Circuit mapping requires knowledge of both structural and functional connectivity between cells. Although optical tools have been made to assess either the morphology and projections of neurons or their activity and functional connections, few probes integrate this information. We have generated a family of photoactivatable genetically encoded Ca 2+ indicators that combines attributes of high-contrast photolabeling with high-sensitivity Ca 2+ detection in a single-color protein sensor. We demonstrated in cultured neurons and in fruit fly and zebrafish larvae how single cells could be selected out of dense populations for visualization of morphology and high signal-to-noise measurements of activity, synaptic transmission and connectivity. Our design strategy is transferrable to other sensors based on circularly permutated GFP (cpGFP).
Bibliographical noteFunding Information:
We thank C. Stanley and Z. Fu for help with molecular biology, H. Aaron for technical help with microscopy and C. Chang for fluorimeter use. We also thank R.Y. Tsien (University of California, San Diego) for the pRSETB vector, J.L. Brusés (University of Kansas) for the generous gift of the mnx1-GAL4 construct and D. Friedmann for generating the mnx1-GAL4 transgenic zebrafish line. The work was supported by US National Science Foundation (NSF) Graduate Research Fellowship (1106400; Z.L.N.), NSF Major Research Instrumentation (1041078; E.Y.I.), US National Institute of General Medical Sciences (R01 GM068552; J.C.L.) and US National Institutes of Health Nanomedicine Development Center for the Optical Control of Biological Function (2PN2EY01824; E.Y.I.).
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