Male Drosophila Research Articles

Functional role of the c-terminal domains of the msl2 protein of drosophila melanogaster

Dosage compensation complex, consisting of five proteins and two non-coding RNAs roX, specifically binds to the X chromosome in males, providing a higher level of gene expression, which is necessary to compensate for the monosomy of the sex chromosome in male Drosophila compared to two X chromosomes in females. The MSL2 protein contains an N-terminal RING domain, which acts as an E3 ligase in the ubiquitination of proteins and is the only subunit of the complex that is expressed only in males. The functional role of two C-terminal domains of the MSL2 protein, enriched with proline (P-domain) and basic amino acids (B-domain), was investigated. As a result, it was shown that the B-domain destabilizes the MSL2 protein, which is associated with the presence of two lysines whose ubiquitination is under the control of the RING domain of MSL2. The unstructured proline-rich domain stimulates transcription of the roX2 gene, which is necessary for the effective formation of the dosage compensation complex.

Genetic Screening Reveals Cone Cell-Specific Factors as Common Genetic Targets Modulating Rival-Induced Prolonged Mating in male Drosophila melanogaster.

Male-male social interactions exert a substantial impact on the transcriptional regulation of genes associated with aggression and mating behavior in male Drosophila melanogaster. Throughout our comprehensive genetic screening of aggression-related genes, we identified that the majority of mutants for these genes are associated with rival-induced and visually-oriented mating behavior, longer-mating-duration (LMD). The majority of mutants with upregulated genes in single-housed males significantly altered LMD behavior but not copulation latency, suggesting a primary regulation of mating duration. Single-cell RNA sequencing revealed that LMD-related genes are predominantly co-expressed with male-specific genes like dsx and Cyp6a20 in specific cell populations, especially in cone cells. Functional validation confirmed the roles of these genes in mediating LMD. Expression of LMD genes like Cyp6a20, Cyp4d21, and CrzR was enriched in cone cells, with disruptions in cone cell-specific expression of CrzR and Cyp4d21 leading to disrupted LMD. We also identified a novel gene, CG10026/Macewindu, that reversed LMD when overexpressed in cone cells. These findings underscore the critical role of cone cells as a pivotal site for the expression of genes involved in the regulation of LMD behavior. This study provides valuable insights into the intricate mechanisms underlying complex sexual behaviors in Drosophila.

Convergent olfactory circuits for courtship in Drosophila revealed by ds -Tango.

Animals exhibit sex-specific behaviors that are governed by sexually dimorphic circuits. One such behavior in male Drosophila melanogaster , courtship, is regulated by various sensory modalities, including olfaction. Here, we reveal how sexually dimorphic olfactory pathways in male flies converge at the third-order, onto lateral horn output neurons, to regulate courtship. To achieve this, we developed ds -Tango, a modified version of the monosynaptic tracing and manipulation tool trans- Tango. In ds -Tango, two distinct configurations of trans- Tango are positioned in series, thus providing selective genetic access not only to the monosynaptic partners of starter neurons but also to their disynaptic connections. Using ds -Tango, we identified a node of convergence for three sexually dimorphic olfactory pathways. Silencing this node results in deficits in sex recognition of potential partners. Our results identify lateral horn output neurons required for proper courtship behavior in male flies and establish ds -Tango as a tool for disynaptic circuit tracing.

Analysis of potential genotoxicity of deicing material in the test for induction of dominant lethal mutations in germ cells of male Drosophila

Introduction. Long-term use of deicing materials (DM) is one of the significant factors causing the active distribution of various chemical compounds that are part of multicomponent deicing mixtures in the environment. In this regard, the expansion of methodological approaches to assessing their biological hazard remains important. Materials and methods. The DM used for research based on a mixture of urea with magnesium and ammonium nitrates. The DM was tested in the form of an aqueous solution and added to the soil to obtain an aqueous extract. The analysis includes test for induced dominant lethal mutations in Drosophila male germ cells. Results. All samples tested significantly reduced the fertility of Drosophila males. The frequencies of early dominant lethal mutations (EDLM) significantly exceeded the levels of the controls, and the effects of the soil extract appeared at the lowest concentration – 5 g/L and of the DM solution – 10 g/L. The trend in the rate of late dominant lethal mutations (LDLM) indicates to the death of sperm or a decrease in mating potency. Limitations. The method of inducing dominant lethal mutations in Drosophila melanogaster and the genotoxic effects assessment of DM in the germ cells of male flies within the study has no restrictions. Conclusion. The conducted test is so far the only one in the field of research into the genetic safety of multicomponent DMs using a method for induced dominant lethal mutations in Drosophila male germ cells. The results prove the high informative rate of the methodological approach which involves analyzing soil extracts to identify and assess a genotoxicity of DM component composition when it enters the soil which can become as a transit layer for migration of DM components and their products transformation into groundwater.

