New type of MRI reporter taps water channel protein to image genetic activity

Aquaporin is a natural protein that controls the flow of water molecules into and out of cells. When it is joined with a gene researchers want to study, the result is a reporter gene. If the gene is expressing - if it is active and “on” - aquaporin levels go up, increasing the movement of water molecules. Diffusion-weighted MRI is well-suited to mapping water activity and renders an image that is darker in areas of genetic activity.
The new method overcomes many of the limits and challenges of existing reporter genes and MRI techniques. For instance, unlike some metal-based procedures, water molecules are plentiful in all cells and don’t pose the potential for toxicity that metals do. Compared to other procedures, such as the chemical exchange saturation transfer (CEST) process, MR images based on water activity can be rendered using common parameters on standard MRI scanners commonly found in labs and clinics.

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