Biology subjects

Moore, S. A.

Publications and source records attributed to Moore, S. A..

8 recordsLinked to original sources

bioRxiv2026

Pathogenic variants of the mitochondrial copper chaperones SCO1 and SCO2 reshape their respective interactomes and disrupt cellular phospholipid metabolism

SCO1 and SCO2 are required for copper delivery to COX2, a copper-containing subunit of cytochrome c oxidase (COX), yet how mutations in these genes cause distinct, tissue-specific forms of human disease remains poorly understood. To gain further insight into the molecular underpinnings of this clinical heterogeneity, we used BioID to map the interactomes of four pathogenic SCO variants (SCO1 G132S, SCO1 P174L, SCO1 M294V and SCO2 E140K) and the wild-type proteins. While this approach identified many proteins common to both wild-type neighbourhoods, several potential interacting partners unique to each SCO protein were also observed that were consistent with their known roles in COX assembly. Follow-up analyses revealed that SCO1 interacts with COX16 and that this interaction is stabilized within the membrane by a coiled-coil helix-helix interface, with the soluble C-terminal region of COX16 physically bridging SCO1 and COX2 within a ternary complex to facilitate copper delivery. We further observed that COX16 abundance is relatively low in the brain and its association with SCO1 is most severely impaired by the M294V substitution associated with a fatal encephalopathy. Intriguingly, our BioID analyses also detected significant enrichment in each SCO neighbourhood for biosynthetic enzymes and lipases critical to phospholipid metabolism and found that the affinity for these candidate interactors was uniquely perturbed by various pathogenic variants of SCO1 and SCO2. Collectively, our data emphasize the potential of proximity labelling to further define the molecular roles of disease-causing variants that perturb mitochondrial function and suggest that SCO proteins impinge upon phospholipid metabolism.

molecular biology↗

bioRxiv2026

Regenerative Index reveals declining muscle regeneration in paediatric patients with Duchenne muscular dystrophy

BackgroundDuchenne muscular dystrophy (DMD) is a devastating disease manifested in skeletal muscle by repetitious myonecrosis and regeneration. Because the regenerative process is closely linked to the cumulative severity of muscle damage, which is variably distributed within and between muscle groups, accurately quantifying muscle regeneration has remained a significant challenge. MethodsMyofibers are delineated by immunostaining for laminin, and subsequent image analysis employed to generate a masked outline precisely within each myofiber boundary. Morphometric parameters including minimal Ferets diameter, cross-sectional area, and circularity were measured for each myofiber. In addition, the number of Pax7-expressing satellite cells were quantified. To evaluate regenerative activity, newly formed myofibers were identified by immunostaining for expression of embryonic myosin heavy chain (eMHC). Necrotic myofibers were enumerated by immunofluorescent detection of immunoglobulin G (IgG) infiltration. The Regenerative Index (RI) was calculated as the number of regenerating (eMHC+) myofibers divided by the number of necrotic (IgG+) myofibers. Determination of RI was performed on muscle biopsies from 10 boys with DMD and 3 non-DMD controls of similar age. ResultsA trend toward an increasing minimal Ferets diameter, cross-sectional area and circularity was observed with increasing age in DMD boys, with circularity showing the strongest trend. Furthermore, compared to DMD boys 7- to 8-years old, the boys 9- to 11-years old had significantly increased myofiber circularity. Pax7-expressing cells were significantly elevated in DMD boys compared to control boys of similar ages, without any observation of age-related changes. Notably, the Regenerative Index in DMD boys exhibited a pronounced decline between 7-11 years of age, and a significant inverse correlation between RI and age was observed. ConclusionsUsing eMHC and IgG immunostaining to calculate RI accurately assesses regeneration despite the variation in histopathologic severity between biopsies. This methodology demonstrated a significant negative correlation between RI and age of DMD boys from 7 to 11 years of age.

pathology↗

bioRxiv2025

Altered pseudostratified epithelial development of the lateral ventricle choroid plexus in Mllt11 mutants

