Biology subjects

Kane, L.

Publications and source records attributed to Kane, L..

4 recordsLinked to original sources

bioRxiv2026

Unique mushroom spine morphology signature in cocaine relapse ensembles in rat nucleus accumbens core

Fos-expressing neuronal ensembles in nucleus accumbens (NAc) are selectively activated by drug-associated cues and shown to play a causal role in drug-cue memories. Many unique molecular and cellular alterations have been identified in these ensembles and thought to be components of an engram encoding the memory; however, spine morphology alterations on these ensembles have rarely been examined. Here, we examined alterations of identified spine types on Fos-expressing neurons in NAc core that were selectively activated by drug-associated cues during cocaine relapse. We combined Fos immunolabeling along with viral-based sparse GFP labeling to identify Fos-positive and Fos-negative neurons with distinguishable dendrites and quantified spine composition, densities and interspine intervals (ISIs) for all spine types, and head and neck diameters of mushroom spines. ISIs and head and neck diameters of mushroom spines were altered on Fos-positive (versus Fos-negative) neurons activated during cue-induced cocaine relapse. Critically, these alterations were not found on Fos-positive neurons activated by exposure to a novel context on relapse test day, despite having identical cocaine self-administration histories. Based on previous work, this suggests these alterations were not simply due to acute activation of a randomly selected set of neurons on test day, but rather they were altered specifically on neurons selectively activated during cocaine self-administration training and then reactivated during relapse. Stubby spines and immature spines, including filopodia and thin spines, were not altered. Altogether, these mushroom spine alterations describe a unique spine morphology signature for a drug-cue memory in NAc neuronal ensembles selectively activated during cocaine relapse.

neuroscience↗

bioRxiv2021

Cohesin is required for long-range enhancer action

The mammalian genome is organised into topologically associating domains (TADs) that are formed through the process of cohesin-driven loop extrusion1-3 and whose extent is constrained at TAD boundaries by orientation-dependent CTCF binding4-7. The large regulatory landscapes of developmental genes frequently correspond to TADs, leading to the hypothesis that TADs and/or loop extrusion are important for enhancers to act on their cognate gene8,9. However, it has proven hard to interpret the consequences of experimental disruption of TADs or loop-extrusion on gene regulation3,6,10, in part because of the difficulty in distinguishing direct from indirect effects on enhancer-driven gene expression. By coupling acute protein degradation with synthetic activation by targeted transcription factor recruitment in mouse embryonic stem cells, here we show that cohesin, but not CTCF, is required for activation of a target gene by distant distal regulatory elements. Cohesin is not required for activation directly at the promoter or activation from an enhancer located closer to the gene. Our findings support the hypothesis that chromatin compaction mediated by cohesin-mediated loop extrusion allows for genes to be activated by regulatory elements that are located many hundreds of kilobases away in the linear genome but suggests that cohesin is dispensable for more genomically close enhancers.

genetics↗

bioRxiv2019

High-throughput phenotyping reveals expansive genetic and structural underpinnings of immune variation

By developing a high-density murine immunophenotyping platform compatible with high-throughput genetic screening, we have established profound contributions of genetics and structure to immune variation. Specifically, high-throughput phenotyping of 530 knockout mouse lines identified 140 monogenic \"hits\" (>25%), most of which had never hitherto been implicated in immunology. Furthermore, they were conspicuously enriched in genes for which humans show poor tolerance to loss-of-function. The immunophenotyping platform also exposed dense correlation networks linking immune parameters with one another and with specific physiologic traits. By limiting the freedom of individual immune parameters, such linkages impose genetically regulated \"immunological structures\", whose integrity was found to be associated with immunocompetence. Hence, our findings provide an expanded genetic resource and structural perspective for understanding and monitoring immune variation in health and disease.

immunology↗

bioRxiv2019

Developmentally regulated Shh expression is robust to TAD perturbations

Topologically Associating Domains (TADs) have been proposed to both guide and constrain enhancer activity. Shh is located within a TAD known to contain all its enhancers. To investigate the importance of chromatin conformation and TAD integrity on developmental gene regulation, we have manipulated the Shh TAD - creating internal deletions, deleting CTCF sites including those at TAD boundaries, as well as larger deletions and inversions of TAD boundaries. Chromosome conformation capture and fluorescence in situ hybridisation assays were used the investigate changes in chromatin conformation that result from these manipulations. Our data suggest that the substantial alteration of TAD structure has no readily detectable effect on Shh expression patterns during development - except where enhancers are deleted - and results in no detectable phenotypes. Only in the case of a larger deletion of one TAD boundary could some ectopic influence of the Shh limb enhancer be detected on a gene - Mnx1 in the neighbouring TAD. Our data suggests that, contrary to expectations, the developmental regulation of Shh expression is remarkably robust to TAD perturbations.

developmental biology↗