Genetically encodable calcium ion (Ca²⁺) indicators (GECIs) based on green fluorescent proteins (GFP) are powerful tools for imaging of cell signaling and neural activity in model organisms. Following almost 2 decades of steady improvements in the Aequorea victoria GFP-based GCaMP series of GECIs, the performance of the most recent generation (i.e., jGCaMP7) may have reached its practical limit due to the inherent properties of GFP. In an effort to sustain the steady progression toward ever-improved GECIs, we undertook the development of a new GECI based on the bright monomeric GFP, mNeonGreen (mNG). The resulting indicator, mNG-GECO1, is 60% brighter than GCaMP6s in vitro and provides comparable performance as demonstrated by imaging Ca²⁺ dynamics in cultured cells, primary neurons, and in vivo in larval zebrafish. These results suggest that mNG-GECO1 is a promising next-generation GECI that could inherit the mantle of GCaMP and allow the steady improvement of GECIs to continue for generations to come.

中文翻译：

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基于mNeonGreen荧光蛋白的明亮，高性能遗传编码的Ca2 +指示剂。

基于绿色荧光蛋白（GFP）的可遗传编码的钙离子（Ca ²⁺）指示剂（GECI）是用于对模型生物中的细胞信号传导和神经活动进行成像的强大工具。在基于维多利亚equequora GFP的GCaMP系列GECI进行了近二十年的稳步改进之后，由于GFP的固有特性，最新一代的性能（即jGCaMP7）可能已达到其实际极限。为了维持向不断改进的GECI的稳定发展，我们进行了基于明亮单体GFP mNeonGreen（mNG）的新GECI的开发。生成的指示剂mNG-GECO1在体外比GCaMP6s亮60％，并且具有可比的Ca ²⁺成像性能幼虫斑马鱼培养细胞，原代神经元和体内动力学的变化。这些结果表明，mNG-GECO1是有前途的下一代GECI，它可以继承GCaMP的理念，并使GECI的稳步提高持续到后代。