ABSTRACT
Oxygen concentrations vary between tissues of multicellular organisms and change under certain physiological or pathological conditions. Multiple methods have been developed for measuring oxygenation of biological samples in vitro and in vivo. However, most require complex equipment, are laborious and have significant limitations. Here we report that oxygen concentration determines the choice between two maturation pathways of DsRed FT (Timer). At high oxygen levels, this DsRed derivate matures predominantly into a red fluorescent isoform. By contrast, a green fluorescent isoform is favored by low oxygen levels. Ratiometric analysis of green and red fluorescence after a pulse of Timer expression in Drosophila larvae provides a record of the history of tissue oxygenation during a subsequent chase period, for the whole animal with single-cell precision. Tissue spreads revealed fine differences in oxygen exposure among different cells of the same organ. We expect that the simplicity and robustness of our approach will greatly impact hypoxia research, especially in small animal models.
Footnotes
Author contributions
Conceptualization: P.V.L., K.A.L., C.F.L.; Methodology: P.V.L.; Software: P.V.L.; Investigation: P.V.L., K.A.L., T.M., B.H., A.S.M.; Writing - original draft: P.V.L.; Writing - review & editing: P.V.L., K.A.L., C.F.L.; Visualization: P.V.L.; Supervision: P.V.L., C.F.L.; Funding acquisition: P.V.L., K.A.L., C.F.L.
Funding
This work was supported by grants from the Swiss National Science Foundation (Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung) to C.F.L. (grant number 31003A_152667) and National Institutes of Health grants R01 AI36178, R01 AI40085 and P01 AI091575. Imaging has been partially performed with IGB RAS equipment supported by the Ministry of Education and Science of the Russian Federation (grant number 16.552.11.7067). In vitro protein characterization was supported by the Russian Science Foundation (project 14-25-00129). Experiments were partially carried out using equipment provided by the IBCH core facility (CKP IBCH, supported by the Ministry of Education and Science of the Russian Federation, grant RFMEFI62117X0018). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. Deposited in PMC for release after 12 months.
