Department of Chemistry, University of California, Santa Barbara, CA 93106-5080, USA.
Biomolecular Science and Engineering Graduate Program, University of California, Santa Barbara, CA 93106-5080, USA.
J Magn Reson. 2024 Aug;365:107743. doi: 10.1016/j.jmr.2024.107743. Epub 2024 Jul 18.
Genetically encoded reporters for magnetic resonance imaging (MRI) offer a valuable technology for making molecular-scale measurements of biological processes within living organisms with high anatomical resolution and whole-organ coverage without relying on ionizing radiation. However, most MRI reporters rely on synthetic contrast agents, typically paramagnetic metals and metal complexes, which often need to be supplemented exogenously to create optimal contrast. To eliminate the need for synthetic contrast agents, we previously introduced aquaporin-1, a mammalian water channel, as a new reporter gene for the fully autonomous detection of genetically labeled cells using diffusion-weighted MRI. In this study, we aimed to expand the toolbox of diffusion-based genetic reporters by modulating aquaporin membrane trafficking and harnessing the evolutionary diversity of water channels across species. We identified a number of new water channels that functioned as diffusion-weighted reporter genes. In addition, we show that loss-of-function variants of yeast and human aquaporins can be leveraged to design first-in-class diffusion-based sensors for detecting the activity of a model protease within living cells.
用于磁共振成像 (MRI) 的基因编码报告器为在具有高解剖分辨率和整个器官覆盖的活体生物中进行分子级生物过程测量提供了有价值的技术，而无需依赖电离辐射。然而，大多数 MRI 报告器依赖于合成对比剂，通常是顺磁金属和金属配合物，这通常需要外源性补充以产生最佳对比。为了消除对合成对比剂的需求，我们之前引入了水通道蛋白-1（一种哺乳动物水通道），作为一种新的报告基因，用于使用扩散加权 MRI 对基因标记细胞进行完全自主检测。在这项研究中，我们旨在通过调节水通道蛋白的膜运输并利用跨物种水通道的进化多样性来扩展基于扩散的遗传报告器工具包。我们确定了一些新的水通道蛋白，它们可以作为扩散加权报告基因发挥作用。此外，我们还表明，酵母和人类水通道蛋白的功能丧失变体可用于设计基于扩散的首创传感器，用于检测活细胞内模型蛋白酶的活性。
