Engineered Foreign Gene
- Previous Names
- [Em λ][Ex λ]
GCaMP is a genetically encoded calcium indicator, or GECI. GECIs are designed to show the calcium ion status of a tissue or medium and are either transfected into cell lines or via transgenic crosses. GCaMP is created from the M13 fragment of the chicken Mylk gene (which contains the target sequence for calmodulin binding), fused to the N terminus of a circularly permutated form of EGFP. The C terminus of cpEGFP is fused to the rat calmodulin gene (CaM). When Ca2+ binds to CaM, the interaction between Ca2+CaMM13 induces a conformational change in cpEGFP which causes a subsequent change in fluorescence intensity.
Amino acid substitutions in the cpEGFP region have led to improvements in signal-to-noise ration, faster kinetics and greater response. Versions of GCaMP include GCaMP1.6, GCaMPHS, GCaMP2 and GCaMP3.
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- 97 figures from 53 publications