Biology subjects

Jones, M. K.

Publications and source records attributed to Jones, M. K..

7 recordsLinked to original sources

bioRxiv2026

A combinatorial pre-mRNP retention factor network couples nuclear speckle architecture to splicing quality control

Cells must prevent incompletely spliced transcripts from entering the cytoplasm, yet how splicing status is recognized and converted into selective nuclear retention remains unclear. Here, we identify a network of RNA-binding proteins that retain pre-mRNPs within nuclear speckles. Proteomic analysis of splicing intermediates accumulated in nuclear speckles identified a set of retention factors including BCLAF1, THRAP3 and SRSF7 that anchor pre-mRNPs to the SON scaffold and are required for pre-mRNP retention in speckles. Distinct RNA-binding patterns and transcript-specific retention factor requirements suggest that multiple mRNP features tune retention combinatorially. Super-resolution imaging revealed that the SON and SRRM2 speckle scaffolds form interdigitated networks with RNA enriched along networks and within interstitial speckle lumens. This architecture remodels in response to pre-mRNP load and is disrupted upon depletion of retention factors. Together, these findings define a pre-mRNP quality-control pathway that links splicing state to nuclear retention and the dynamic organization of nuclear speckles.

cell biology↗

bioRxiv2025

Cracking the egg: Isolation and discovery of distinct nonvesicular extracellular particles from Schistosoma mansoni eggs

Extracellular particles (EPs) derived from helminths are emerging as promising immunomodulatory agents, yet their heterogeneity challenges reproducible purification and characterisation. This study focused on purifying and characterising extracellular particles (EPs) from Schistosoma mansoni eggs using tangential flow filtration (TFF) and differential ultracentrifugation (dUC). Contrary to expectations, cryogenic transmission electron microscopy (cryoTEM) revealed that egg-derived EPs are nonvesicular (5-30 nm) nanoparticles (eggNPs) rather than membrane-bound extracellular vesicles. TFF demonstrated superior performance over dUC, yielding higher recovery (76.19% vs. 38.90%), greater purity, and lower endotoxin contamination. Despite limitations in standard protein quantification methods, enriched protein profiles and detection of S. mansoni tetraspanin-2 in TFF-purified eggNPs highlights their distinct molecular signatures. The study also identified contaminants in cryopreservation buffers, underscoring the need for optimised storage conditions. Compared to dUC, TFF preserved particle integrity, with cryoTEM images showing fewer aggregates and distinct EggNP morphology. This work proposes TFF as a scalable and reproducible method for isolating S. mansoni-derived eggNPs, providing a foundation for their exploration as immunomodulatory agents. These findings not only expand the understanding of helminth EPs but also emphasise their therapeutic potential, particularly in inflammatory and immune-dysregulation disorders.

molecular biology↗

bioRxiv2024

Widespread occurrence of benzimidazole resistance SNPs in the canine hookworm, Ancylostoma caninum, in Australia

Canine hookworm (Ancylostoma caninum), a gastrointestinal nematode of domestic dogs, principally infects the small intestine of dogs and has the potential to cause zoonotic disease. In greyhounds and pet dogs in the USA, A. caninum has been shown to be resistant to multiple anthelmintics. We conducted a molecular survey of benzimidazole resistance in A. caninum from dogs at veterinary diagnostic centers in Australia and New Zealand. First, we implemented an internal transcribed spacer (ITS)-2 rDNA deep amplicon metabarcoding sequencing approach to ascertain the species of hookworms infecting dogs in the region. Then, we evaluated the frequency of the canonical F167Y and Q134H isotype-1 {beta}-tubulin mutations, which confer benzimidazole resistance, using the same sequencing approach. The most detected hookworm species in diagnostic samples was A. caninum (90%; 83/92); the related Northern hookworm (Uncinaria stenocephala) was identified in 11% (10/92) of the diagnostic samples. There was a single sample with coinfection by A. caninum and U. stenocephala. Both isotype-1 {beta}-tubulin mutations were present in A. caninum, 49% and 67% for Q134H and F167Y, respectively. Mutation F167Y in the isotype-1 {beta}-tubulin mutation was recorded in U. stenocephala for the first known time. Canonical benzimidazole resistance codons 198 and 200 mutations were absent. Egg hatch assays performed on a subset of the A. caninum samples showed significant correlation between 50% inhibitory concentration (IC50) to thiabendazole and F167Y, with an increased IC50 for samples with >75% F167Y mutation. We detected 14% of dogs with >75% F167Y mutation in A. caninum. Given that these samples were collected from dogs across various regions of Australia, the present study suggests that benzimidazole resistance in A. caninum is widespread. Therefore, to mitigate the risk of resistance selection and further spread, adoption of a risk assessment-based approach to limit unnecessary anthelmintic use should be a key consideration for future parasite control.

microbiology↗

bioRxiv2022

CRISPR interference for Sequence-Specific Regulation of Fibroblast Growth Factor Receptor A in Schistosoma mansoni

