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Lilley, K.

Publications and source records attributed to Lilley, K..

5 recordsLinked to original sources

Robust analysis of comparative subcellular omics with complex designs

Subcellular omics technologies now allow us to obtain insights into steady-state localisation and re-localisation of biomolecules in high-throughput. However, robust analysis of these experiments can be slow and challenging. Here, we show that existing approaches to differential localisation fall into two classes, marker-dependent and marker-free, that fail for fundamentally different statistical reasons, with failure modes that are not completely overlapping. We exploit this observation in SANDLE (statistical analysis of differential localisation experiments), which combines a marker-dependent generative model of subcellular niches with a marker-free regression test for changes in fractionation profiles. This dual strategy provides better control of false positives, up to 100-fold reduction in analysis time, and accommodates more complex experimental designs than existing methods. We demonstrate SANDLEs versatility across a wide range of subcellular omics experiments, including drug-treatment responses, cross-species and life-cycle comparisons, post-translationally modified proteoforms, and RNA re-localisation. Coanalysing transcriptome and proteome dynamics during the unfolded protein response, we further reveal lncRNAs whose steady-state localisation is condition-dependent. By addressing key methodological limitations, SANDLE enables broad applications of subcellular omics from fundamental biology to clinical research.

biochemistry↗

ROS responsive Aux/IAA multimerization modulates auxin responses

Reactive oxygen species (ROS) function as key signals in plants to enable adaptation to environmental stresses. Plant roots respond to transient water stress by temporarily ceasing branching using the acclimative response xerobranching1. In this study, we report that a rapid ROS burst regulates Xerobranching by inducing multimerization of auxin repressor protein IAA3/SHY2. Mutations in specific cysteine residues in IAA3/SHY2 disrupt redox-mediated multimerization and interaction with co-repressor TPL, but not with auxin response partner ARF7 and auxin receptor TIR1. ROS-mediated oligomerization of IAA3/SHY2 is required for efficient ARF mediated target gene repression during Xerobranching and lateral root emergence. We demonstrate that AUX/IAA proteins vary in their redox mediated multimerization, revealing a new auxin response regulatory mechanism that directly connects ROS sensing to auxin signalling. Our study reveals how ROS, auxin and water stress intersect to shape acclimative responses in plant roots and maintain their phenotypic plasticity.

plant biology↗

Characterisation of protein isoforms encoded by the Drosophila Glycogen Synthase Kinase 3 gene shaggy

The Drosophila shaggy gene (sgg, GSK-3) encodes multiple protein isoforms with serine/threonine kinase activity and is a key player in diverse developmental signalling pathways. Currently it is unclear whether different Sgg proteoforms are similarly involved in signalling or if different proteoforms have distinct functions. We used CRISPR/Cas9 genome engineering to tag eight different Sgg proteoform classes and determined their localization during embryonic development. We performed proteomic analysis of the two major proteoform classes and generated mutant lines for both of these for transcriptomic and phenotypic analysis. We uncovered distinct tissue-specific localization patterns for all of the tagged proteoforms we examined, most of which have not previously been characterised directly at the protein level, including one proteoform initiating with a non-standard codon. Collectively this suggests complex developmentally regulated splicing of the sgg primary transcript. Further, affinity purification followed by mass spectrometric analyses indicate a different repertoire of interacting proteins for the two major proteoform classes we examined, one with ubiquitous expression (Sgg-PB) and one with nervous system specific expression (Sgg-PA). Specific mutation of these proteoforms shows that Sgg-PB performs the well characterised maternal and zygotic segmentations functions of the sgg locus, while Sgg-PA mutants show adult lifespan and locomotor defects consistent with its nervous system localisation. Our findings provide new insights into the role of GSK-3 proteoforms and intriguing links with the GSK-3 and GSK-3{beta} encoded by independent vertebrate genes. Our analysis suggests that different protein isoforms generated by alternative splicing perform distinct functions.

genetics↗

ScanningSWATH enables ultra-fast proteomics using high-flow chromatography and minute-scale gradients

Bridging genotype to phenotype, the proteome has increasingly become of major importance to generate large, longitudinal sample series for data-driven biology and personalized medicine. Major improvements in laboratory automation, chromatography and software have increased the scale and precision of proteomics. So far missing are however mass spectrometric acquisition techniques that could deal with very fast chromatographic gradients. Here we present scanning SWATH, a data-independent acquisition (DIA) method, in which the DIA-typical stepwise windowed acquisition is replaced by a continuous movement of the precursor isolation window. Scanning SWATH accelerates the duty cycles to a few hundreds of milliseconds, and enables precursor mass assignment to the MS2 fragment traces for improving true positive precursor identification in fast proteome experiments. In combination with 800 {micro}L/min high-flow chromatography, we report the quantification of 270 precursors per second, increasing the precursor identifications by 70% or more compared to previous methods. Scanning SWATH quantified 1,410 Human protein groups in conjunction with chromatographic gradients as fast as 30 seconds, 2,250 with 60-second gradients, and 4,586 in conjunction with 5-minute gradients. At high quantitative precision, our method hence increases the proteomic throughput to hundreds of samples per day per mass spectrometer. Scanning SWATH hence enables a broad range of new proteomic applications that depend on large numbers of cheap yet quantification precise proteomes.

systems biology↗

Tracking the embryonic stem cell transition from ground state pluripotency

Mouse embryonic stem (ES) cells are locked into self-renewal by shielding from inductive cues. Release from this ground state in minimal conditions offers a system for delineating developmental progression from naive pluripotency. Here we examined the initial transition of ES cells. The population behaves asynchronously. We therefore exploited a short-half-life Rex1::GFP reporter to isolate cells either side of exit from naive status. Extinction of ES cell identity in single cells is acute. It occurs only after near-complete elimination of naive pluripotency factors, but precedes appearance of lineage specification markers. Cells newly departed from the ES cell state exhibit global transcriptome features consistent with features of early post-implantation epiblast and distinct from primed epiblast. They also exhibit a genome-wide increase in DNA methylation, intermediate between early and late epiblast. These findings are consistent with the proposition that naive cells transition to a discrete formative phase of pluripotency preparatory to lineage priming.\n\nHighlightsO_LIThe Rex1 destabilized GFP reporter demarcates naive pluripotency.\nC_LIO_LIExit from the naive state is asynchronous in the population.\nC_LIO_LITransition is relatively acute in individual cells and precedes lineage priming.\nC_LIO_LITranscriptome and DNA methylome reflect events in the pre-gastrulation embryo.\nC_LI

developmental biology↗