Biology subjects

Paton, C.

Publications and source records attributed to Paton, C..

4 recordsLinked to original sources

bioRxiv2024

Polycomb-mediated transgenerational epigenetic inheritance of Drosophila eye colour is independent of small RNAs

Transgenerational epigenetic inheritance (TEI) describes the process where distinct epigenetic states may be transmitted between generations, resulting in stable gene expression and phenotypic differences between individuals that persist independently of DNA sequence variation. Chromatin modifications have been demonstrated as important in TEI, however, the extent to which they require other signals to establish and maintain epigenetic states is still unclear. Here we investigate whether small non-coding RNAs contribute to different epigenetic states of the Fab2L transgene in Drosophila triggered by transient chromatin contacts, which requires Polycomb complex activity to deposit the H3K27me3 modification for long-term TEI. Using mutants deficient in known small non-coding RNAs, high throughput sequencing, investigation of chromatin conformation and gene expression analysis we demonstrate that small non-coding RNAs do not contribute directly to initiation or maintenance of silencing. However, we uncover an indirect role for microRNA expression in transgene silencing through effects on Polycomb complex expression. Additionally, we show that a commonly used marker gene, Stubble (Sb), affects Polycomb complex expression, which may be important in interpreting experiments assaying Polycomb function in Drosophila development. By ruling out a plausible candidate for TEI at the Fab2L transgene our work highlights the variability in different modes of TEI across species.

biochemistry↗

bioRxiv2022

The Tre1/S1pr1 phospholipid-binding G protein-coupled receptor signaling pathway is required for astrocyte morphogenesis

Astrocytes play crucial roles in regulating neural circuit function by forming a dense network of synapse-associated membrane specializations, but signaling pathways regulating astrocyte morphogenesis remain poorly defined. Here we show the Drosophila lipid-binding G protein-coupled receptor (GPCR) Tre1, likely acting through Rac1, is required for astrocytes to elaborate their complex morphology in vivo. The lipid phosphate phosphatases Wunen/Wunen2, which process phospholipid ligands, also regulate astrocyte morphology, and, via Tre1, mediate astrocyte-astrocyte competition for growth promoting lipids. Loss of s1pr1, the functional analog of Tre1 in zebrafish disrupts astrocyte process elaboration. Live-imaging and pharmacology demonstrate that S1pr1 balances proper astrocyte process extension/retraction dynamics during morphogenesis, and that S1pr1 signaling is required throughout astrocyte development. Tre1 and S1pr1 are thus potent evolutionarily conserved regulators of astrocyte growth and elaboration of morphological complexity. O_LIThe GPCR Tre1 and LPPs Wun/Wun2 promote astrocyte process outgrowth in Drosophila C_LIO_LIAstrocytes compete for a growth{-}promoting phospholipid in the CNS C_LIO_LIWun/Wun2 act locally to regulate process outgrowth through Tre1 C_LIO_LIVertebrate S1pr1 regulates astrocyte growth early, through modulation of process dynamics C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=162 SRC="FIGDIR/small/508188v2_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1e86db5org.highwire.dtl.DTLVardef@7abd6borg.highwire.dtl.DTLVardef@29f163org.highwire.dtl.DTLVardef@1a6c4b9_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2020

Mark-release-recapture of male Aedes aegypti (Diptera: Culicidae): use of rhodamine B to estimate movement, mating and population parameters in preparation for an incompatible male program.

Rapid advances in biological and digital technologies are revolutionizing the population control of invasive disease vectors such as Aedes aegypti. Methods such as the sterile and incompatible insect techniques (SIT/IIT) rely on modified males to seek out and successfully mate with females, and in doing so outcompete the wild male population for mates. Currently, these interventions infer the success of mating interactions between male and female insects through area-wide population surveillance and observations of mating competitiveness are rare. Furthermore, little is known about male Ae. aegypti behaviours and biology in field settings. In preparation for a large, community scale IIT program, we undertook a series of mark-release-recapture experiments using rhodamine B to mark male Ae. aegypti sperm and measure mating interactions with females. We also developed the Spatial and Temporally Evolving Isotropic Kernel (STEIK) framework to assist researchers to estimate the movement of individuals through space and time. Results showed that ~40% of daily females captured were unmated, suggesting interventions will need to release males regularly to be effective at suppressing Ae. aegypti populations. Males moved rapidly through the landscape, particularly when released during the night. Although males moved further than what is typically observed in females of the species, survival was considerably lower. These unique insights will lead to a greater understanding of mating interactions in wild insect populations and lay the foundation for robust suppression strategies in the future. Author SummaryModern scientific techniques for controlling populations of the dengue vector, Aedes aegypti, utilize the mating biology of adult male mosquitoes to achieve suppression through a sterilization process. As the study of Ae. aegypti control has typically focused on adult female mosquitoes, knowledge on male movement, survival and mating interactions in the field is lacking. Here we undertook several mark-release-recapture experiments on adult male Ae. aegypti in Innisfail, Australia, and measured important biological parameters. For the first time in large field experiments, we employed rhodamine B as a marker that when fed to adult males, identified both marked males and the wild females they mated with. We observed males moving further through the landscape, but surviving for a shorter period, than previous measurements undertaken on females in a field setting. A high proportion (~40%) of unmated females suggests individuals are constantly available for mating. As such, sterile male strategies may need to release at regular intervals to achieve effective population suppression. The unique insights provided by this study will assist in designing future sterile male field interventions.

ecology↗

bioRxiv2020

Modelling the Wolbachia Incompatible Insect Technique: strategies for effective mosquito population elimination

The Wolbachia Incompatible Insect Technique (IIT) shows promise as a method for eliminating invasive mosquitoes such as Aedes aegypti (Linnaeus)(Diptera: Culicidae) and reducing the incidence of vector-borne diseases such as dengue, chikungunya and Zika. Successful implementation of this biological control strategy relies on high-fidelity separation of male from female insects in mass production systems for inundative release into landscapes. Processes for sex-separating mosquitoes are typically error prone, laborious and IIT programs run the risk of releasing Wolbachia infected females and replacing wild mosquito populations. We introduce a simple Markov Population Process (MPP) model for studying mosquito populations subjected to a Wolbachia-IIT program which exhibit an unstable equilibrium threshold. The model is used to study, in silico, scenarios that are likely to yield a successful elimination result. Our results suggest that elimination is best achieved by releasing males at rates that adapt to the ever-decreasing wild population, thus reducing the risk of releasing Wolbachia-infected females while reducing costs. While very high-fidelity sex-separation is required to avoid establishment, release programs tend to be robust to the release of a small number of Wolbachia-infected females. These findings will inform and enhance the next generation of Wolbachia-IIT control strategies that are already showing great promise in field trials.

zoology↗