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Genes May 2024Innate immune response is the first line of host defense against pathogenic microorganisms, and its excessive or insufficient activation is detrimental to the organism....
Innate immune response is the first line of host defense against pathogenic microorganisms, and its excessive or insufficient activation is detrimental to the organism. Many individual microRNAs (miRNAs) have emerged as crucial post-transcriptional regulators of immune homeostasis in . However, the synergistical regulation of miRNAs located within a cluster on the Imd-immune pathway remains obscured. In our study, a genetic screening with 52 transgenic UAS-miRNAs was performed to identify ten miRNAs or miRNA clusters, including the miR310~313 cluster, which may function on Imd-dependent immune responses. The miRNA RT-qPCR analysis showed that the expression of miR-310~313 cluster members exhibited an increase at 6-12 h post infection. Furthermore, the overexpression of the miR-310~313 cluster impaired the survival. And the overexpression of miR-310/311/312 reduced expression, an indication of Imd pathway induced by Gram-negative bacteria. Conversely, the knockdown of miR-310/311/312 led to increases in expression. The Luciferase reporter expression assays and RT-qPCR analysis confirmed that miR-310~313 cluster members directly co-targeted and inhibited transcription. These findings reveal that the members of the miR-310~313 cluster synergistically inhibit Imd-dependent immune responses by co-targeting the Imd gene in .
Topics: Animals; MicroRNAs; Drosophila Proteins; Drosophila melanogaster; Immunity, Innate; Multigene Family; Gram-Negative Bacterial Infections; Signal Transduction; Gene Expression Regulation; Genetic Testing; Escherichia coli
PubMed: 38790230
DOI: 10.3390/genes15050601 -
Genes Apr 2024Hairless (H) encodes the major antagonist in the Notch signaling pathway, which governs cellular differentiation of various tissues in . By binding to the Notch signal...
Hairless (H) encodes the major antagonist in the Notch signaling pathway, which governs cellular differentiation of various tissues in . By binding to the Notch signal transducer Suppressor of Hairless (Su(H)), H assembles repressor complexes onto Notch target genes. Using genome engineering, three new alleles, , and were generated and a phenotypic series was established by several parameters, reflecting the residual H-Su(H) binding capacity. Occasionally, homozygous flies develop to adulthood. They were compared with the likewise semi-viable allele affecting H-Su(H) nuclear entry. The homozygotes were short-lived, sterile and flightless, yet showed largely normal expression of several mitochondrial genes. Typical for mutants, both and homozygous alleles displayed strong defects in wing venation and mechano-sensory bristle development. Strikingly, however, displayed only a loss of bristles, whereas bristle organs of flies showed a complete shaft-to-socket transformation. Apparently, the impact of is restricted to lateral inhibition, whereas that of also affects the respective cell type specification. Notably, reduction in gene dosage only suppressed the bristle phenotype, but amplified that of . We interpret these differences as to the role of H regarding Su(H) stability and availability.
Topics: Animals; Drosophila Proteins; Alleles; Drosophila melanogaster; Wings, Animal; Transcription Factors; Gene Expression Regulation, Developmental; Repressor Proteins; Receptors, Notch; Signal Transduction
PubMed: 38790181
DOI: 10.3390/genes15050552 -
Biomolecules Apr 2024Suppressor of deltex () is a member of the NEDD4 family of the HECT domain E3 ubiquitin ligases. acts as a regulator of Notch endocytic trafficking, promoting Notch...
Suppressor of deltex () is a member of the NEDD4 family of the HECT domain E3 ubiquitin ligases. acts as a regulator of Notch endocytic trafficking, promoting Notch lysosomal degradation and the down-regulation of both ligand-dependent and ligand-independent signalling, the latter involving trafficking through the endocytic pathway and activation of the endo/lysosomal membrane. Mutations of result in developmental phenotypes in the wing that reflect increased Notch signalling, leading to gaps in the specification of the wing veins, and functions to provide the developmental robustness of Notch activity to environmental temperature shifts. The full developmental functions of are unclear; however, this is due to a lack of a clearly defined null allele. Here we report the first defined null mutation of , generated by P-element excision, which removes the complete open reading frame. We show that the mutation is recessive-viable, with the Notch gain of function phenotypes affecting wing vein and leg development. We further uncover new roles for in oogenesis, where it regulates interfollicular stalk formation, egg chamber separation and germline cyst enwrapment by the follicle stem cells. Interestingly, while the null allele exhibited a gain in Notch activity during oogenesis, the previously described allele, which carries a seven amino acid in-frame deletion, displayed a Notch loss of function phenotypes and an increase in follicle stem cell turnover. This is despite both alleles displaying similar Notch gain of function in wing development. We attribute this unexpected context-dependent outcome of being due to the partial retention of function by the intact C2 and WW domain regions of the protein. Our results extend our understanding of the developmental role of in the tissue renewal and homeostasis of the ovary and illustrate the importance of examining an allelic series of mutations to fully understand developmental functions.
