Circular permutated red fluorescent proteins and calcium ion indicators based on mCherry

Abstract

Red fluorescent indicators for calcium ion (Ca) are preferable, relative to blue-shifted alternatives, for biological imaging applications due to the lower phototoxicity, lower autofluorescent background and deeper tissue penetration associated with longer wavelength light. Accordingly, we undertook the development of a genetically encoded Ca indicator based on the popular and widely utilized Discosoma-derived red fluorescent protein, mCherry.