Fly最新文献

Ribosomal protein (RP) gene haploinsufficiency is a conserved form of ribosome dysfunction across species and underlies a class of disorders known as ribosomopathies. In Drosophila, RP gene haploinsufficiency manifests as the Minute phenotype, characterized by thinner and shorter mechanosensory bristles. The development of both bristles and proprioceptive campaniform sensilla (CS) is initiated by the bHLH proneural proteins Achaete (Ac) and Scute (Sc). By analysing genetic interactions between ac sc mutants and Minute mutants of varying severity, we identified a novel bristle-promoting effect that occurs only in the strongly affected Minutes in which the average bristle length is shorter than a threshold. This threshold-dependent effect also promotes ectopic CS formation in the strong Minutes. Transcriptomic analyses comparing the sensory organ - promoting and non-promoting Minutes revealed significant differences in stress-response pathways, including differentially elevated expression of the Xrp1-Irbp18 transcriptional dimer. Notably, mutation of Xrp1 suppresses the ectopic CS phenotype, indicating a positive regulatory role. These findings reveal a previously unrecognized threshold effect in RP gene haploinsufficiency, in which excessive Xrp1 activity promotes supernumerary sensory organ formation, suggesting a compensatory mechanism that modulates neurogenesis under severe ribosomal stress.

Drosophila melanogaster Nora virus (DmNV), a positive-sense single stranded RNA virus related to picornaviruses. Given its genetic and structural similarity to neurotropic picornaviruses, such as poliovirus, we sought to determine whether DmNV could be found within the head and brain of D. melanogaster. RNA was extracted from heads of chronically DmNV-infected stocks, as well as from uninfected controls, and assayed using reverse transcription-polymerase chain reaction (RT-PCR) for DmNV open reading frame 1 (ORF1). The results showed that DmNV genomic material can be isolated from the heads of DmNV-infected D. melanogaster, which suggests that the virus reaches the head during the course of infection. To determine whether DmNV infects the brain tissue itself, small-molecule RNA fluorescence in situ hybridization (smRNA FISH) experiments on whole brains dissected from DmNV-infected and uninfected D. melanogaster were done. The smRNA FISH detection method was validated by identifying DmNV RNA in gut tissue, but there was no evidence of DmNV localization in any brain specimens examined. These findings suggest an alternative explanation for why DmNV may be present in dissected head specimens. Additionally, we highlight the effectiveness of smRNA FISH as a highly specific and accessible method for detecting RNA viruses in Drosophila, offering an alternative to antibody-based or transgenic fluorescence approaches. Together, our results refine the understanding of DmNV tissue tropism and provide methodological insights for future studies using insect RNA viruses.

Angelman syndrome (AS) is a rare neurogenetic disorder characterized by developmental delay, speech impairment, ataxia, epilepsy, and in some cases hyperphagic feeding behavior. AS is caused by loss of function mutations, loss of expression, or maternal allele deletion of the E3 ubiquitin ligase UBE3A. Recent work has identified a connection between UBE3A and the mechanosensitive ion channel PIEZO2, raising the possibility that UBE3A may regulate PIEZO-dependent satiety signaling. In this study, we investigated the role of the Drosophila UBE3A ortholog, Dube3a, in Piezo-associated feeding behaviors. Single-cell RNA-sequencing data revealed overlapping expression of Dube3a and Piezo within crop and enterocyte populations of the gut, identifying a relevant cellular context for this pathway to occur. We developed a novel feeding assay using GFP-expressing yeast to quantify food intake and gut distention in vivo. Dube3a loss-of-function (Dube3a^15b) flies exhibited hyperphagia and gut distention nearly identical to Piezo knockout flies. Analysis of chromosomal deficiency lines spanning the Dube3a locus further supported a requirement for Dube3a in normal satiety signaling. Finally, biochemical analyses demonstrated that Dube3a knockdown results in decreased Piezo protein levels, consistent with an indirect regulatory relationship. Together, these findings identify Dube3a as a critical regulator of Piezo-dependent satiety pathways and suggest that dysregulation of mechanosensory signaling may contribute to hyperphagia observed in AS. Further work is needed to define the intermediate factors linking UBE3A activity to Piezo stability and function.

Drosophila melanogaster is a highly versatile model organism that has profoundly advanced our understanding of human diseases. With more than 60% of its genes having human homologs, Drosophila provides an invaluable system for modelling a wide range of pathologies, including neurodegenerative disorders, cancer, metabolic diseases, as well as cardiac and muscular conditions. This review highlights key developments in utilizing Drosophila for disease modelling, emphasizing the genetic tools that have transformed research in this field. Technologies such as the GAL4/UAS system, RNA interference (RNAi) and CRISPR-Cas9 have enabled precise genetic manipulation, with CRISPR-Cas9 allowing for the introduction of human disease mutations into orthologous Drosophila genes. These approaches have yielded critical insights into disease mechanisms, identified novel therapeutic targets and facilitated both drug screening and toxicological studies. Articles were selected based on their relevance, impact and contribution to the field, with a particular focus on studies offering innovative perspectives on disease mechanisms or therapeutic strategies. Our findings emphasize the central role of Drosophila in studying complex human diseases, underscoring its genetic similarities to humans and its effectiveness in modelling conditions such as Alzheimer's disease, Parkinson's disease and cancer. This review reaffirms Drosophila's critical role as a model organism, highlighting its potential to drive future research and therapeutic advancements.