Topics: Animals; Oogenesis; Drosophila melanogaster; Drosophila Proteins; Receptors, Notch; Alleles; Female; Wings, Animal; Mutation; Signal Transduction; Phenotype; Membrane Proteins
PubMed: 38785929
DOI: 10.3390/biom14050522 -
Biology Apr 2024Microplastics and nanoplastics are abundant in the environment. Further research is necessary to examine the consequences of microplastic contamination on living...
Microplastics and nanoplastics are abundant in the environment. Further research is necessary to examine the consequences of microplastic contamination on living species, given its widespread presence. In our research, we determined the toxic effects of PET microplastics on at the cellular and genetic levels. Our study revealed severe cytotoxicity in the midgut of larvae and the induction of oxidative stress after 24 and 48 h of treatment, as indicated by the total protein, , , and MDA contents. For the first time, cell damage in the reproductive parts of the ovaries of female flies, as well as in the accessory glands and testes of male flies, has been observed. Furthermore, a decline in reproductive health was noted, resulting in decreased fertility among the flies. By analyzing stress-related genes such as 83, 70, 60, and 26, we detected elevated expression of and . Our study identified as a specific biomarker for detecting early redox changes in cells caused by PET microplastics in all the treated groups, helping to elucidate the primary defense mechanism against PET microplastic toxicity. This study offers foundational insights into the emerging environmental threats posed by microplastics, revealing discernible alterations at the genetic level.
PubMed: 38785774
DOI: 10.3390/biology13050293 -
Current Research in Structural Biology 2024Extradenticle (EXD) is a partner protein of the HOX transcription factors and plays an important role in the development of Drosophila. It confers increased affinity and...
Extradenticle (EXD) is a partner protein of the HOX transcription factors and plays an important role in the development of Drosophila. It confers increased affinity and specificity of DNA-binding to the HOX proteins. However, the DNA-binding homeodomain of EXD has a significantly weaker affinity to DNA compared to the HOX homeodomains. Here, we show that a glycine residue (G290) in the middle of the EXD DNA-binding helix primarily results in this weaker binding. Glycine destabilizes helices. To probe its role in the stability and function of the protein, G290 was mutated to alanine. The intrinsic stability of the DNA-binding helix increased in the G290A mutant as observed by NMR studies and molecular dynamics (MD) simulation. Also, NMR dynamics and MD simulation show that dynamic motions present in the wild-type protein are quenched in the mutant. This in turn resulted in increased stability of the entire homeodomain (ΔΔG of -2.6 kcal/mol). Increased protein stability resulted in three-fold better DNA-binding affinity of the mutant as compared to the wild-type protein. Molecular mechanics with generalized Born and surface area solvation (MMGBSA) analysis of our MD simulation on DNA-bound models of both wild-type and mutant proteins shows that the contribution to binding is enhanced for most of the interface residues in the mutant compared to the wild-type. Interestingly, the flexible N-terminal arm makes more stable contact with the DNA minor groove in the mutant. We found that the two interaction sites i.e. the DNA-binding helix and the unstructured N-terminal arm influence each other via the bound DNA. These results provide an interesting conundrum: alanine at position 290 enhances both the stability and the DNA-binding affinity of the protein, however, evolution prefers glycine at this position. We have provided several plausible explanations for this apparent conundrum. The function of the EXD as a HOX co-factor requires its ability to discriminate similar DNA sequences, which is most likely comprom.
PubMed: 38784963
DOI: 10.1016/j.crstbi.2024.100150 -
Nature Communications May 2024Pancreatic β cells secrete insulin in response to glucose elevation to maintain glucose homeostasis. A complex network of inter-organ communication operates to modulate...