The choroid plexuses (ChPs) are modified epithelial structures that penetrate all four cerebral ventricles and secrete cerebrospinal fluid. They consist of a central stroma that is vascularized with fenestrated blood vessels and connective tissue. The ChPs are of dual embryonic origin, with forebrain neuroepithelial cells contributing to the epithelial component and mesenchymal cells contributing to the stromal cells. The growth of the ChPs into the ventricular spaces is fueled by the migration and proliferation of neuroepithelial progenitor cells originating from the cortical hem. However, the genetic regulation of neuroepithelial progenitor (NEP) migration during ChP development is not well understood. Here we report the role of Mllt11 (Af1q/Tcf7c) in the formation of the ChP in part by regulating the migration of Otx1/2+ NEPs into the base of the fetal ChP, fueling its "treadmilling" growth into the lateral ventricle. We used Cux2iresCre/+ allele to selectively ablate Mllt11 in the developing cortical hem and its principal derivatives, the ChP and hippocampus. We discovered that Mllt11 mutants displayed thickened cuboid epithelial architecture of the ChP but maintained the epithelial organization of the outer layer of the ChP. This likely contributed to shorter lateral ventricle ChP stalks in Mllt11 cKO brains.

developmental biology↗

bioRxiv2023

Absence of SARS-CoV-2 in Wildlife of Northeastern Minnesota and Isle Royale National Park

We investigated the presence of SARS-CoV-2 in free-ranging wildlife populations in Northeastern Minnesota on the Grand Portage Indian Reservation and Isle Royale National Park. 120 nasal samples were collected from white-tailed deer, moose, gray wolves, and black bears monitored for conservation efforts during 2022-2023. Samples were tested for viral RNA by RT-qPCR using the CDC N1/N2 primer set. Our data indicate that no wildlife samples were positive for SARS-CoV-2 RNA. Continued surveillance is therefore crucial to better understand the changing landscape of zoonotic SARS-CoV-2 in the Upper Midwest.

microbiology↗

bioRxiv2023

Rapid molecular species identification of mammalian scat samples using nanopore adaptive sampling

AO_SCPLOWBSTRACTC_SCPLOWAccurate species identification is essential to mammalogy. Despite this necessity, rapid and accurate identification of cryptic, understudied, and elusive mammals remains challenging. Traditional barcoding of mitochondrial genes is standard for molecular identification but requires time-consuming wet-lab methodologies. Recent bioinformatic advancements for nanopore sequencing data offer exciting opportunities for non-invasive and field-based identification of mammals. Nanopore adaptive sampling (NAS), a PCR-free method, selectively sequences regions of DNA according to user-specified reference databases. Here, we utilized NAS to enrich mammalian mitochondrial genome sequencing to identify species. Fecal DNA extractions were sequenced from nine mammals, several collected in collaboration with Minnesota Tribal Nations, to demonstrate utility for NAS-barcoding of non-invasive samples. By mapping to the entire National Center for Biotechnology Information (NCBI) mammalian mitochondrial reference genome database and bioinformatically analyzing highly similar matches, we successfully produced species identifications for all of our fecal samples. Eight of nine species identifications matched previous PCR or animal/fecal morphological identifications. For the ninth species, our genetic data indicate a misidentification stemming from the original study. Our approach has a range of applications, particularly field-based wildlife research, conservation, disease surveillance, and monitoring of wildlife trade. Of importance to Minnesota tribes is invasive species monitoring, detections, and confirmation as climate impacts causes changes in biodiversity and shifts in species distributions. The rapid assessment techniques described here will be useful as new introductions and range expansions of native and invasive species may first be detected by the presence of signs such as scat rather than direct observations and will be helpful for chronically understaffed tribal natural resources agencies.

genomics↗

bioRxiv2022

Statistical Population Reconstruction of Moose (Alces alces) in Northeastern Minnesota using Integrated Population Models

