@article {68503, title = {Brain-wide measurement of protein turnover with high spatial and temporal resolution}, journal = {bioRxiv}, year = {2022}, month = {2022 Nov 13}, abstract = {

Cells regulate function by synthesizing and degrading proteins. This turnover ranges from minutes to weeks, as it varies across proteins, cellular compartments, cell types, and tissues. Current methods for tracking protein turnover lack the spatial and temporal resolution needed to investigate these processes, especially in the intact brain, which presents unique challenges. We describe a pulse-chase method (DELTA) for measuring protein turnover with high spatial and temporal resolution throughout the body, including the brain. DELTA relies on rapid covalent capture by HaloTag of fluorophores that were optimized for bioavailability\ in vivo. The nuclear protein MeCP2 showed brain region- and cell type-specific turnover. The synaptic protein PSD95 was destabilized in specific brain regions by behavioral enrichment. A novel variant of expansion microscopy further facilitated turnover measurements at individual synapses. DELTA enables studies of adaptive and maladaptive plasticity in brain-wide neural circuits.

}, doi = {10.1101/2022.11.12.516226}, url = {https://doi.org/10.1101/2022.11.12.516226}, author = {Boaz Mohar and Jonathan B. Grimm and Ronak Patel and Timothy A. Brown and Paul Tillberg and Luke D. Lavis and Nelson Spruston and Karel Svoboda} } @article {66029, title = {Visualizing cellular and tissue ultrastructure using Ten-fold Robust Expansion Microscopy (TREx)}, journal = {eLife}, year = {2022}, month = {2022 Feb 18}, abstract = {

Expansion microscopy (ExM) is a powerful technique to overcome the diffraction limit of light microscopy that can be applied in both tissues and cells. In ExM, samples are embedded in a swellable polymer gel to physically expand the sample and isotropically increase resolution in x, y and z. The maximum resolution increase is limited by the expansion factor of the polymer gel, which is four-fold for the original ExM protocol. Variations on the original ExM method have been reported that allow for greater expansion factors, for example using iterative expansion, but at the cost of ease of adoption or versatility. Here, we systematically explore the ExM recipe space and present a novel method termed Ten-fold Robust Expansion Microscopy (TREx) that, like the original ExM method, requires no specialized equipment or procedures to carry out. We demonstrate that TREx gels expand ten-fold, can be handled easily, and can be applied to both thick tissue sections and cells enabling high-resolution subcellular imaging in a single expansion step. We show that applying TREx on antibody-stained samples can be combined with off-the-shelf small molecule stains for both total protein and membranes to provide ultrastructural context to subcellular protein localization.

}, doi = {https://doi.org/10.1101/2021.02.03.428837}, author = {Hugo G.J. Damstra and Boaz Mohar and Mark Eddison and Anna Akhmanova and Lukas C. Kapitein and Paul W. Tillberg} }