Project description
Encapsulin nanospheres as novel electron microscopy gene reporters
Encapsulins are small bacterial proteins that automatically assemble into nanospheres where chemical reactions run without toxic effects on cells. Nanospheres of different structure, diameter and functionalisations can be created within living cells via genetic programming. The encapsulation of metal-binding cargo proteins inside the nanospheres creates gene reporters for electron microscopy (EM) with robust and spatially precise contrast for applications in mammalian cells. The EU-funded EMcapsulins project will create the first set of multiplexed genetic reporters for EM to study structural brain circuit diagrams (connectomes) in order to obtain crucial information on the neuronal type and activation history. These modular encapsulated reporters will deliver the bridging technology between time-resolved light microscopy measurements of neuronal activation dynamics and structural EM connectomics data.
Objective
The biological engineering project EMcapsulins will create the first suite of multiplexed genetic reporters for electron microscopy (EM) to augment today’s merely structural brain circuit diagrams (connectomes) with crucial information on neuronal type and activation history.
My team will generate this new toolbox based on genetically encoded nanocompartments of the prokaryotic ‘encapsulin’ family that we have recently shown to enable genetically controlled compartmentalization of multicomponent processes in mammalian cells.
By encapsulating metal-organizing cargo proteins in the lumen of the semi-permeable encapsulin nanospheres, they serve as fully genetic EM gene reporters (EMcapsulins) that provide robust and spatially precise contrast by conventional EM in mammalian cells.
To enable geometric multiplexing in EM in analogy to multi-color light microscopy, we will explore the large geometrical feature space of EMcapsulins to establish three core Functionalities:
① different shell structures and diameters,
② modular and tunable shell functionalizations, and
③ multiplexed and triggered cargo loading.
We will combine these Functionalities to produce geometrically multiplexed EMcapsulin markers of neuronal identity in serial EM (Application ❶).
We will also engineer EMcapsulin reporters for activity-dependent gene expression, calcium signaling, and synaptic activity that can ‘write’ geometrically encoded records of neuronal activation history into EM connectomics data (Application ❷).
These ‘multi-color’ and modular EMcapsulin markers and reporters deliver the missing bridging technology between time-resolved light microscopy measurements of neuronal activation dynamics and structural EM connectomics data.
EMcapsulin technology will convert structural to functional EM connectomes to enable a systematic analysis of how brains write molecular signaling dynamics into structural patterns to store information for later retrieval.
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Programme(s)
Funding Scheme
ERC-COG - Consolidator GrantHost institution
80333 Muenchen
Germany