Given recent and abrupt declines in the abundance of moose (Alces alces) throughout parts of Minnesota, accurately estimating statewide population trends and demographic parameters is a high priority for their continued management and conservation. Statistical population reconstruction using integrated population models provides a flexible framework for combining information from multiple studies across the state to produce robust estimates of population abundance, recruitment, and survival. We used this framework to combine aerial survey data and survival data from telemetry studies to recreate trends and demographics of moose in northeastern Minnesota, USA, from 2005 to 2020. Statistical population reconstruction confirmed the sharp decline in abundance from an estimated 7,841 (90% CI = 6,702-8,933) in 2009 to 3,386 (90% CI = 2,681-4,243) animals in 2013, but also indicated that abundance has remained relatively stable since then, except for a slight decline to 3,163 (90% CI = 2,403- 3,718) in 2020. Subsequent stochastic projection of the population from 2021 to 2030 suggests that this modest decline will continue for the next ten years. Both annual adult survival and per-capita recruitment (number of calves that survived to 1 year per adult female alive during the previous year) decreased substantially in years 2005 and 2019, from 0.902 (SE = 0.043) to 0.689 (SE = 0.061) and from 0.386 (SE = 0.030) to 0.303 (SE = 0.051), respectively. Sensitivity analysis revealed that moose abundance was more sensitive to fluctuations in adult survival than recruitment, leading us to conclude that the steep decline in 2013 was driven primarily by decreasing adult survival. Our analysis demonstrates the potential utility of using statistical population reconstruction to monitor moose population trends and to identify population declines more quickly. Future studies should focus on providing better estimates of per-capita recruitment, using pregnancy rates and calf survival, which can then be incorporated into reconstruction models to help improve estimates of population change through time.

ecology↗

bioRxiv2021

Mllt11 regulates the migration and neurite outgrowth of cortical projection neurons during development

The formation of connections within the mammalian neocortex is highly regulated by both extracellular guidance mechanisms and intrinsic gene expression programs. There are generally two types of cortical projection neurons: those that project locally and interhemispherically, and those that project to sub-cerebral structures such as the thalamus, hindbrain, and spinal cord. The regulation of cortical projection morphologies is not yet fully understood at the molecular level. Here we report a role for Mllt11 (Myeloid/lymphoid or mixed-lineage leukemia; translocated to chromosome 11/All1 Fused Gene From Chromosome 1q) in the migration and neurite outgrowth of callosal projection neurons during brain formation. We show that Mllt11 expression is exclusive to developing neurons and is enriched in the developing cortical plate, particularly during the formation of the upper or superficial cortical layers. In cultured primary cortical neurons, Mllt11 is detected in varicosities and growth cones as well as the soma. Using conditional loss-of-function and gain-of-function analysis we show that Mllt11 is a required for neuritogenesis and proper migration of upper layer cortical projection neurons. Loss of Mllt11 in the superficial cortex leads to a severe reduction in fibres crossing the corpus callosum, a progressive loss in the maintenance of upper layer projection neuron gene expression, and dysplasia of dendritic arborisation patterns. Proteomic analysis revealed that Mllt11 associates with cytoskeletal components including stabilized microtubules consistent with a role in neuronal migration and neuritogenesis. Taken together, our findings support a role for Mllt11 in promoting the formation of mature projection neuron morphologies and connectivity in the cerebral cortex.

developmental biology↗

bioRxiv2020

Mitochondrial copper and phosphate transporter specificity was defined early in the evolution of eukaryotes

Mitochondrial carrier family (MCF/SLC25) proteins are selective transporters that maintain the mitochondrial metabolome. Here we combine computational, biochemical and phenotypic approaches to understand substrate selectivity of SLC25A3. In mammals, SLC25A3 transports both copper and phosphate, yet in Saccharomyces cerevisiae the transport of these substrates is partitioned across two paralogs: PIC2, which transports copper, and MIR1, which transports phosphate. To understand whether the ancestral state of this transporter was a single promiscuous transporter that duplicated and gained selectivity, we explored the evolutionary relationships of PIC2 and MIR1 orthologs across the eukaryotic tree of life. Phylogenetic analyses reveal that PIC2-like and MIR1-like orthologs are present in all major eukaryotic supergroups, indicating that the gene duplication that created these paralogs occurred early in eukaryotic evolution. Frequent lineage-specific gene duplications and losses suggest that substrate specificity may be evolutionarily labile. To link this phylogenetic signal to protein function and resolve the residues involved in substrate selection, we used structural modelling and site-directed mutagenesis to identify PIC2 residues involved in copper and phosphate transport activities. Based on these analyses, we generated a Leu175Ala variant of mouse SLC25A3 that retains the ability to transport copper, but not phosphate, and rescues the cytochrome c oxidase defect in SLC25A3 knockout cells. Taken together, this work uses an evolutionary framework to uncover amino acids involved in substrate recognition by MCF proteins responsible for copper and phosphate transport.

evolutionary biology↗