Pancreatic β cells secrete insulin in response to glucose elevation to maintain glucose homeostasis. A complex network of inter-organ communication operates to modulate insulin secretion and regulate glucose levels after a meal. Lipids obtained from diet or generated intracellularly are known to amplify glucose-stimulated insulin secretion, however, the underlying mechanisms are not completely understood. Here, we show that a Drosophila secretory lipase, Vaha (CG8093), is synthesized in the midgut and moves to the brain where it concentrates in the insulin-producing cells in a process requiring Lipid Transfer Particle, a lipoprotein originating in the fat body. In response to dietary fat, Vaha stimulates insulin-like peptide release (ILP), and Vaha deficiency results in reduced circulatory ILP and diabetic features including hyperglycemia and hyperlipidemia. Our findings suggest Vaha functions as a diacylglycerol lipase physiologically, by being a molecular link between dietary fat and lipid amplified insulin secretion in a gut-brain axis.
Topics: Animals; Drosophila Proteins; Brain; Insulin Secretion; Insulin; Drosophila melanogaster; Insulin-Secreting Cells; Brain-Gut Axis; Lipase; Dietary Fats; Glucose; Fat Body; Lipoprotein Lipase; Male
PubMed: 38782979
DOI: 10.1038/s41467-024-48851-8 -
Cellular and Molecular Life Sciences :... May 2024Insect host defense comprises two complementary dimensions, microbial killing-mediated resistance and microbial toxin neutralization-mediated resilience, both jointly...
Insect host defense comprises two complementary dimensions, microbial killing-mediated resistance and microbial toxin neutralization-mediated resilience, both jointly providing protection against pathogen infections. Insect defensins are a class of effectors of innate immunity primarily responsible for resistance to Gram-positive bacteria. Here, we report a newly originated gene from an ancestral defensin via genetic deletion following gene duplication in Drosophila virilis, which confers an enhanced resilience to Gram-positive bacterial infection. This gene encodes an 18-mer arginine-rich peptide (termed DvirARP) with differences from its parent gene in its pattern of expression, structure and function. DvirARP specifically expresses in D. virilis female adults with a constitutive manner. It adopts a novel fold with a 3 helix and a two CXC motif-containing loop stabilized by two disulfide bridges. DvirARP exhibits no activity on the majority of microorganisms tested and only a weak activity against two Gram-positive bacteria. DvirARP knockout flies are viable and have no obvious defect in reproductivity but they are more susceptible to the DvirARP-resistant Staphylococcus aureus infection than the wild type files, which can be attributable to its ability in neutralization of the S. aureus secreted toxins. Phylogenetic distribution analysis reveals that DvirARP is restrictedly present in the Drosophila subgenus, but independent deletion variations also occur in defensins from the Sophophora subgenus, in support of the evolvability of this class of immune effectors. Our work illustrates for the first time how a duplicate resistance-mediated gene evolves an ability to increase the resilience of a subset of Drosophila species against bacterial infection.
Topics: Drosophila; Defensins; Drosophila Proteins; Animals; Gene Deletion; Gene Duplication; Female; Protein Folding; Amino Acid Motifs; Bacterial Toxins; Staphylococcus aureus
PubMed: 38780625
DOI: 10.1007/s00018-024-05273-5 -
F1000Research 2023How the precise spatial regulation of genes is correlated with spatial variation in chromatin accessibilities is not yet clear. Previous studies that analysed chromatin...
How the precise spatial regulation of genes is correlated with spatial variation in chromatin accessibilities is not yet clear. Previous studies that analysed chromatin from homogenates of whole-body parts of insects found little variation in chromatin accessibility across those parts, but single-cell studies of brains showed extensive spatial variation in chromatin accessibility across that organ. In this work we studied the chromatin accessibility of butterfly wing tissue fated to differentiate distinct colors and patterns in pupal wings of We dissected small eyespot and adjacent control tissues from 3h pupae and performed ATAC-Seq to identify the chromatin accessibility differences between different sections of the wings. We observed that three dissected wing regions showed unique chromatin accessibilities. Open chromatin regions specific to eyespot color patterns were highly enriched for binding motifs recognized by Suppressor of Hairless (Su(H)), Krüppel (Kr), Buttonhead (Btd) and Nubbin (Nub) transcription factors. Genes in the vicinity of the eyespot-specific open chromatin regions included those involved in wound healing and SMAD signal transduction pathways, previously proposed to be involved in eyespot development. We conclude that eyespot and non-eyespot tissue samples taken from the same wing have distinct patterns of chromatin accessibility, possibly driven by the eyespot-restricted expression of potential pioneer factors, such as Kr.
