The peculiarities of piRNA expression upon heat shock exposure inDrosophila melanogaster

Abstract

Different types of stress including heat shock may induce genomic instability, due to the derepression and amplification of mobile elements (MEs). It remains unclear, however, whether piRNA-machinery regulating ME expression functions normally under stressful conditions. The aim of this study was to explore the features of piRNA expression after heat shock (HS) exposure in Drosophila melanogaster. We also evaluated functioning of piRNAmachinery in the absence of major stress protein Hsp70 in this species. We analyzed the deep sequence data of piRNA expression after HS treatment and demonstrated that it modulates the expression of certain double-stranded germinal piRNA-clusters. Notable, we demonstrated significant changes in piRNA levels targeting a group of MEs after HS only in the strain containing normal set of hsp70 genes. Surprisingly, we failed to detect any correlation between the levels of piRNAs and the transcription of complementary MEs in the studied strains. We propose that modulation of certain piRNA-clusters expression upon HS exposure in D. melanogaster occurs due to HS-induced altering of chromatin state at certain chromosome regions.

Interplay between RNA interference and heat shock response systems in Drosophila melanogaster

“…Pre-processing and mapping of small RNA libraries to the dm3 Drosophila genome assembly was performed as previously described [27]. The number of reads mapped to the miRNAs was counted, using the B ed T ools toolkit (v. 2.22) and miRBase (r.19) annotation [53].…”

“…We performed this analysis using a D. melanogaster ‘hsp70 − strain’ that lacks all hsp70 genes [26]. Recently, using the same model system, we analysed the deep-sequencing data of piRNA expression after HS treatment and demonstrated that HS results in strain-specific expression modulation of certain double-stranded piRNA clusters [27]. …”

Reprogramming of Small Noncoding RNA Populations in Peripheral Blood Reveals Host Biomarkers for Latent and Active Mycobacterium tuberculosis Infection

“…tuberculosis infection have been suggested to be a possible bacterial evasion mechanism (42, 43), which might explain the different piRNA signatures identified here. Another plausible explanation is that piRNA are simply dysregulated upon cellular stress (44). However, very little is known about the full spectrum of piRNA functions beyond the original concept that they interfere with replication of endogenous retroviruses in germ line cells.…”

Germline silencing of UASt depends on the piRNA pathway

“…2001). A previous study proposed the possible involvement of Hsp70 in the biogenesis of piRNA in Drosophila following severe heat-shock conditions, but could not conclusively determine the details of this regulatory process (Funikov et al 2015). This, in combination with our findings, suggest that piRNAs may be involved in the heat-stress induced response mediated by increased Hsp70 levels for normal development.…”