ZP8, a neuronal zinc sensor with improved dynamic range; imaging zinc in hippocampal slices with two-photon microscopy.
The synthesis of a difluorofluorescein monocarboxaldehyde platform and its use for preparing ZP8, a new member of the Zinpyr family of neuronal Zn(2+) sensors, are described. By combining an aniline photoinduced electron transfer (PET) switch and an electron-withdrawing fluorescein scaffold, ZP8 displays reduced background fluorescence and improved dynamic range compared to previous ZP probes. The bright sensor undergoes an 11-fold increase in fluorescence intensity upon Zn(2+) complexation (Phi = 0.03-0.35) with high selectivity over cellular concentrations of Ca(2+) and Mg(2+). In addition, sensors in the ZP family have been utilized for optical imaging in biological samples using two-photon microscopy (TPM). The cell-permeable ZP3 probe is capable of identifying natural pools of labile Zn(2+) within the mossy fiber synapses of live hippocampal slices using TPM, establishing the application of this technique for monitoring endogenous Zn(2+) stores.
Chang
Christopher J
CJ
Department of Chemistry, Picower Center for Learning and Memory, RIKEN-MIT Neuroscience Research Center, and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nolan
Elizabeth M
EM
Jaworski
Jacek
J
Okamoto
Ken-ichi
K
Hayashi
Yasunori
Y
Sheng
Morgan
M
Lippard
Stephen J
SJ
D000818:Animals; D005452:Fluoresceins / Q000138:chemical synthesis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry; D005464:Fluorobenzenes / Q000138:chemical synthesis* / Q000737:chemistry; D006624:Hippocampus / Q000737:chemistry*; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton; D009474:Neurons / Q000737:chemistry; D015032:Zinc / Q000032:analysis*
D005452:Fluoresceins; D005456:Fluorescent Dyes; D005464:Fluorobenzenes; C493738:ZP8 compound; D015032:Zinc