Biology subjects

Cantera, R.

Publications and source records attributed to Cantera, R..

8 recordsLinked to original sources

bioRxiv2025

Disruption of hemocyte differentiation and distribution in Drosophila Ptr23c mutants

In Drosophila, hemocytes are essential for development and immunity, with their differentiation and spatial distribution under strict regulation. Here, we examine the effect of the Ptr23c null mutation in embryonic hemocyte development. Contrary to our initial hypothesis, Ptr does not regulate hemocyte number, as the mutation did not affect the total number of hemocytes, apoptosis, mitosis, or the balance between major subpopulations. However, Ptr23c mutants displayed disrupted distribution and premature hemocyte differentiation, marked by accelerated maturation at stage 12. Despite this early differentiation, Ptr23c embryos exhibited a 50% reduction in mature hemocytes by stage 16, as quantified by serpent-driven mCherry expression. Our findings establish Ptr as a regulator of hemocyte distribution and differentiation timing during normal embryogenesis, possibly through modulation of the serpent pathway.

developmental biology↗

bioRxiv2024

Clock genes period and timeless control synaptogenesis in Drosophila motor terminals

Some neurons undergo rhythmic morphological changes that persist in constant darkness and require the expression of clock genes. Flight motoneuron MN5, one of the best studied neurons of Drosophila melanogaster exhibits several examples of this type of circadian structural plasticity. During the morning, when the fly is active, synaptic boutons are larger than during the night when the fly is resting though more synaptic boutons and synapses are observed. Here, by comparing bouton numbers at different timepoints in normal flies and in flies carrying loss-of-function mutations in clock genes timeless (tim) or period (per), we investigate whether the rhythmic changes in numbers of boutons and synapses require the expression of these genes. Absence of tim expression abolished the rhythm in bouton number whereas absence of per expression appeared to increase the rhythms amplitude. This indicates that in normal flies TIM protein is necessary to drive the normal rhythm of bouton number and PER probably has a damping effect on it. In addition, it appears that tim and per expression normally act as inhibitor of synaptogenesis because their loss-of-function mutations caused over-proliferation of synapses. Unexpectedly, TIM and PER were expressed in different cells. TIM was found in the glial sheath wrapping the motoneurons axon and PER was predominantly found along the axon, suggesting that the control of the rhythmic change in bouton and synapse numbers requires interactions between different cell types.

neuroscience↗

bioRxiv2024

Atypical soluble guanylyl cyclases control brain size in Drosophila

Hypoxia-induced proliferation of neural stem cells has a crucial role in brain development. In the brain of Drosophila melanogaster, the optic lobe exhibits progressive hypoxia during larval development. Here, we investigate an alternative oxygen-sensing mechanism within this brain compartment, distinct from the canonical hypoxia signaling pathway mediated by HIF. Using genetic tools, immunostaining, and confocal microscopy, we demonstrate that the loss of the atypical soluble guanylyl cyclase (asGC) subunit Gyc88E, or the ectopic expression of Gyc89Db in neural stem cells leads to increased optic lobe volume. We propose the existence of a link between cGMP signaling and neurogenesis in the developing brain.

developmental biology↗

bioRxiv2024

Survival, Movement, and Lifespan: Decoding the Roles of Patched-Related (Ptr) in Drosophila melanogaster

Patched-related (Ptr) is a transmembrane protein implicated in developmental processes in Drosophila melanogaster, yet its precise role remains incompletely understood. Here, we use Ptr23c null mutants to investigate the functional significance of Ptr through the entire life cycle monitoring survival during embryonic, larval, pupal and adult development, and studying larval locomotion and muscle structure. We report that Ptr23c larvae displayed impaired hatching, indicative of defective embryonic development. Moreover, mutant larvae exhibited reduced mobility and lethargy, suggesting a potential involvement of Ptr in neuromuscular function. Morphological analysis of somatic muscles in mutant larvae revealed enlarged cell nuclei. Despite high pre-adult mortality, a subset of Ptr23c mutant adults display an unexpected extension in lifespan compared to controls, implicating Ptr in the regulation of longevity. Our findings provide critical insights into the multifaceted role of Ptr in Drosophila development, highlighting its contributions to post-embryonic survival, neuromuscular function, and lifespan regulation. This study underscores the significance of exploring broader genetic networks to unravel the complexities of developmental processes. Highlights- Loss of Ptr elicits impaired embryonic hatching, reduced mobility, and lethargy. - Ptr23c mutants display nuclear enlargement in somatic muscles. - Ptr23c individuals that survive to adulthood demonstrate extended longevity.

developmental biology↗

bioRxiv2022

Diversification of neuropil organization in specialized and broadly tuned olfactory glomerular circuits in Drosophila melanogaster