Topics: Animals; Butterflies; Chromatin; Wings, Animal; Pigmentation; Insect Proteins; Transcription Factors
PubMed: 38778811
DOI: 10.12688/f1000research.133789.1 -
European Journal of Cell Biology Jun 2024The Microphthalmia-associated Transcription Factor (MITF) governs numerous cellular and developmental processes. In mice, it promotes specification and differentiation...
The Microphthalmia-associated Transcription Factor (MITF) governs numerous cellular and developmental processes. In mice, it promotes specification and differentiation of the retinal pigmented epithelium (RPE), and in humans, some mutations in MITF induce congenital eye malformations. Herein, we explore the function and regulation of Mitf in Drosophila eye development and uncover two roles. We find that knockdown of Mitf results in retinal displacement (RDis), a phenotype associated with abnormal eye formation. Mitf functions in the peripodial epithelium (PE), a retinal support tissue akin to the RPE, to suppress RDis, via the Hippo pathway effector Yorkie (Yki). Yki physically interacts with Mitf and can modify its transcriptional activity in vitro. Severe loss of Mitf, instead, results in the de-repression of retinogenesis in the PE, precluding its development. This activity of Mitf requires the protein phosphatase 2 A holoenzyme STRIPAK-PP2A, but not Yki; Mitf transcriptional activity is potentiated by STRIPAK-PP2A in vitro and in vivo. Knockdown of STRIPAK-PP2A results in cytoplasmic retention of Mitf in vivo and in its decreased stability in vitro, highlighting two potential mechanisms for the control of Mitf function by STRIPAK-PP2A. Thus, Mitf functions in a context-dependent manner as a key determinant of form and fate in the Drosophila eye progenitor epithelium.
Topics: Animals; Drosophila Proteins; Microphthalmia-Associated Transcription Factor; YAP-Signaling Proteins; Trans-Activators; Nuclear Proteins; Eye; Protein Phosphatase 2; Drosophila melanogaster; Epithelium; Cell Differentiation; Homeodomain Proteins
PubMed: 38776620
DOI: 10.1016/j.ejcb.2024.151421 -
PloS One 2024The detrimental effects of ultraviolet C (UVC) radiation on living organisms, with a specific focus on the fruit fly Drosophila melanogaster, were examined. This study...
The detrimental effects of ultraviolet C (UVC) radiation on living organisms, with a specific focus on the fruit fly Drosophila melanogaster, were examined. This study investigated the impact of heightened UVC radiation exposure on D. melanogaster by assessing mortality and fertility rates, studying phenotypic mutations, and investigating the associated molecular mechanisms. The findings of this study revealed that UVC radiation increases mortality rates and decreases fertility rates in D. melanogaster. Additionally, phenotypic wing mutations were observed in the exposed flies. Furthermore, the study demonstrated that UVC radiation downregulates the expression of antioxidant genes, including superoxide dismutase (SOD), manganese-dependent superoxide dismutase (Mn-SOD), zinc-dependent superoxide dismutase (Cu-Zn-SOD), and the G protein-coupled receptor methuselah (MTH) gene. These results suggest that UVC radiation exerts a destructive effect on D. melanogaster by inducing oxidative stress, which is marked by the overexpression of harmful oxidative processes and a simultaneous reduction in antioxidant gene expression. In conclusion, this study underscores the critical importance of comprehending the deleterious effects of UVC radiation, not only to safeguard human health on Earth, but also to address the potential risks associated with space missions, such as the ongoing Emirate astronaut program.
Topics: Animals; Drosophila melanogaster; Ultraviolet Rays; Fertility; Mutation; Drosophila Proteins; Oxidative Stress; Male; Female; Superoxide Dismutase; Antioxidants; Gene Expression Regulation
PubMed: 38776353
DOI: 10.1371/journal.pone.0303115