Biology subjects

Rosato, E.

Publications and source records attributed to Rosato, E..

12 recordsLinked to original sources

bioRxiv2025

Evolutionarily conserved transcriptional regulators control monoaminergic neuron development

To what extent conserved developmental programs specify homologous cell types is a central question in biology. Here, we address this by focusing on reconstructing monoaminergic neuron development in Drosophila melanogaster embryo using time- resolved single-cell genomics, spatial transcript mapping with hybridisation chain reaction, and targeted metabolomics. We uncover a regulatory landscape in which specific transcription factors are activated before biosynthetic enzymes, establishing a prospective temporal architecture for monoaminergic fate specification. Comparative analyses of developmental single-cell atlases from zebrafish and sea urchin indicate that components of this machinery are conserved across [~]550 million years of bilaterian evolution with orthologous transcription factors showing similar temporal dynamics. Together, these findings point to a putatively conserved regulatory core that interfaces with other context-dependent transcription factors; this interplay accommodates monoaminergic multifunction and subtype diversity across distinct neuroanatomies.

evolutionary biology↗

bioRxiv2025

Monoaminergic neurons share transcriptional identity across Bilaterian animals

The evolutionary conservation of cell types over deep time has long been theorised but remains difficult to demonstrate. Monoaminergic neurons, which produce molecules such as serotonin and dopamine, are central to animal behaviour and cognition, yet their evolutionary origins remain unresolved. Here, we analysed single-cell transcriptomes from 16 metazoan species spanning eight phyla. Using a novel integration method, Orthogroup Recoding, together with experimental validation, we show that monoaminergic neurons form consistent transcriptional clusters across Bilateria. These clusters share a regulatory signature involving conserved transcription factors, including homologues of Fev, Lmx1b, Fer2, Insm, and Isl, suggesting a common regulatory program. This signature extends beyond the brain including other monoaminergic cells, such as the gut enterochromaffin cells and larval sensory neurons. By contrast, non-bilaterian lineages lack the coordinated expression of the transcription factors and the biosynthetic machinery that regulate monoamine production. Our observations support the existence of a shared set of TFs that define monoaminergic identity across in bilaterians.

bioinformatics↗

bioRxiv2025

How the Drosophila Cryptochrome C-terminus mediates magnetosensitivity

The Earths magnetic field plays an important role in the seasonal migrations of many species of animals. A Cryptochrome (CRY)-based radical pair mechanism (RPM) has been suggested to underlie the mechanistic basis of animal magnetosensitivity and navigation. The quantum spin state of a radical pair involving flavin adenine dinucleotide (FAD) bound to CRY in the canonical pocket is sensitive to external magnetic fields that can alter the signalling concentration of activated CRY1-5. However, several experimental observations challenge this model including the finding that the C-terminal fragment of Drosophila CRY (DmCRY), which lacks any canonical FAD binding pocket, and human CRY2, which lacks affinity for FAD, are sufficient to support magnetosensitivity6-9. Here, we use all-atom molecular dynamic (MD) simulations, alongside in vitro and in vivo analyses to reveal that the C-terminus of Drosophila CRY (DmCRY-CT) binds FAD. FAD binding is required for transduction of a magnetic signal within cells, and, in vitro, initiates formation of high molecular weight DmCRY-CT oligomers, including large insoluble aggregates reminiscent of CRY photobodies observed in plants10-14. These results provide a plausible mechanistic basis for several experimental observations that have reported non-canonical magnetosensitivity in animals.

biochemistry↗

bioRxiv2024

Ultrastructural correlates of circadian structural plasticity

In Drosophila, about 250 clock neurons in the brain form a network that orchestrates circadian rhythmicity. Among them, eight small Lateral ventral Neurons (s-LNvs) play a critical role, synchronizing the circadian ensemble via the neuropeptide Pigment-Dispersing Factor (PDF). Moreover, their neurites show daily variations in morphology, PDF levels, synaptic markers and connectivity. This process, called circadian structural plasticity, is ill-defined at the subcellular level. Here, we present 3D volumes of the s-LNv terminals generated by Serial Block-face Scanning Electron Microscopy (SBEM) at three key time points, two hours before lights-ON, two hours after lights-ON, and two hours after lights-OFF. We report a reduction in the number of neuronal varicosities at night, which reflects (and probably regulates) the cycling of the components we found therein. Indeed, in the morning we observed more presynaptic sites and increased accumulation and release of dense core vesicles. These rhythms were paralleled by periodic changes in mitochondrial structure that suggest daily modulation of their activity. We propose that circadian plasticity of the functionally relevant structures within presynaptic varicosities cyclically modulates the influence of the s-LNvs on the clock network.