Three decades of research aimed at understanding the basis for autosomal recessive primary microcephaly (MCPH), a human clinical disorder defined by a significant reduction in head and brain size, has uncovered a suite of ~30 genes that participate in this process. Work in both vertebrate and invertebrate model systems have been instrumental in attempting to link MCPH gene function to the brain growth phenotype. However, we still lack definitive evidence as to what these functions are for many of these genes. In this review, we summarize recent work in Drosophila aimed at overcoming these limitations in our knowledge of MCPH gene function that may be applicable to humans. We discuss the clinical features of MCPH, parallels between human and Drosophila neurogenesis modes with a particular focus on the fly optic lobe, and highlight four of the most well-studied Drosophila MCPH orthologs: abnormal spindle (asp)/MCPH5, Microcephalin/MCPH1, WD Repeat-Containing Protein 62 (Wdr62)/MCPH2, and Ankryin Repeat-and LEM Domain- Containing Protein 2 (ANKLE2)/MCPH16. We focus on the multifunctional roles for these proteins that may underlie the microcephaly phenotype and advocate for the use of flies as a relevant model for human MCPH.

UCH-L1 (Ubiquitin Carboxyl-terminal Hydrolase - L1) is a protein that plays a critical role in the ubiquitin-proteasome system. Previous studies have demonstrated a link between UCH-L1 and various diseases, including neurodegenerative disorders, diabetes, and cancer. However, the role of UCH-L1 in development remains unclear. To investigate the functions of UCH-L1 in a living organism, taking advantage of the Drosophila model, and to explore the correlation between Drosophila UCH (dUCH) and human UCH-L1, we established a GAL4/UAS-targeted expression system to examine the effect of dUCH on Drosophila eye development. We found that knockdown of dUCH resulted in a rough eye phenotype associated with the MAPK pathway. In this study, for the first time, we revealed that loss of dUCH function leads to a reduction in EGFR protein levels. Additionally, dUCH knockdown downregulated Spitz (spi), a ligand of EGFR, as well as Draf, a key component of the MAPK pathway. Furthermore, under dUCH knockdown conditions, several genes known to play critical roles in eye cell differentiation were affected, including the downregulation of sens, salm, lz, barth1/2, and salm, which are essential for the differentiation of R2/5, R3/4, and R1/6 photoreceptor cells. Interestingly, dUCH was found to be involved not only in the MAPK pathway but also in the regulation of pros, lz, barth1/2, and sev gene expression, suggesting its role in R7 photoreceptor differentiation. Taken together, these findings highlight the important role of dUCH in regulating genes associated with eye cell differentiation and its involvement in EGFR signalling in Drosophila melanogaster.

We are utilizing an adult penetrating traumatic brain injury (PTBI) model in Drosophila to investigate regenerative mechanisms after damage to the central brain. Here, we focus on cell proliferation as an early event in the regenerative process. To identify pathways that could trigger cell proliferation following PTBI, we utilized bulk RNA-Seq. We find that transcript levels for components of both Toll and Immune Deficiency (Imd) innate immunity pathways are rapidly and highly upregulated post-PTBI. We then tested mutants for the NF-κB transcription factors of the Toll and Imd pathways, Dorsal-related immunity factor (Dif) and Relish (Rel), respectively. We find that loss of either Dif or Rel results in loss of cell proliferation after injury and identify tissue-specific requirements for Dif and Rel. In addition, while the canonical downstream targets of Drosophila innate immune signalling, the antimicrobial peptides (AMPs), are upregulated following PTBI, their levels revert to near baseline within 24 hr. Taken together, these results indicate that the innate immunity pathways play an integral role in the regenerative response and that this response may not require the antimicrobial peptides. Innate immunity previously has been implicated as both a potentiator and an inhibitor of regenerative processes. Our work suggests that modulation of innate immunity may be essential to prevent adverse outcomes. Thus, this work is likely to inform future experiments to dissect regenerative mechanisms in higher organisms as well as in Drosophila.

The bipartite GAL4/UAS system is the most widely used method for targeted gene expression in Drosophila melanogaster and facilitates rapid in vivo genetic experimentation. Defining precise gene expression patterns for tissues and/or cell types under GAL4 control will continue to evolve to suit experimental needs. However, the precise spatial and temporal expression patterns for some commonly used muscle tissue promoters are still unclear. This missing information limits the precise timing of experiments during development. Here, we focus on three muscle-enriched GAL4 drivers (Mef2-GAL4, C57-GAL4 and G7-GAL4) to better inform selection of the most appropriate muscle promoter for experimental needs. Specifically, C57-GAL4 and G7-GAL4 turn on in the first or second instar larval stages, respectively, and can be used to bypass myogenesis for studies of muscle function after development.

The aim of the present study was to assess sleep timing in Drosophila melanogaster at different ages, within the setting of an enforced schedule of varying light-dark stimuli, simulating light exposure variations between four typical office working days and one free day spent outside by a human, for a total of 30 days. Locomotor activity recording started when male flies were 3 days old. Flies exhibited a bimodal activity pattern, with a morning and an evening peak, and clear anticipation of the lights on and lights off transitions. From experimental day 10 (i.e. 12-day-old flies) onwards, a decrease in activity counts/increase in sleep amount were observed. On free days, a rise in activity counts and a reduction in sleep amount during the lights on interval was observed and was also present, albeit less obvious, on the subsequent working day during the lights off interval. A progressive delay in sleep onset was observed in the first days of the experiment, peaking on day 4 (i.e. 6-day-old flies), after which sleep onset timing gradually advanced. A delay in sleep offset was also observed for the first 13 days of the experiment, after which sleep offset stabilized. In conclusion, 'adolescent' flies exhibited changes in sleep timing that were reminiscent of those of human adolescents.