Biology subjects

Bowen, C.

Publications and source records attributed to Bowen, C..

4 recordsLinked to original sources

bioRxiv2025

Natural variation in the oxytocin receptor gene predicts social observation in female prairie voles

Genetic variation in the oxytocin receptor gene (Oxtr) has been linked to differences in brain OXTR expression and long-term social bonds, but whether it shapes the moment-to-moment dynamics of early social interactions is unclear. Here we examined how the intronic Oxtr single nucleotide polymorphism (SNP) NT213739 in female prairie voles (Microtus ochrogaster) shapes their dynamic social interactions with an opposite-sex conspecific. Leveraging a computational pipeline to analyze the movements of freely interacting voles, we found that C/C females, which expressed higher OXTR levels in the nucleus accumbens than T/T females, spent more time socially observing novel males from a distance, especially early in interactions. This genotype-phenotype relationship persisted in multiple contexts, including the social preference test. Thus, natural Oxtr variation biases social observation in females toward unfamiliar males before bonds form, consistent with models where accumbens OXTR enhances the salience of social cues. These findings show that SNPs can shape subtle behavioral dimensions in early social encounters, with important implications for the role of oxytocin in the study of social attachment.

neuroscience↗

bioRxiv2023

Methylome-dependent transformation of emm1 group A streptococci

Genetic intractability presents a fundamental barrier to the manipulation of bacteria, hindering advancements in microbiological research. Group A Streptococcus (GAS), a lethal human pathogen currently associated with an unprecedented surge of infections world-wide, exhibits poor genetic tractability attributed to the activity of a conserved type 1 restriction modification system (RMS). RMS detect and cleave specific target sequences in foreign DNA that are protected in host DNA by sequence-specific methylation. Overcoming this "restriction barrier" thus presents a major technical challenge. Here we demonstrate for the first time that different RMS variants expressed by GAS give rise to genotype-specific and methylome-dependent variation in transformation efficiency. Further, we show that the magnitude of impact of methylation on transformation efficiency elicited by RMS variant TRDAG, encoded by all sequenced strains of the dominant and upsurge-associated emm1 genotype, is 100-fold greater than for all other TRD tested and is responsible for the poor transformation efficiency associated with this lineage. In dissecting the underlying mechanism, we developed an improved GAS transformation protocol whereby the restriction barrier is overcome by addition of the phage anti-restriction protein Ocr. This protocol is highly effective for TRDAG strains including clinical isolates representing all emm1 lineages, and will expedite critical research interrogating the genetics of emm1 GAS, negating the need to work in an RMS-negative background. These findings provide a striking example of the impact of RMS target sequence variation on bacterial transformation, and the importance of defining lineage-specific mechanisms of genetic recalcitrance. ImportanceUnderstanding the mechanisms by which bacterial pathogens are able to cause disease is essential to enable the targeted development of novel therapeutics. A key experimental approach to facilitate this research is the generation of bacterial mutants, through either specific gene deletions or sequence manipulation. This process relies on the ability to transform bacteria with exogenous DNA designed to generate the desired sequence changes. Bacteria have naturally developed protective mechanisms to detect and destroy invading DNA, and these systems severely impede the genetic manipulation of many important pathogens, including the lethal human pathogen group A Streptococcus (GAS). Many GAS lineages exist, of which emm1 is dominant among clinical isolates. Based on new experimental evidence, we identify the mechanism by which transformation is impaired in the emm1 lineage and establish an improved and highly efficient transformation protocol to expedite the generation of mutants.

microbiology↗

bioRxiv2022

Cellular proteomic profiling using proximity labelling by TurboID-NES in microglial and neuronal cell lines.

1.0Different brain cell types play distinct roles in brain development and disease. Molecular characterization of cell-specific mechanisms using cell type-specific approaches at the protein (proteomic) level, can provide biological and therapeutic insights. To overcome the barriers of conventional isolation-based methods for cell type-specific proteomics, in vivo proteomic labeling with proximity dependent biotinylation of cytosolic proteins using biotin ligase TurboID, coupled with mass spectrometry (MS) of labeled proteins, has emerged as a powerful strategy for cell type-specific proteomics in the native state of cells without need for cellular isolation. To complement in vivo proximity labeling approaches, in vitro studies are needed to ensure that cellular proteomes using the TurboID approach are representative of the whole cell proteome, and capture cellular responses to stimuli without disruption of cellular processes. To address this, we generated murine neuroblastoma (N2A) and microglial (BV2) lines stably expressing cytosolic TurboID to biotinylate the cellular proteome for downstream purification and analysis using MS. TurboID-mediated biotinylation captured 59% of BV2 and 65% of N2A proteomes under homeostatic conditions. TurboID expression and biotinylation minimally impacted homeostatic cellular proteomes of BV2 and N2A cells, and did not affect cytokine production or mitochondrial respiration in BV2 cells under resting or lipopolysaccharide (LPS)-stimulated conditions. These included endo-lysosome, translation, vesicle and signaling proteins in BV2 microglia, and synaptic, neuron projection and microtubule proteins in N2A neurons. The effect of LPS treatment on the microglial proteome was captured by MS analysis of biotinylated proteins (>500 differentially-abundant proteins) including increased canonical pro-inflammatory proteins (Il1a, Irg1, Oasl1) and decrease anti-inflammatory proteins (Arg1, Mgl2).

neuroscience↗

bioRxiv2018

Human IL-2 receptor β mutations associated with defects in immunity and peripheral tolerance

Interleukin-2, which conveys essential signals for effective immunity and immunological tolerance, operates through a heterotrimeric receptor comprised of , {beta} and {gamma} chains. Genetic deficiency of the or {gamma} chain causes debilitating disease. Here we identify human interleukin-2 receptor (IL-2R) {beta} chain (CD122) gene defects as a cause of life-threatening dysregulation of immunity and peripheral tolerance. We report homozygous mutations in the human IL-2R{beta} gene from four consanguineous families, comprising either recessive missense mutations in five children or an early stop-gain mutation in two deceased fetuses and a premature neonate. All patients surviving to childhood presented with autoantibodies, hypergammaglobulinemia, bowel inflammation, and dermatological abnormalities, as well as cytomegalovirus disease in most cases. Patient T lymphocytes lacked surface expression of IL-2R{beta} and were unable to normally respond to high-dose IL-2 stimulation. By contrast, patient natural killer (NK) cells retained partial IL-2R{beta} expression and cytotoxic function. IL-2R{beta} loss of function was recapitulated in a recombinant system, in which endoplasmic reticulum sequestration was revealed as the mechanism by which certain missense mutations cause disease. Hematopoietic stem cell transplant resulted in resolution of clinical symptoms in one patient. The hypomorphic nature of this disease highlights the significance of variable IL-2R{beta} expression in different lymphocyte subsets as a means of modulating immune function. Insights from these patients can inform the development of IL-2-based therapeutics for immunological diseases and cancer.

immunology↗