neuroscience↗

bioRxiv2024

Neuronal progenitors suffer genotoxic stress in the Drosophila clock mutant per0.

The physiological role and the molecular architecture of the circadian clock in fully developed organisms are well established. Yet, we have a limited understanding about the function of the clock during ontogenesis. We have used a null mutant (per0) of the clock gene period (per) in Drosophila melanogaster to ask whether PER may play a role during normal brain development. In 3rd instar larvae, we have observed that absence of functional per results in increased genotoxic stress compared to wild type controls. We have detected increased double strand DNA breaks in the central nervous system and chromosome aberrations in dividing neuronal precursor cells. We have demonstrated that reactive oxygen species (ROS) are causal to the genotoxic effect and that expression of PER in glia is necessary and sufficient to suppress such a phenotype. Finally, preliminary evidence indicates that absence of PER may result in less condensed chromatin, which may contribute to DNA damage.

genetics↗

bioRxiv2024

Hematophagy generates a convergent genomic signature in mosquitoes and sandflies

Blood-feeding (hematophagy) is widespread across Diptera (true flies), yet the underlying molecular mechanisms remain poorly understood. Using phylogenomics, we show that four gene families associated with neuro-modulation, immune responses, embryonic development, and iron metabolism have undergone independent expansions within mosquitoes and sandflies. Our findings illuminate the underlying genetic basis for blood-feeding adaptations in these important disease vectors.

evolutionary biology↗

bioRxiv2024

Molecular correlates of swarming behaviour in Aedes aegypti males.

Mosquitoes are the deadliest vectors of disease. They impose a huge health burden on human populations spreading parasites as disparate as protozoans (malaria), viruses (yellow fever and more), and nematodes (filariasis), which cause life-threatening conditions. In recent years, mating has been proposed as a putative target for population control. Mosquitoes mate mid-air in swarms initiated by males and triggered by a combination of internal and external stimuli. As the number of females in a swarm is limited, there is intense competition among males. Indeed, males retune their physiology for this demanding behaviour but the underlying genetic changes are largely unknown. Interestingly, recent evidence indicates that the upregulation of circadian clock genes may be involved in the swarming of malaria mosquitoes of the genus Anopheles. Here, we use whole-head RNA-seq to identify gene expression changes in Aedes aegypti males who are engaged in swarming in a laboratory setting. Our results suggest that swarming males tend to lower some housekeeping functions while increasing the remodelling of the cytoskeleton and neuronal connectivity; the transcription of circadian clock genes is unaffected.

genetics↗

bioRxiv2022

Neuromodulation by Monoamines is a Bilaterian Innovation

Monoamines like serotonin, dopamine, and adrenaline/noradrenaline (epinephrine/ norepinephrine) act as neuromodulators that tune the response of the nervous system to the environment with predictable advantages for fitness. For instance, monoamines influence action selection depending on the internal state of the organism, contribute to higher cognitive functions like learning and memory formation and modulate fundamental homeostatic needs such as sleep or feeding. Despite their significance and the extensive research in model organisms, the evolutionary origin of the monoaminergic system is uncertain. Here using a phylogenomic approach we study the evolution of the majority of genes involved in the production, modulation, and detection of monoamines. Our analyses suggest that most of the genes of the monoaminergic system originated in the common ancestor of bilaterians. These findings suggest that the monoaminergic synaptic pathway is a bilaterian innovation. We hypothesise that monoaminergic neuromodulation contributed to the diversification and complexification of behaviour and forms found in Bilateria.

