Functional fluorescent Ca2+ indicator proteins in transgenic mice under TET control

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Genetically encoded fluorescent calcium indicator proteins (FCIPs) are crucial for studying calcium dynamics in cellular processes.
• Calcium indicators derived from green fluorescent protein are vital for measuring neuronal population activity.
• Fast neuronal activity, characterized by millisecond calcium transients, requires sensitive detection methods.

Purpose of the Study:

• To produce stable transgenic mouse lines expressing two functional FCIPs: inverse pericam and camgaroo-2.
• To evaluate the efficacy of these FCIPs in detecting intracellular calcium concentration changes in response to neuronal activity.

Main Methods:

• Generation of transgenic mouse lines utilizing a tetracycline-inducible promoter for FCIP expression.
• In vitro and in vivo assays to measure FCIP fluorescence changes.
• Stimulation protocols including action potentials, synaptic, and sensory inputs.

Main Results:

• Stable transgenic mouse lines for inverse pericam and camgaroo-2 were successfully produced.
• Both FCIPs exhibited substantial and rapid fluorescence changes in response to stimuli known to increase intracellular calcium.
• Detected calcium transients correlate with neuronal activity, including action potentials and synaptic stimulation.

Conclusions:

• Inverse pericam and camgaroo-2 are effective genetically encoded fluorescent calcium indicators for monitoring neuronal activity.
• These FCIPs, expressed in transgenic mice, provide a valuable tool for studying fast calcium dynamics in the nervous system.
• The tetracycline-inducible system allows for controlled expression of FCIPs in specific neuronal populations.