Water bears shine brightly via a novel in vivo expression vector system

Water bears, or tardigrades, are microscopic animals that can survive extreme conditions including exposure to the vacuum of space by entering an ametabolic state called anhydrobiosis. Despite the potential value to be gained by studying the mechanisms of anhydrobiosis, the lack of genetic tools has been a major challenge in the study of tardigrades.

Sae Tanaka and Kazuharu Arakawa who are both affiliated to the Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, and the Institute for Advanced Biosciences, Keio University (both located in Japan), have established a new in vivo expression system which they have named TardiVec. This system is based on a DNA vector with promoters originating from the anhydrobiotic tardigrade Ramazzottius varieornatus. It enables live imaging of the dynamics of proteins and cells in live tardigrades using fluorescent proteins such as GFP.

In this study, the researchers confirmed that TardiVec enables the expression of GFP and GCaMP, a calcium indicator, in tardigrade cells. The GFP fluorescence lasted for more than 10-days, and TardiVec can be applied to several species in the class Eutardigrada. In addition, they observed tissue-specific expression of anhydrobiosis-related genes in tardigrades. This suggests that even within a tardigrade, different tissues harbor specialized mechanisms to cope with drying.

This technology for tardigrades opens up new possibilities for studying anhydrobiosis and other mechanisms of stress tolerance. The researchers hope that TardiVec will facilitate further research using tardigrades as a model organism, unlocking the secrets of their ability to withstand extreme conditions, and potentially paving the way for new ways to enhance stress tolerance in other organisms.