1.
A light-gated potassium channel for sustained neuronal inhibition.
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Alberio, L
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Locarno, A
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Saponaro, A
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Romano, E
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Bercier, V
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Albadri, S
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Simeoni, F
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Moleri, S
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Pelucchi, S
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Porro, A
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Marcello, E
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Barsotti, N
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Kukovetz, K
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Boender, AJ
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Contestabile, A
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Luo, S
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Moutal, A
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Ji, Y
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Romani, G
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Beltrame, M
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Del Bene, F
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Di Luca, M
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Khanna, R
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Colecraft, HM
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Pasqualetti, M
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Thiel, G
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Tonini, R
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Moroni, A
Abstract:
Currently available inhibitory optogenetic tools provide short and transient silencing of neurons, but they cannot provide long-lasting inhibition because of the requirement for high light intensities. Here we present an optimized blue-light-sensitive synthetic potassium channel, BLINK2, which showed good expression in neurons in three species. The channel is activated by illumination with low doses of blue light, and in our experiments it remained active over (tens of) minutes in the dark after the illumination was stopped. This activation caused long periods of inhibition of neuronal firing in ex vivo recordings of mouse neurons and impaired motor neuron response in zebrafish in vivo. As a proof-of-concept application, we demonstrated that in a freely moving rat model of neuropathic pain, the activation of a small number of BLINK2 channels caused a long-lasting (>30 min) reduction in pain sensation.
2.
Optogenetics. Engineering of a light-gated potassium channel.
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Cosentino, C
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Alberio, L
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Gazzarrini, S
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Aquila, M
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Romano, E
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Cermenati, S
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Zuccolini, P
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Petersen, J
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Beltrame, M
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Van Etten, JL
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Christie, JM
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Thiel, G
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Moroni, A
Abstract:
The present palette of opsin-based optogenetic tools lacks a light-gated potassium (K(+)) channel desirable for silencing of excitable cells. Here, we describe the construction of a blue-light-induced K(+) channel 1 (BLINK1) engineered by fusing the plant LOV2-Jα photosensory module to the small viral K(+) channel Kcv. BLINK1 exhibits biophysical features of Kcv, including K(+) selectivity and high single-channel conductance but reversibly photoactivates in blue light. Opening of BLINK1 channels hyperpolarizes the cell to the K(+) equilibrium potential. Ectopic expression of BLINK1 reversibly inhibits the escape response in light-exposed zebrafish larvae. BLINK1 therefore provides a single-component optogenetic tool that can establish prolonged, physiological hyperpolarization of cells at low light intensities.