Many living things can respond to electric fields, either moving or using them to detect prey or enemies. Weak electric fields may be important growth and development, and in wound healing: it's known that one of the signals that guides cells into a wound to repair it is a disturbance in the normal electric field between tissues. This ability to move in response to an electric field is called galvanotaxis or electrotaxis.
UC Davis dermatology professor Min Zhao, Peter Devroetes at Johns Hopkins University and colleagues hope to unravel how these responses work, studying both body cells and Dictyostelium discoideum, an amoeba that lives in soil. Dictyostelium is unusual because it spends part of its life crawling around as a single-cell amoeba, but occasionally multiple amoebae will come together to form a fruiting body.
In a paper just published in the journal Science Signaling, Zhao and colleagues screened Dictyostelium for genes that affect electrotaxis. They used special barcoded microplates developed by Tingrui Pan, professor of biomedical engineering at UC Davis to screen hundreds of amoeba strains.
The team identified a number of genes, including one called PiaA, which encodes a critical component of a pathway controlling motility. Other genes associated with electrotaxis in Dictyostelium were also linked to the same pathway.
Right now, no one nows how cells detect these very weak electric fields, Zhao said. The screening technique could be used to identify more genes linked to electrotaxis and help researchers piece together exactly how electrical signals are detected and turned into action.
Coauthors on the paper include biologists, engineers and mathematicians. They are: at UC Davis, Runchi Gao, Siwei Zhao, Yaohui Sun, Sanjun Zhao, Jing Gao, and Alex Mogilner; Jane Borleis, Stacey Willard, Ming Tang, Huaqing Cai, and Yoichiro Kamimura at Johns Hopkins University; Yuesheng Huang, Jianxin Jiang, Xupin Jiangat the State Key Laboratory of Trauma, Burns and Combined Injury, Third Military Medical University, Chongqing, China; and Zunxi Huang, Yunnan Normal University, Kunming, China.
The work was supported by the National Science Foundation (U.S.), the California Institute for Regenerative Medicine, National Institutes of Health, the National Science Foundation of China and the Wellcome Trust.