On December 10th, 2020, Professor Liu Jianfeng’s group from college of Life Science and Technology of Huazhong University of Science and Technology published a paper with the title of “Regulation of photosensation by hydrogen peroxide and antioxidants in C. elegans” online on the international well-known journal PLoS Genetics. This study revealed the regulation mechanism of photoreceptor LITE-1 in C.elegans. Zhang Wenyuan and He Feiteng, PhD students of college of life science and technology, are co-first authors. Professor Liu Jianfeng and Professor Shawn Xu from University of Michigan are co-corresponding authors, and Huazhong University of science and technology is the is the first institute contributing for this paper.

Link to the article: (https://doi.org/10.1371/journal.pgen.1009257).

Light sensation is a universal phenomenon found in most organisms. Animals living in dark environments without light-sensing organs are generally believed to have not evolved or to have lost sensitivity to light during evolution. Otherwise, there must be a mechanism(s) that acts to keep such animals in the dark. The eyeless model organism C. elegans exhibits robust phototaxis behavior in response to short-wavelength light, particularly UV light. Liu Lab found that C. elegans senses light through LITE-1, a unique photoreceptor protein that belongs to the invertebrate taste receptor family, this work published on Cell, 2016.

To figure out the mechanism of how LITE-1 regulate photosensation. Here, we performed a forward genetic screen, using light-induced contraction of LITE-1-expressing muscles (i.e. paralysis) as a readout to screen for genes that when mutated suppress LITE-1 function and got six candidates. One major group of lite-1 suppressors are the genes required for producing the two primary antioxidants thioredoxin and glutathione, suggesting that oxidization of LITE-1 inhibits its function. Indeed, the oxidant hydrogen peroxide (H₂O₂) suppresses phototaxis behavior and inhibits the photoresponse in photoreceptor neurons, whereas other sensory behaviors are relatively less vulnerable to H₂O₂. Conversely, antioxidants can rescue the phenotype of lite-1 suppressor mutants and promote the photoresponse. As UV light illumination generates H₂O₂, we propose that upon light activation of LITE-1, light-produced H₂O₂ then deactivates LITE-1 to terminate the photoresponse, while antioxidants may promote LITE-1’s recovery from its inactive state. Our studies provide a potential mechanism by which H₂O₂ and antioxidants act synergistically to regulate photosensation in C. elegans.