evolutionary biology↗

bioRxiv2021

Essential elements of radical pair magnetosensitivity in Drosophila

Many animals use the Earths magnetic field (geoMF) for navigation1. The favored mechanism for magnetosensitivity involves a blue-light (BL) activated electron transfer reaction between flavin adenine dinucleotide (FAD) and a chain of tryptophan (Trp) residues within the photoreceptor protein, CRYPTOCHROME (CRY). The spin-state of the resultant radical pair (RP), and hence the concentration of CRY in its active state, is influenced by the geoMF2. The canonical CRY-centric radical pair mechanism (RPM) does not, however, explain many physiological and behavioural observations2-8. Here, using electrophysiology and behavioural analyses, we assay magnetic field (MF) responses at single neuron and organismal level. We show that the 52 C-terminal (CT) amino acids of CRY, which are missing the canonical FAD binding domain and Trp chain, are sufficient to facilitate magnetoreception. We also show that increasing intracellular FAD potentiates both BL-induced and MF-dependent effects on the activity mediated by the CT. Additionally, high levels of FAD alone are sufficient to cause BL neuronal sensitivity and, remarkably, potentiation of this response in the co-presence of a MF. These unexpected results reveal the essential components of a primary magnetoreceptor in flies, providing strong evidence that non-canonical (i.e., non-CRY-dependent) RPs can elicit MF responses in cells.

physiology↗

bioRxiv2020

The diverging evolutionary history of opsin genes in Diptera

Opsin receptors mediate the visual process in animals and their evolutionary history can provide precious hints on the ecological factors that underpin their diversification. Here we mined the genomes of more than 60 Dipteran species and reconstructed the evolution of their opsin genes in a phylogenetic framework. Our phylogenies indicate that dipterans possess an ancestral set of five core opsins which have undergone several lineage-specific events including an independent expansion of low wavelength opsins in flies and mosquitoes and numerous family specific duplications and losses. Molecular evolutionary studies indicate that gene turnover rate, overall mutation rate, and site-specific selective pressure are higher in Anopheles than in Drosophila; we found signs of positive selection in both lineages, including events possibly associated with their peculiar behaviour. Our findings indicate an extremely variable pattern of opsin evolution in dipterans, showcasing how two similarly aged radiations - Anopheles and Drosophila - can be characterized by contrasting dynamics in the evolution of this gene family.Competing Interest StatementThe authors have declared no competing interest.View Full Text

evolutionary biology↗

bioRxiv2019

In silico identification of a molecular circadian system with novel features in the crustacean model organism Parhyale hawaiensis

The amphipod Parhyale hawaiensis is a model organism of growing importance in the fields of evolutionary development and regeneration. A small, hardy marine crustacean that breeds year-round with a short generation time, it has simple lab culture requirements and an extensive molecular toolkit including the ability to generate targeted genetic mutant lines. Here we identify canonical core and regulatory clock genes using genomic and transcriptomic resources as a first step in establishing this species as a model in the field of chronobiology. The molecular clock of P. hawaiensis lacks orthologs of the canonical circadian genes cryptochrome 1 and timeless, in common with the mammalian system but in contrast to many arthropods including Drosophila melanogaster. Furthermore the predicted CLOCK peptide is atypical and CRY2 shows an extended 5 region of unknown function. These results appear to be shared by two other amphipod species.

molecular biology↗

bioRxiv2019

The effects of the neonicotinoid imidacloprid on gene expression and DNA methylation in the buff-tailed bumblebee Bombus terrestris

Neonicotinoids are effective insecticides used on many important arable and horticultural crops. They are nicotinic acetylcholine receptor agonists which disrupt the function of insect neurons and cause paralysis and death. In addition to direct mortality, there are numerous sublethal effects of low doses of neonicotinoids on bees. We hypothesize that some of these large array of effects could be a consequence of epigenetic changes in bees induced by neonicotinoids. We compared whole methylome (BS-seq) and RNA-seq libraries of the brains of buff tailed bumblebee Bombus terrestris workers exposed to field realistic doses of the neonicotinoid imidacloprid to libraries from control workers. We found numerous genes which show differential expression between neonicotinoid treated bees and control bees, but no differentially methylated cytosines in any context. We found CpG methylation to be focused mainly in exons and associated with highly expressed genes. We discuss the implications of our results for future legislation.

ecology↗