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Davey, K.

Publications and source records attributed to Davey, K..

5 recordsLinked to original sources

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↗

Interrogation of RNA-protein interaction dynamics in bacterial growth

Characterising RNA-protein interaction dynamics is fundamental to understand how bacteria respond to their environment. In this study, we have analysed the dynamics of 91% of the Escherichia coli expressed proteome and the RNA-interaction properties of 271 RNA-binding proteins (RBPs) at different growth phases. We find that 68% of RBPs differentially bind RNA across growth phases and characterise 17 previously unannotated proteins as bacterial RBPs including YfiF, a ncRNA-binding protein. While these new RBPs are mostly present in Proteobacteria, two of them have human orthologs in the form of mitochondrial proteins associated with rare metabolic disorders. Moreover, we reveal novel RBP functions for proteins such as the chaperone HtpG, a new stationary phase tRNA-binding protein. Altogether, we provide the first dynamic RBPome of a bacterium, showcasing how this approach can reveal the function of uncharacterised proteins, and identify critical RNA-protein interactions for cell growth which could inform new antimicrobial therapies.

microbiology↗

Single nuclear transcriptional signatures of dysfunctional brain vascular homeostasis in Alzheimer's disease

Brain perfusion and normal blood brain barrier integrity are reduced early in Alzheimers disease (AD). We performed single nucleus RNA sequencing of vascular cells isolated from AD and control brains to characterise pathological transcriptional signatures. We found that endothelial cells (EC) are enriched for expression of genes associated with susceptibility to AD. EC transcriptional signatures identified mechanisms for impaired {beta}-amyloid clearance. Evidence for immune activation was found with upregulation of interferon signalling genes in EC and in pericytes (PC). Transcriptional signatures suggested dysregulation of vascular homeostasis and angiogenesis with upregulation of pro-angiogenic signals (HIF1A) and metabolism in EC, but downregulation of homeostatic growth factor pathways (VEGF, EGF, insulin) in EC and PC and of extracellular matrix genes in fibroblasts (FB). Our genomic dissection of vascular cell risk gene enrichment suggests a potentially causal role for EC and defines transcriptional signatures associated with microvascular dysfunction in AD.

neuroscience↗

Diverse human astrocyte and microglial transcriptional responses to Alzheimer's pathology

To better define roles that astrocytes and microglia play in Alzheimers disease (AD), we used single-nuclei RNA sequencing to comprehensively characterize transcriptomes in astrocyte and microglia nuclei isolated post mortem from neuropathologically-defined AD and control brains with a range of amyloid-beta and phospho-tau (pTau) pathology. Significant differences in glial gene expression (including AD risk genes expressed in astrocytes [CLU, MEF2C, IQCK] and microglia [APOE, MS4A6A, PILRA]) were correlated with tissue amyloid and pTau expression. Astrocytes were enriched for proteostatic, inflammatory and metal ion homeostasis pathways. Pathways for phagocytosis, proteostasis and autophagy were highly enriched in microglia and perivascular macrophages. Gene co-expression analyses revealed potential functional associations of soluble biomarkers of AD in astrocytes (CLU) and microglia (GPNMB). Our work highlights responses of both astrocytes and microglia for pathological protein clearance and inflammation, as well as glial transcriptional diversity in AD.

neuroscience↗

A flexible microfluidic system for single-cell transcriptome profiling elucidates phased transcriptional regulators of cell cycle

Single cell transcriptome profiling has emerged as a breakthrough technology for the high-resolution understanding of complex cellular systems. Here we report a flexible, cost-effective and user-friendly droplet-based microfluidics system, called the Nadia Instrument, that can allow 3 mRNA capture of [~]50,000 single cells or individual nuclei in a single run. The precise pressure-based system demonstrates highly reproducible droplet size, low doublet rates and high mRNA capture efficiencies that compare favorably in the field. Moreover, when combined with the Nadia Innovate, the system can be transformed into an adaptable setup that enables use of different buffers and barcoded bead configurations to facilitate diverse applications. Finally, by 3 mRNA profiling asynchronous human and mouse cells at different phases of the cell cycle, we demonstrate the systems ability to readily distinguish distinct cell populations and infer underlying transcriptional regulatory networks. Notably this identified multiple transcription factors that had little or no known link to the cell cycle (e.g. DRAP1, ZKSCAN1 and CEBPZ). In summary, the Nadia platform represents a promising and flexible technology for future transcriptomic studies, and other related applications, at cell resolution.

genomics↗