in microRNA abundance may regulate diapause in the flesh fly, Sarcophaga bullata

Abstract

Diapause, an alternative developmental pathway characterized by changes in developmental timing and metabolism, is coordinated by molecular mechanisms that are not completely understood. MicroRNA (miRNA) mediated gene silencing is emerging as a key component of animal development and may have a significant role in initiating, maintaining, and terminating insect diapause. In the present study, we test this possibility by using high-throughput sequencing and qRT-PCR to discover diapause-related shifts in miRNA abundance in the flesh fly, Sarcophaga bullata. We identified ten evolutionarily conserved miRNAs that were differentially expressed in diapausing pupae compared to their nondiapausing counterparts. miR-289-5p and miR-1-3p were overexpressed in diapausing pupae and may be responsible for silencing expression of candidate genes during diapause. miR-9c-5p, miR-13b-3p, miR-31a-5p, miR-92b-3p, miR-275-3p, miR-276a-3p, miR-277-3p, and miR-305-5p were underexpressed in diapausing pupae and may contribute to increased expression of heat shock proteins and other factors necessary for the enhanced environmental stress-response that is a feature of diapause. In S. bullata, a maternal effect blocks the programming of diapause in progeny of females that have experienced pupal diapause, and in this study we report that several miRNAs, including miR-263a-5p, miR-100-5p, miR-125-5p, and let-7-5p were significantly overexpressed in such nondiapausing flies and may prevent entry into diapause. Together these miRNAs appear to be integral to the molecular processes that mediate entry into diapause.

MicroRNAs are differentially abundant during Aedes albopictus diapause maintenance but not diapause induction

“…B, Table ). A recent study identified 10 differentially abundant miRNAs during the pupal diapause of S. bullata (Reynolds et al ., ) including miR‐1‐3p , one of the differentially abundant miRNAs identified in our study. In contrast to our results, miR‐1‐3p was more abundant in S. bullata during diapause relative to nondiapause, suggesting independent mechanisms of miRNA regulation of diapause in these two species.…”

“…Specifically, Loquacious , encoding a protein necessary for miRNA maturation, and Argonaute‐1 , encoding a protein in the miRNA‐induced silencing complex, are upregulated in diapause pupae of S. bullata (Reynolds et al ., ). Furthermore, 10 miRNAs were found to be differentially abundant during pupal diapause in S. bullata and subsequent in silico target prediction suggests these miRNAs could regulate development, stress tolerance and metabolism (Reynolds et al ., ). miRNAs also contribute to maintenance and termination of the dauer arrest in Caenorhabditis elegans , a diapause‐like state in worms (Karp et al ., ; Karp & Ambros, ).…”

Transcriptomic analysis of maternally provisioned cues for phenotypic plasticity in the annual killifish, Austrofundulus limnaeus

“…Recent studies suggest diapause-specific miRNAs in flesh flies as well [96]. In addition, miRNAs are critical for reactivation of delayed implanting mouse embryos [97, 98].…”

Seasonal phenotype‐specific expression of microRNAs during metamorphosis in the European map butterfly Araschnia levana

“…miRNAs mainly exert a negative effect on gene expression, raising the possibility that they play a role in inhibiting genes that can negatively influence the formation of polyphenic morphs in A. levana in response to changing environmental clues. Interestingly, Reynolds, Peyton, and Denlinger (2017) previously identified several miRNAs, which were differentially expressed in diapausing versus developing fly pupae of the flesh fly, Sarcophaga bullata . Among those, miR‐289‐5p was overexpressed in diapausing pupae compared to their nondiapausing counterparts.…”