Stimulus duration encoding occurs early in the moth olfactory pathway

Pheromones convey rich ethological information and guide insects’ search behavior. Insects navigating in turbulent environments are tasked with the challenge of coding the temporal structure of an odor plume, obliging recognition of the onset and offset of whiffs of odor. The coding mechanisms that shape odor offset recognition remain elusive. We designed a device to deliver sharp pheromone pulses and simultaneously measured the response dynamics from pheromone-tuned olfactory receptor neurons (ORNs) in male moths and Drosophila. We show that concentration-invariant stimulus duration encoding is implemented in moth ORNs by spike frequency adaptation at two time scales. A linear-nonlinear model fully captures the underlying neural computations and offers an insight into their biophysical mechanisms. Drosophila use pheromone cis-vaccenyl acetate (cVA) only for very short distance communication and are not faced with the need to encode the statistics of the cVA plume. Their cVA-sensitive ORNs are indeed unable to encode odor-off events. Expression of moth pheromone receptors in Drosophila cVA-sensitive ORNs indicates that stimulus-offset coding is receptor independent. In moth ORNs, stimulus-offset coding breaks down for short ( < 200 ms) whiffs. This physiological constraint matches the behavioral latency of switching from the upwind surge to crosswind cast flight upon losing contact with the pheromone.

Fertility loss and recovery dynamics after repeated heat stress across life stages in male Drosophila melanogaster: patterns and processes.

Frequent and extreme temperatures associated with climate change pose a major threat to biodiversity, particularly for organisms whose metabolism is strictly linked to ambient temperatures. Many studies have explored thermal effects on survival, but heat-induced fertility loss is emerging as a greater threat to population persistence. However, while evidence is accumulating that both juvenile and adult stages heat exposure can impair fertility in their own ways, much less is known about the immediate and longer-term fitness consequences of repeated heat stress across life stages. To address this knowledge gap, we used male Drosophila melanogaster to investigate (i) the cumulative fitness effects of repeated heat stress across life stages, (ii) the potential of recovery from these heat exposures, and (iii) the underlying mechanisms. We found individual and combined effects of chronic juvenile and acute adult heat stress on male fitness traits. These effects tended to exacerbate over several days after brief heat exposure, indicating a substantial fertility loss for these short-lived organisms. Our findings highlight the cumulative and persistent effects of heat stress on fitness. Such combined effects could accelerate population declines, particularly in more vulnerable species, emphasizing the importance of considering reproduction and its recovery for more accurate models of species persistence.

Heating alters the nutritional and antioxidant characteristics of lotus root

To investigate the impact of heating on the nutritional and antioxidant properties of lotus root, a comparative analysis was conducted between its heated and unheated whole powders. The whole powder of heated lotus root (HLRWP) exhibited a higher level of total soluble sugars but a lower level of free phenolic compounds compared to the whole powder of fresh lotus root (FLRWP). Meanwhile, they showed significant differences in metabolite composition encompassing phenolic compounds, flavonoids, amino acids, vitamins and lipids. The replacement of sugar and corn in the medium with 25% HLRWP effectively enhanced the activities of antioxidant enzymes (total superoxide dismutase and catalase), while reducing malonaldehyde content in Drosophila melanogaster males. The average, median and maximum lifespans of the fruit flies were extended by 35.90%, 23.49% and 24.00% respectively, accompanied by an improvement in climbing ability. Additionally, their resistance to oxidative stress induced by hydrogen peroxide or paraquat was enhanced. The antioxidant capacity of HLRWP in vivo was found to be obviously stronger compared to FLRWP, which may have a crucial association with the regulation of L-arginine and adenosine monophosphate levels. The results indicate that heating can enhance the nutritional quality of lotus root products by strengthening their antioxidant capacity.

