Biology subjects

Davies, E. L.

Publications and source records attributed to Davies, E. L..

4 recordsLinked to original sources

bioRxiv2025

Protocol combining RNA interference and regeneration assays in planarian embryos

Planarian flatworms gradually acquire whole-body regeneration abilities during late embryonic and juvenile development. Here we show how to perturb gene function with RNA interference (RNAi) in S. polychroa embryos at developmental stages capable of wound healing following amputation. We describe embryo staging, embryo amputation and double-stranded RNA soaking, phenotype analysis, and techniques for qualitative and quantitative assessment of RNAi knock-down efficacy. This protocol is adaptable for use with embryonic stages amenable to ex vivo culturing and with other embryo-producing flatworm species. For complete details on the use and execution of this protocol, please refer to 1. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/666018v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@d4bf29org.highwire.dtl.DTLVardef@1524f6forg.highwire.dtl.DTLVardef@dd40b0org.highwire.dtl.DTLVardef@1c1f6bf_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2025

Alternative splicing broadens antiviral diversity at the human OAS2 locus

Interferons (IFN) are cytokines that regulate the expression of hundreds of genes during viral infections to generate a broadly antiviral environment in the stimulated cell. Antiviral breadth is provided by the concurrent expression of many individual IFN-stimulated genes (ISG), each encoding a protein with often exquisite antiviral specificity. Here, we show that mechanistic plasticity at a single genetic locus is a novel mechanism to diversify the antiviral profile of human cells. Through alternative splicing, the OAS2 gene encodes two antiviral molecules with distinct target specificities. The shorter OAS2 p69 isoform blocks the replication of seasonal human coronavirus OC43 (HCoV-OC43), while the longer p71 isoform restricts the replication of picornavirus Cardiovirus A (EMCV). The restriction profile is determined by the variable length OAS2 C-terminal tail. Remarkably, the antiviral mechanisms underlying these distinct antiviral profiles are either RNase L dependent or independent, suggesting that splicing divides classic restriction versus virus sensing systems across two distinct OAS2 polypeptides. Together, our data reveal that the human OAS2 locus uses alternative splicing and mechanistic plasticity to diversify antiviral profiles.

microbiology↗

bioRxiv2024

Axis reset is rate limiting for onset of whole-body regenerative abilities during planarian development

Few studies have investigated whether or how regenerative abilities vary across developmental stages of animal life cycles. Determining mechanisms that promote or limit regeneration in certain life cycle stages may pinpoint the most critical factors for successful regeneration and suggest strategies for reverse-engineering regenerative responses in therapeutic settings. In contrast to many mammalian systems, which typically show a loss of regenerative abilities with age, planarian flatworms remain highly regenerative throughout adulthood. The robust reproductive and regenerative capabilities of the planarian Schmidtea polychroa (Spol) make them an ideal model to determine when and how regeneration competence is established during development. We report that Spol gradually acquires whole body regenerative abilities during late embryonic and early juvenile stages. Posterior (tail) regenerative abilities are constitutive, whereas anterior (head) regenerative abilities are dependent on developmental stage, tissue composition of the amputated fragment, and axial position of the cut plane. Stem-like cells are required, but not sufficient, for onset of head regeneration ability. We propose that regulation of main body axis reset, specifically the ability to remake an anterior organizing center, is a rate-limiting factor for establishment of whole-body regeneration competence. Supporting this hypothesis, knock-down of the canonical Wnt pathway effector Spol {beta}-catenin-1, a posterior determinant, induces precocious head regeneration under conditions that are normally head regeneration incompetent. Our results suggest that regeneration competence emerges through interactions between cycling stem-like cells, the cellular source of new tissue, and developing adult tissue(s) harboring axial patterning information.

developmental biology↗

bioRxiv2023

Ets-1 transcription factor regulates glial cell regeneration and function in planarians

Glia play multifaceted roles in nervous systems in response to injury. Depending on the species, extent of injury, and glial cell type in question, glia can help or hinder the regeneration of neurons. Studying glia in the context of successful regeneration could reveal key features of pro-regenerative glia that could be exploited for improvement of human therapies. Planarian flatworms completely regenerate their nervous systems after injury--including glia--and thus provide a strong model system with which to explore glia in the context of regeneration. Here, we report that planarian glia regenerate after neurons and that glia require neural structures to regenerate near the eyespot. We find that the planarian transcription factor-encoding gene ets-1 promotes glial cell maintenance and regeneration. We also find that ets-1(RNAi) impairs nervous system architecture, neuronal gene expression, and animal behavior. Taken together, the discovery of ets-1 as a regulator of glial persistence presents a critical first step in understanding glial regulation and potential roles of glia in planarian neurobiology. More importantly, we elucidate interrelationships between glia and neurons in the context of robust neural regeneration.

developmental biology↗