Search results for "Drosophila."

Oxidative modification impairs SERCA activity in Drosophila and human cell models of Parkinson's disease

2021

DJ-1 is a causative gene for familial Parkinson's disease (PD) with different functions, standing out its role against oxidative stress (OS). Accordingly, PD model flies harboring a mutation in the DJ-1β gene (the Drosophila ortholog of human DJ-1) show high levels of OS markers like protein carbonylation, a common post-translational modification that may alter protein function. To increase our understanding of PD pathogenesis as well as to discover potential therapeutic targets for pharmacological intervention, we performed a redox proteomic assay in DJ-1β mutant flies. Among the proteins that showed increased carbonylation levels in PD model flies, we found SERCA, an endoplasmic reticulum…

Visual Working Memory Requires Permissive and Instructive NO/cGMP Signaling at Presynapses in the Drosophila Central Brain.

2017

The gaseous second messenger nitric oxide (NO) has been shown to regulate memory formation by activating retrograde signaling cascades from post- to presynapse that involve cyclic guanosine monophosphate (cGMP) production to induce synaptic plasticity and transcriptional changes. In this study, we analyzed the role of NO in the formation of a visual working memory that lasts only a few seconds. This memory is encoded in a subset of ring neurons that form the ellipsoid body in the Drosophila brain. Using genetic and pharmacological manipulations, we show that NO signaling is required for cGMP-mediated CREB activation, leading to the expression of competence factors like the synaptic homer pr…

Temperature-dependent small RNA expression in Drosophila melanogaster

2018

Temperature has a major impact on gene expression in ectotherms. But until recently, it was not clear in which way, if any, small non-coding RNAs such as miRNAs or piRNAs contribute to thermosensitive gene regulation. We have recently shown that temperature-responsive miRNAs in Drosophila drive adaptation to different ambient temperatures on the transcriptome level. Moreover, we demonstrated that higher temperatures lead to a more efficient piRNA-dependent transposon silencing, possibly due to heat-induced unfolding of RNA secondary structures. In this commentary, we will dwell upon particular interesting aspects connected to our findings, hoping that our point of view may encourage other s…

P/CAF-mediated spermidine acetylation regulates histone acetyltransferase activity

2016

Histones and polyamines are important determinants of the chromatin structure. Histones form the core of nucleosome particles and their modification by acetylation of N-terminal tails is involved in chromatin structural changes and transcriptional regulation. Polyamines, including spermidine, are also targets of both cytoplasmic and nuclear acetylation, which in turn alters their affinity for DNA and nucleosomes. Previous studies report the interplay between polyamines metabolism and levels of histone acetylation, but the molecular basis of this effect is still unclear. In this work, we have analyzed the in vitro effect of spermidine on histone H3 acetylation catalyzed by P/CAF, a highly co…

Simulation-based estimation of branching models for LTR retrotransposons

2017

Abstract Motivation LTR retrotransposons are mobile elements that are able, like retroviruses, to copy and move inside eukaryotic genomes. In the present work, we propose a branching model for studying the propagation of LTR retrotransposons in these genomes. This model allows us to take into account both the positions and the degradation level of LTR retrotransposons copies. In our model, the duplication rate is also allowed to vary with the degradation level. Results Various functions have been implemented in order to simulate their spread and visualization tools are proposed. Based on these simulation tools, we have developed a first method to evaluate the parameters of this propagation …

2018

Abstract To function properly, organisms must adjust their physiology, behavior and metabolism in response to a suite of varying environmental conditions. One of the central regulators of these changes is organisms’ internal circadian clock, and recent evidence has suggested that the clock genes are also important in the regulation of seasonal adjustments. In particular, thermosensitive splicing of the core clock gene timeless in a cosmopolitan fly, Drosophila melanogaster, has implicated this gene to be involved in thermal adaptation. To further investigate this link we examined the splicing of timeless in a northern malt fly species, Drosophila montana, which can withstand much colder cli…

ISWI ATP-dependent remodeling of nucleoplasmic ω-speckles in the brain of Drosophila melanogaster.

2017

Heterogeneous nuclear ribonucleoproteins (hnRNPs) belong to the RNA-binding proteins family. They are involved in processing heterogeneous nuclear RNAs (hnRNAs) into mature mRNAs. These proteins participate in every step of mRNA cycle, such as mRNA export, localization, translation, stability and alternative splicing. At least 14 major hnRNPs, which have structural and functional homologues in mammals, are expressed in Drosophila melanogaster. Until now, six of these hnRNPs are known to be nucleus-localized and associated with the long non-coding RNA (lncRNA) heat shock responsive ω (hsrω) in the omega speckle compartments (ω-speckles). The chromatin remodeler ISWI is the catalytic subunit …

Co-chaperone Hsp70/Hsp90-organizing protein (Hop) is required for transposon silencing and Piwi-interacting RNA (piRNA) biogenesis

2017

Piwi-interacting RNAs (piRNAs) are 26–30-nucleotide germ line-specific small non-coding RNAs that have evolutionarily conserved function in mobile genetic element (transposons) silencing and maintenance of genome integrity. Drosophila Hsp70/90-organizing protein homolog (Hop), a co-chaperone, interacts with piRNA-binding protein Piwi and mediates silencing of phenotypic variations. However, it is not known whether Hop has a direct role in piRNA biogenesis and transposon silencing. Here, we show that knockdown of Hop in the germ line nurse cells (GLKD) of Drosophila ovaries leads to activation of transposons. Hop GLKD females can lay eggs at the same rate as wild-type counterparts, but the e…

Octopamine Shifts the Behavioral Response From Indecision to Approach or Aversion in Drosophila melanogaster

2018

Animals must make constant decisions whether to respond to external sensory stimuli or not to respond. The activation of positive and/or negative reinforcers might bias the behavioral response towards approach or aversion. To analyze whether the activation of the octopaminergic neurotransmitter system can shift the decision between two identical odor sources, we active in Drosophila melanogaster different sets of octopaminergic neurons using optogenetics and analyze the choice of the flies using a binary odor trap assay. We show that the release of octopamine from a set of neurons and not acetylcholine acts as positive reinforcer for one food odor source resulting in attraction. The activat…

Luminance Information Is Required for the Accurate Estimation of Contrast in Rapidly Changing Visual Contexts.

2020

Summary Visual perception scales with changes in the visual stimulus, or contrast, irrespective of background illumination. However, visual perception is challenged when adaptation is not fast enough to deal with sudden declines in overall illumination, for example, when gaze follows a moving object from bright sunlight into a shaded area. Here, we show that the visual system of the fly employs a solution by propagating a corrective luminance-sensitive signal. We use in vivo 2-photon imaging and behavioral analyses to demonstrate that distinct OFF-pathway inputs encode contrast and luminance. Predictions of contrast-sensitive neuronal responses show that contrast information alone cannot ex…