Mating proximity blinds threat perception

Romantic engagement can bias sensory perception. This ‘love blindness’ reflects a common behavioural principle across organisms: favouring pursuit of a coveted reward over potential risks1. In the case of animal courtship, such sensory biases may support reproductive success but can also expose individuals to danger, such as predation2,3. However, how neural networks balance the trade-off between risk and reward is unknown. Here we discover a dopamine-governed filter mechanism in male Drosophila that reduces threat perception as courtship progresses. We show that during early courtship stages, threat-activated visual neurons inhibit central courtship nodes via specific serotonergic neurons. This serotonergic inhibition prompts flies to abort courtship when they see imminent danger. However, as flies advance in the courtship process, the dopaminergic filter system reduces visual threat responses, shifting the balance from survival to mating. By recording neural activity from males as they approach mating, we demonstrate that progress in courtship is registered as dopaminergic activity levels ramping up. This dopamine signalling inhibits the visual threat detection pathway via Dop2R receptors, allowing male flies to focus on courtship when they are close to copulation. Thus, dopamine signalling biases sensory perception based on perceived goal proximity, to prioritize between competing behaviours.

Betahistine mesylate reduces the damage of blue light exposure in Drosophila model

Previous studies have demonstrated the efficacy of betahistine mesylate in treating vertigo and angioneurotic headache, enhancing microcirculation, and facilitating histamine release. However, limited research has been conducted on the drug's potential in mitigating blue light-induced damage. Thus, this study utilized Drosophila as the model organism and employed the Siler model to investigate the impact of various concentrations of betahistine mesylate on the lifespan, under 3000 lx blue light irradiation. At the same time we measure food intake, spontaneous activity, and sleep duration of Drosophila. The findings of this study indicate that a high concentration of betahistine mesylate can decrease the initial mortality (b0) in male flies, mitigating the damage of blue light to Drosophila. Consequently, this delays the aging process in male Drosophila and extends their average lifespan. After betahistine mesylate ingestion, locomotor activity upon blue light exposure decreased significantly in male Drosophila. In conclusion, this study offers initial evidence supporting the investigation of the regulatory mechanisms of betahistine mesylate on lifespan and its potential anti-blue light effects.

Y chromosome genes interplay with interval timing in regulating mating duration of male Drosophila melanogaster

We explore the understudied role of Y chromosome genes in modulating mating behaviors and interval timing in male fruit flies. Our findings reveal a significant impact of these genes on mating duration, a critical aspect of sexual selection and reproductive success. Through the use of XO males lacking a Y chromosome and RNA interference (RNAi) techniques to knockdown specific Y chromosome genes, we demonstrate that the Y chromosome and its genes WDY and CCY are essential for the generation of Longer-Mating-Duration (LMD) and Shorter-Mating-Duration (SMD) behaviors. Notably, the neuronal knockdown of Ppr-Y, a gene highly expressed in both neuronal and glial cells, leads to profound disruptions in courtship and mating behaviors without affecting fertility. Utilizing the fly SCope scRNA-seq data platform, we identified that several Y chromosome genes, including kl-3, kl-5, WDY, and PRY, are preferentially expressed in fru-positive neurons, suggesting a role in male-specific neuronal populations. Our work not only advances the understanding of the Y chromosome's contribution to complex mating behaviors but also sets the stage for future investigations into the molecular mechanisms underlying sexual dimorphism and reproductive strategies in Drosophila.

The genome sequence of a drosophilid fruit fly, Drosophila helvetica Burla 1948

We present a genome assembly from an individual male Drosophila helvetica (drosophilid fruit fly; Arthropoda; Insecta; Diptera; Drosophilidae). The genome sequence spans 224.20 megabases. Most of the assembly is scaffolded into 6 chromosomal pseudomolecules, including the X and Y sex chromosomes. The mitochondrial genome has also been assembled and is 15.96 kilobases in length.

Peer-induced quiescence of male Drosophila melanogaster following copulation.

Mating experience impacts the physiology and behavior of animals. Although mating effects of female Drosophila melanogaster have been studied extensively, the behavioral changes of males following copulation have not been fully understood. In this study, we characterized the mating-dependent behavioral changes of male flies, especially focusing on fly-to-fly interaction, and their dependence on rearing conditions. Our data demonstrate that male flies quiesce their courtship toward both females and males, as well as their locomotor activity. This post-copulatory quiescence appears to be contingent upon the presence of a peer, as minimal variation is noted in locomotion when the male is measured in isolation. Interestingly, copulated males influence a paired male without successful copulation to reduce his locomotion. Our findings point to a conditional behavioral quiescence following copulation, influenced by the presence of other flies.

The genome sequence of a drosophilid fruit fly, Drosophila limbata von Roser 1840.

We present a genome assembly from an individual male Drosophila limbata (drosophilid fruit fly; Arthropoda; Insecta; Diptera; Drosophilidae). The genome sequence is 233.5 megabases in span. Most of the assembly is scaffolded into 6 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 16.09 kilobases in length.

Integrating mRNA transcripts and genomic information into genomic prediction.