Employing the flatworm parasite Schistosoma mansoni as a model, we report the first application of CRISPR interference (CRISPRi) in parasitic helminths for loss-of-function targeting the SmfgfrA gene which encodes the stem cell marker, fibroblast growth factor receptor A. SmFGFRA is essential for maintaining schistosome stem cells and critical in the schistosome-host interplay. The SmfgfrA gene was targeted in S. mansoni adult worms, eggs and schistosomula using a catalytically dead Cas9 (dCas9) fused to a transcriptional repressor KRAB. We showed that SmfgfrA repression resulted in considerable phenotypic differences in the modulated parasites compared with controls, including reduced levels of SmfgfrA transcription and decreased protein expression of SmFGFRA, a decline in EdU (thymidine analog 5-ethynyl-2-deoxyuridine, which specifically stains schistosome stem cells) signal, and an increase in cell apoptosis. Notably, reduced SmfgfrA transcription was evident in miracidia hatched from SmfgfrA-repressed eggs, and resulted in a significant change in miracidial behavior, indicative of a durable repression effect caused by CRISPRi. Intravenous injection of mice with SmfgfrA-repressed eggs resulted in granulomas that were markedly reduced in size and a decline in the level of serum IgE, emphasizing the importance of SmFGFRA in regulating the host immune response induced during schistosome infection. Our findings show the feasibility of applying CRISPRi for effective, targeted transcriptional repression in schistosomes, and provide the basis for employing CRISPRi to selectively perturb gene expression in parasitic helminths on a genome-wide scale.

molecular biology↗

bioRxiv2022

Bone Morphogenetic Protein (BMP) signaling regulates germline stem cell self-renewal in the newly formed Drosophila testis stem cell niche

Bone morphogenetic proteins (BMPs) are a group of multifunctional cytokines and metabologens highly conserved in the transforming growth factor-{beta} (TGF-{beta}) superfamily. BMPs have an established role in controlling cell fate and tissue morphogenesis in a diverse range of organisms and are known to maintain stem cells in adult Drosophila testes. Additional studies in embryonic and larval testes suggest BMP regulates germ cell behavior. However, the roles of BMP signaling in controlling testis stem cell formation have yet to be directly examined. Here, we explore the pattern of BMP activation during embryonic testis niche morphogenesis as well as niche maturation in larval testes. We also assess the impact of altered BMP signaling on these stages of development. Our data suggest that BMP signaling is critical for promoting germ cell identity in primordial germ cells during embryonic niche formation. During niche maturation, we also find that that BMP signaling is both necessary and sufficient for maintenance of a self- renewing germline stem cell (GSC) population, and that newly formed cyst stem cells (CySCs) are a source of BMP activating ligand. As development progresses, however, BMP activation is no longer sufficient to alter GSC self-renewal. Collectively, our work promotes a more thorough understanding of BMP as a key mechanism controlling stem cell development in Drosophila testes that has implications for the development of other organ systems.

developmental biology↗

bioRxiv2022

Adenosine A2A Receptor (A2AR) agonists improve survival in K28-hACE2 mice following SARS CoV-2 infection

Effective and available therapies for the treatment of COVID-19 disease are limited. Apadenoson is a highly potent selective anti-inflammatory adenosine A2A receptor (A2AR) agonist and potential treatment option for COVID-19 patients. Apadenoson, when administered after infection with SARS CoV-2, was found to decrease weight loss, improve clinical symptoms, reduce levels of a several proinflammatory cytokines and chemokines in bronchial lavage (BAL) fluid, and promote increased survival in K18hACE2 transgenic mice. Of note, administering apadenoson after, but not prior to Covid-19 infection, caused a rapid decrease in lung viral burden. The work presented provides the foundation for further examination of these drugs as a therapy option for COVID-19. SummaryApadenoson therapy improves COVID-19 outcome

microbiology↗

bioRxiv2021

Human norovirus infection of primary B cells triggers immune activation in vitro

Human norovirus (HNoV) is a global health and socio-economic burden, estimated to infect every individual at least five times during their lifetime. The underlying mechanism for the potential lack of long-term immune protection from HNoV infections is not understood and prompted us to investigate HNoV susceptibility of primary human B cells and its functional impact. Primary B cells isolated from whole-blood were infected with HNoV-positive stool samples and harvested 3 days post infection (dpi) to assess viral RNA yield by RT-qPCR. A 3-18 fold increase in HNoV RNA yield was observed in 50-60% donors. Infection was further confirmed in B cells derived from splenic and lymph node biopsies. Next, we characterized infection of whole-blood derived B cells by flow cytometry in specific functional B cell subsets (naive CD27-IgD+, memory switched CD27+IgD-, memory unswitched CD27+IgD+ and double-negative CD27-IgD-). While susceptibility of subsets was similar, we observed changes in B cell subsets distribution upon infection that were recapitulated after treatment with HNoV virus-like particles and mRNA encoding for HNoV NS1-2 protein. Importantly, treatment of immortalized BJAB B cell lines with the predicted recombinant NS1 protein triggered cell proliferation, increased ATP production, and induced metabolic changes, as detected by means of CFSE/Ki67 staining, seahorse analysis and metabolomics, respectively. These data demonstrate the susceptibility of primary B cells to HNoV infection and suggest that the secreted NS1 protein affects B cell function, proliferation and metabolism in vitro, which could have implications for viral pathogenesis and immune response in vivo. ImportanceHuman norovirus (HNoV) is the most prevalent causative agent of gastroenteritis worldwide. Infection results in a self-limiting disease that can become chronic and severe in the immunocompromised, elderly and infants. There are currently no approved therapeutic and preventative strategies to limit the health and socio-economic burden associated with HNoV infections. Moreover, HNoV does not elicit life-long immunity as repeat infections are common, presenting a challenge for vaccine development. Given the importance of B cells for humoral immunity, we investigated susceptibility and impact of HNoV infection on human B cells. We found that HNoV replicates in human primary B cells derived from blood, spleen and lymph nodes specimens and induces functional changes in B cells, mediated in part by the non-structural protein NS1. Because of the secreted nature of NS1, we put forward the hypothesis that HNoV infection can modulate bystander B cell function with potential implications in systemic immune response.

microbiology↗