Induction and suppression of NF-κB signalling by a DNA virus of <i>Drosophila</i>

Contains fulltext : 200878.pdf (Publisher’s version ) (Open Access)20 p

Viral piRNA profiles.

<p>piRNA distributions across the genomes of selected (A) alphaviruses, (B) flaviviruses, and (C) bunyaviruses. The plots depict published genome profiles of Sindbis virus (SINV) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref029" target="_blank">29</a>], chikungunya virus (CHIKV) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref030" target="_blank">30</a>], Semliki Forest virus (SFV) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref031" target="_blank">31</a>], dengue virus serotype 2 (DENV2) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref035" target="_blank">35</a>,<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref036" target="_blank">36</a>], cell fusing agent virus (CFAV) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref034" target="_blank">34</a>], Rift Valley fever virus (RVFV) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref038" target="_blank">38</a>], and Schmallenberg virus (SBV) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006017#ppat.1006017.ref037" target="_blank">37</a>]. For alphaviruses, the position of the subgenomic promoter is depicted. The piRNA coverage on the sense or antisense strand is shown as peaks above or below the <i>x</i>-axis, respectively. Please note that the plots are representations of piRNA profiles from multiple studies that used different ways of normalizing and presenting read counts. Therefore, the heights of the bars are arbitrary and do not allow a quantitative comparison between the different viruses.</p

An ancient satellite repeat controls gene expression and embryonic development in Aedes aegypti through a highly conserved piRNA

Article publié sous le titre "A satellite repeat-derived piRNA controls embryonic development of Aedes"International audienceTandem repeat elements such as the diverse class of satellite repeats occupy large parts of eukaryotic chromosomes, mostly at centromeric, pericentromeric, telomeric and subtelomeric regions1. However, some elements are located in euchromatic regions throughout the genome and have been hypothesized to regulate gene expression in cis by modulating local chromatin structure, or in trans via transcripts derived from the repeats2-4. Here we show that a satellite repeat in the mosquito Aedes aegypti promotes sequence-specific gene silencing via the expression of two PIWI-interacting RNAs (piRNAs). Whereas satellite repeats and piRNA sequences generally evolve extremely quickly5-7, this locus was conserved for approximately 200 million years, suggesting that it has a central function in mosquito biology. piRNA production commenced shortly after egg laying, and inactivation of the more abundant piRNA resulted in failure to degrade maternally deposited transcripts in the zygote and developmental arrest. Our results reveal a mechanism by which satellite repeats regulate global gene expression in trans via piRNA-mediated gene silencing that is essential for embryonic development

Improved Stress Control in Serotonin Transporter Knockout Rats: Involvement of the Prefrontal Cortex and Dorsal Raphe Nucleus

Variations in serotonin transporter (5-HTT) expression have been associated with altered sensitivity to stress. Since controllability is known to alter the impact of a stressor through differential activation of the medial prefrontal cortex (mPFC) and dorsal raphe nucleus (DRN), and that these regions are functionally affected by genetic 5-HTT down-regulation, we hypothesized that 5-HTT expression modulates the effect of controllability on stressor impact and coping. Here, we investigated the effects of a signaled stress controllability task or a yoked uncontrollable stressor on behavioral responding and mPFC and DRN activation. 5-HTT^–/– rats proved better capable of acquiring the active avoidance task than 5-HTT^+/+ animals. Controllability determined DRN activation in 5-HTT^+/+, but not 5-HTT^–/–, rats, whereas controllability-related activation of the mPFC was independent of genotype. These findings suggest that serotonergic activation in the DRN is involved in stress coping in a 5-HTT expression dependent manner, whereas mPFC activation seems to be implicated in control over stress independently of 5-HTT expression. We speculate that alterations in serotonergic feedback in the DRN might be a potential mechanism driving this differential stress coping

The beauty and complexity of the small heat shock proteins: a report on the proceedings of the fourth workshop on small heat shock proteins.

The Fourth Cell Stress Society International workshop on small heat shock proteins (sHSPs), a follow-up to successful workshops held in 2014, 2016 and 2018, took place as a virtual meeting on the 17-18 November 2022. The meeting was designed to provide an opportunity for those working on sHSPs to reconnect and discuss their latest work. The diversity of research in the sHSP field is reflected in the breadth of topics covered in the talks presented at this meeting. Here we summarise the presentations at this meeting and provide some perspectives on exciting future topics to be addressed in the field