july, 2022
Event Details
Prof. Dr. Georg Nagel from the Institute of Physiology – Neurophysiology, University Würzburg will talk about “Light-sensitive Proteins from Microbes for non-invasive Light-manipulation of Animals and Plants”
Abstract
The discovery of Channelrhodopsins (ChR) and their characterization by heterologous expression in 2002/2003 paved the way to highly specific light-manipulation of cells or animals, a technique now called optogenetics. More channelrhodopsins from different organisms were found and genetic engineering generated a further variety so that many different optogenetic tools are available now. Light-activated ion pumps (microbial rhodopsins, like ChR) further expanded the optogenetic toolbox. Already in 2007 we established that also a microbial flavoprotein, a photo-activated adenylyl cyclase (PAC), is a useful tool to increase cAMP in animal cells or live Drosophila flies, simply by blue light illumination. By genetic engineering we further improved a PAC to a membrane-bound adenylyl cyclase with no activity under red light or in the dark. Similar improvements could be demonstrated for a natural soluble PAC.
In many animal cells the necessary cofactor for rhodopsins – i.e. retinal (Vitamin A) – is already present or may be easily provided by feeding which is not the case in land plants. To enable “green optogenetics” with rhodopsins we first established growth under non-activating red light and generated transgene tobacco plants which produced endogenous retinal. After several rounds of modification, microbial rhodopsins could then be functionally expressed in the plasma membrane of different plant cells. Light-activation of these rhodopsins now enables novel approaches to study plant cellular signalling.
Chairs: Tobias Moser and Thomas Mager
Poster of the talk: 