In the Drosophila olfactory system most odorants are encoded in the antennal lobe in a combinatory way, activating several glomerular circuits. However, odorants of particular ecological role for the fly are encoded through activation of a single specialized olfactory pathway. Comparative analyses of densely reconstructed connectomes of one broadly tuned glomerulus (DL5) and one narrowly tuned glomerulus (DA2) gained detailed insight into the variations of synaptic circuitries of glomeruli with different computational tasks. Our approach combined laser-branding of glomeruli of interest with volume based focused ion beam-scanning electron microscopy (FIB-SEM) to enable precise targeting and analysis of the two glomeruli. We discovered differences in their neuronal innervation, synaptic composition and specific circuit diagrams of their major cell types: olfactory sensory neurons (OSNs), uniglomerular projection neurons (uPNs) and multiglomerular neurons (MGNs). By comparing our data with a previously mapped narrowly tuned glomerulus (VA1v), we identified putative generic features of narrowly tuned glomerular circuits, including higher density of neuronal fibers and synapses, lower degree of OSN lateralization, stronger axo-axonic connections between OSNs, dendro-dendritic connections between many uPNs, and lower degree of presynaptic input on OSN axons. In addition, this work revealed that the dendrites of the single uPN in DL5 contain a substantial amount of autapses interconnecting distant regions of the dendritic tree. The comparative analysis of glomeruli allows to formulate synaptic motifs implemented in olfactory circuits with different computational demands.

neuroscience↗

bioRxiv2021

Gene function prediction in five model eukaryotes based on gene relative location through machine learning

MotiviationThe function of most genes is unknown. The best results in gene function prediction are obtained with machine learning-based methods that combine multiple data sources, typically sequence derived features, protein structure and interaction data. Even though there is ample evidence showing that a genes function is not independent of its location, the few available examples of gene function prediction based on gene location relay on sequence identity between genes of different organisms and are thus subjected to the limitations of the relationship between sequence and function. ResultsHere we predict thousands of gene functions in five eukaryotes (Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Mus musculus and Homo sapiens) using machine learning models trained with features derived from the location of genes in the genomes to which they belong. To the best of our knowledge this is the first work in which gene function prediction is successfully achieved in eukaryotic genomes using predictive features derived exclusively from the relative location of the genes. Contactfpazos@iibce.edu.uy Supplementary informationhttp://gfpml.bnd.edu.uy

bioinformatics↗

bioRxiv2020

Mosquito cellular immunity at single-cell resolution

Insect hemocytes are the functional equivalents of leukocytes and limit the capacity of mosquitoes to transmit human pathogens through phagocytosis, encapsulation, secretion of immune factors and immune priming (1, 2). Here we profile the transcriptomes of 8506 hemocytes of Anopheles gambiae and Aedes aegypti, two important mosquito vectors. Blood feeding, infection with malaria parasites and other immune challenges reveal a previously unknown functional diversity of hemocytes, with different types of granulocytes expressing distinct and evolutionarily conserved subsets of effector genes. A new cell type, which we term megacyte, is defined in Anopheles by a unique transmembrane protein marker (TM7318) and high expression of LPS-Induced TNF-alpha transcription factor 3 (LL3). Knock-down experiments indicate that LL3 mediates hemocyte differentiation during immune priming. We identify two main hemocyte lineages and find evidence of proliferating granulocyte populations. We validate our analysis with RNA in-situ hybridization and highlight the mobilization of sessile hemocytes into circulation upon infection. Our data (https://hemocytes.cellgeni.sanger.ac.uk/) provide the first atlas of medically relevant invertebrate immune cells at single cell resolution. It provides an important resource for invertebrate immunology by identifying cellular events that underpin mosquito immunity to malaria infection.

immunology↗

bioRxiv2019

Compartment and cell type-{-}specific hypoxia responses in the developing Drosophila brain

Environmental factors such as the availability of oxygen are instructive cues to regulate stem cell maintenance and differentiation. We used a genetically encoded biosensor to monitor the hypoxic state of neural cells in the larval brain of Drosophila. The biosensor reveals brain compartment and cell type specific levels of hypoxia. The values correlate with differential tracheolation that is observed throughout development between the central brain and the optic lobe. Neural stem cells in both compartments show the strongest hypoxia response while intermediate progenitors, neurons and glial cells reveal weaker responses. We demonstrate that the distance between a cell and the next closest tracheole is a good predictor of the hypoxic state for that cell. Our model concludes that oxygen availability is the major factor controlling the hypoxia response in the developing Drosophila brain but cell intrinsic and cell-type specific factors contribute to modulate the response in an unexpected manner.

developmental biology↗