Genomic prediction has emerged as a pivotal technology for the genetic evaluation of livestock, crops, and for predicting human disease risks. However, classical genomic prediction methods face challenges in incorporating biological prior information such as the genetic regulation mechanisms of traits. This study introduces a novel approach that integrates mRNA transcript information to predict complex trait phenotypes. To evaluate the accuracy of the new method, we utilized a Drosophila population that is widely employed in quantitative genetics researches globally. Results indicate that integrating mRNA transcript data can significantly enhance the genomic prediction accuracy for certain traits, though it does not improve phenotype prediction accuracy for all traits. Compared with GBLUP, the prediction accuracy for olfactory response to dCarvone in male Drosophila increased from 0.256 to 0.274. Similarly, the accuracy for cafe in male Drosophila rose from 0.355 to 0.401. The prediction accuracy for survival_paraquat in male Drosophila is improved from 0.101 to 0.138. In female Drosophila, the accuracy of olfactory response to 1hexanol increased from 0.147 to 0.210. In conclusion, integrating mRNA transcripts can substantially improve genomic prediction accuracy of certain traits by up to 43%, with range of 7% to 43%. Furthermore, for some traits, considering interaction effects along with mRNA transcript integration can lead to even higher prediction accuracy.

Synergistic Enhancement of Motor Function by Curcumin and Piperine in Alpha-Synuclein Expressing Drosophila Models

Parkinson’s disease (PD) is a neurodegenerative disease characterized by Lewy body formation mainly phosphorylated and aggregated α-synuclein, with subsequent neurotoxicity and death of dopaminergic neurons in the basal ganglia. The neuroprotective action of curcumin and piperine has been reported. We used the GAL4/UAS bipartite system for targeted expression of α-synuclein pan-neuronal and dopamine neurons to create genetically induced PD. Hence, in this study we assessed the ameliorative effect of curcumin and piperine on α-synuclein-induced dopaminergic neuron degeneration and photoreceptor degeneration in the Drosophila melanogaster model of PD. Male Drosophila melanogaster (upstream activating sequence (UAS) linked to synuclein (SNCA) flies were crossed with virgin wild-type Can-ton-S, DDC-GAL4 or GMR-GAL4 female flies) cultured on either medium containing graded concentrations of curcumin and/or piperine (5, 10, and 50 μM) or vehicle. The parameters measured included fecundity, larval motility, negative geotaxis, and lifespan. Vehicle, curcumin, or piperine supplementation in SNCA&gt;Cs, SNCA&gt;DDC, or SNCA&gt;GMR flies did not affect fecundity or larval motility, but piperine (5 μM and 10 μM but not 50 μM) supplementation reduced fecundity. SNCA&gt;DDC flies significantly reduced climbing performance and lifespan, peaked in week 4, ameliorated by the curcumin and piperine combination. Moreover, the increased aggregation of synuclein, as evidenced in ommatidial degeneration in SNCA&gt;GMR flies’ eyes, was attenuated by the curcumin and piperine combination. Findings from the present study further reinforced the potential benefit of curcumin and piperine in the management of PD.

Connectome-driven neural inventory of a complete visual system.

Vision provides animals with detailed information about their surroundings, conveying diverse features such as color, form, and movement across the visual scene. Computing these parallel spatial features requires a large and diverse network of neurons, such that in animals as distant as flies and humans, visual regions comprise half the brain's volume. These visual brain regions often reveal remarkable structure-function relationships, with neurons organized along spatial maps with shapes that directly relate to their roles in visual processing. To unravel the stunning diversity of a complex visual system, a careful mapping of the neural architecture matched to tools for targeted exploration of that circuitry is essential. Here, we report a new connectome of the right optic lobe from a male Drosophila central nervous system FIB-SEM volume and a comprehensive inventory of the fly's visual neurons. We developed a computational framework to quantify the anatomy of visual neurons, establishing a basis for interpreting how their shapes relate to spatial vision. By integrating this analysis with connectivity information, neurotransmitter identity, and expert curation, we classified the ~53,000 neurons into 727 types, about half of which are systematically described and named for the first time. Finally, we share an extensive collection of split-GAL4 lines matched to our neuron type catalog. Together, this comprehensive set of tools and data unlock new possibilities for systematic investigations of vision in Drosophila, a foundation for a deeper understanding of sensory processing.

Genomic context-dependent histone H3K36 methylation by three Drosophila methyltransferases and implications for dedicated chromatin readers.

