报告题目：Channelrhodopsin et al.: optogenetic actuators for non-invasive manipulation of organisms
报告时间：2017年5月19号（周五）14:30
报告地点：武汉光电国家实验室A101
报 告 人：Dr. Georg Nagel Julius-Maximilians-Universität Würzburg, Germany
邀 请 人：骆清铭教授
简介：Nagel教授是光敏通道ChR2的发现者，基因的克隆者。
Abstract：
The technique to manipulate via light-sensitive, genetically encoded proteins, cellular signalling and animal behaviour by illumination, is now called optogenetics. The breakthrough for optogenetics came with the Channelrhodopsins from the unicellular green alga C. reinhardtii which are Light-gated cation channels, allowing fast lightinduced depolarization of the plasma membrane (1,2). Mutations led to a slower photocycle and therefore to Channelrhodopsins with higher light sensitivity. Neuronal expression of Channelrhodopsin-2 (ChR2) yields Light-induced action potentials and Light-manipulated behaviour in C. elegans (3). The Light-activated chloride pump halorhodopsin (HR) from the archaeum Natronomonas pharaonis hyperpolarizes the plasma membrane and therefore allows Light-induced silencing of neurons (4). These two antagonistic rhodopsins may be expressed in the same cell and specifically activated with 460 nm light for ChR2 and 580 nm for HR. Recently we found a ChR2 mutant with increased expression and high light sensitivity (ChR2-XXL) which allows light modulation of previously non-responsive brain neurons in adult Drosphila flies, even without feeding the chromophor all-trans retinal (5). Recently new genes for opsins with an attached guanylyl cyclase domain were found in fungi by others. We characterized these Cyclase Opsins (Cyclops) in-vivo and in-vitro and determined tight light-regulation of cyclase activity. Expression of Cyclop in C. elegans yields fast light-activated cGMP production and allows reversible, non-invasive light manipulation of behaviour (6). The combination (coexpression or fusion) of light activated nucleotidyl cyclases and cyclic nucleotide-gated cation channels is an alternative approach to yield strong light-gated membrane conductance (6, 7).
References:
1: Nagel et al., (2002) Science 296: 2395-2398
2: Nagel et al., (2003) Proc Natl Acad Sci U.S.A. 100:13940-13945
3: Nagel et al., (2005) Current Biology 15(24):2279-84.
4: Zhang, ...Nagel, Gottschalk, Deisseroth (2007) Nature 446:633-639
5: Dawydow...Nagel*, Kittel*, (2013) PNAS 111(38):13972-7 (* corresp. authors)
6: Gao, ... Nagel*, Gottschalk* A. (2015) Nat Commun. 6:8046 (* corresp. authors)
7: Schröder-Lang, ...Nagel (2007) Nat Methods 4(1):39-42