Methylation of histone H3 at lysine 36 (H3K36me3) marks active chromatin. The mark is interpreted by epigenetic readers that assist transcription and safeguard the integrity of the chromatin fiber. The chromodomain protein MSL3 binds H3K36me3 to target X-chromosomal genes in male Drosophila for dosage compensation. The PWWP-domain protein JASPer recruits the JIL1 kinase to active chromatin on all chromosomes. Unexpectedly, depletion of K36me3 had variable, locus-specific effects on the interactions of those readers. This observation motivated a systematic and comprehensive study of K36 methylation in a defined cellular model. Contrasting prevailing models, we found that K36me1, K36me2 and K36me3 each contribute to distinct chromatin states. A gene-centric view of the changing K36 methylation landscape upon depletion of the three methyltransferases Set2, NSD and Ash1 revealed local, context-specific methylation signatures. Set2 catalyzes K36me3 predominantly at transcriptionally active euchromatin. NSD places K36me2/3 at defined loci within pericentric heterochromatin and on weakly transcribed euchromatic genes. Ash1 deposits K36me1 at regions with enhancer signatures. The genome-wide mapping of MSL3 and JASPer suggested that they bind K36me2 in addition to K36me3, which was confirmed by direct affinity measurement. This dual specificity attracts the readers to a broader range of chromosomal locations and increases the robustness of their actions.

Mapping model units to visual neurons reveals population code for social behaviour

The rich variety of behaviours observed in animals arises through the interplay between sensory processing and motor control. To understand these sensorimotor transformations, it is useful to build models that predict not only neural responses to sensory input1–5 but also how each neuron causally contributes to behaviour6,7. Here we demonstrate a novel modelling approach to identify a one-to-one mapping between internal units in a deep neural network and real neurons by predicting the behavioural changes that arise from systematic perturbations of more than a dozen neuronal cell types. A key ingredient that we introduce is ‘knockout training’, which involves perturbing the network during training to match the perturbations of the real neurons during behavioural experiments. We apply this approach to model the sensorimotor transformations of Drosophila melanogaster males during a complex, visually guided social behaviour8–11. The visual projection neurons at the interface between the optic lobe and central brain form a set of discrete channels12, and prior work indicates that each channel encodes a specific visual feature to drive a particular behaviour13,14. Our model reaches a different conclusion: combinations of visual projection neurons, including those involved in non-social behaviours, drive male interactions with the female, forming a rich population code for behaviour. Overall, our framework consolidates behavioural effects elicited from various neural perturbations into a single, unified model, providing a map from stimulus to neuronal cell type to behaviour, and enabling future incorporation of wiring diagrams of the brain15 into the model.

Misregulation of bromotyrosine compromises fertility in male Drosophila

Biological regulation often depends on reversible reactions such as phosphorylation, acylation, methylation, and glycosylation, but rarely halogenation. A notable exception is the iodination and deiodination of thyroid hormones. Here, we report detection of bromotyrosine and its subsequent debromination during Drosophila spermatogenesis. Bromotyrosine is not evident when Drosophila express a native flavin-dependent dehalogenase that is homologous to the enzyme responsible for iodide salvage from iodotyrosine in mammals. Deletion or suppression of the dehalogenase-encoding condet (cdt) gene in Drosophila allows bromotyrosine to accumulate with no detectable chloro- or iodotyrosine. The presence of bromotyrosine in the cdt mutant males disrupts sperm individualization and results in decreased fertility. Transgenic expression of the cdt gene in late-staged germ cells rescues this defect and enhances tolerance of male flies to bromotyrosine. These results are consistent with reversible halogenation affecting Drosophila spermatogenesis in a process that had previously eluded metabolomic, proteomic, and genomic analyses.

Sex-specific transgenerational effects of diet on offspring life history and physiology.

Dietary variation in males and females can shape the expression of offspring life histories and physiology. However, the relative contributions of maternal and paternal dietary variation to phenotypic expression of latter generations is currently unknown. We provided male and female Drosophila melanogaster grandparents with diets differing in sucrose concentration prior to reproduction, and similarly subjected their grandoffspring to the same treatments. We then investigated the phenotypic consequences of this dietary variation among the grandsons and granddaughters. We observed transgenerational effects of dietary sucrose, mediated through the grandmaternal lineage, which mimic the direct effects of sucrose on lifespan, with opposing patterns across sexes; low sucrose increased female, but decreased male, lifespan. Dietary mismatching of grandoffspring-grandparent diets increased lifespan and reproductive success, and moderated triglyceride levels of grandoffspring, providing insights into the physiological underpinnings of the complex transgenerational effects on life histories.