Mapping Neural Circuits with Activity-Dependent Nuclear Import of a Transcription Factor

Abstract

Abstract: Nuclear factor of activated T cells (NFAT) is a calcium-responsive transcription factor. We describe here an NFAT-based neural tracing method—CaLexA (calcium-dependent nuclear import of LexA)—for labeling active neurons in behaving animals. In this system, sustained neural activity induces nuclear import of the chimeric transcription factor LexA-VP16-NFAT, which in turn drives green fluorescent protein (GFP) reporter expression only in active neurons. We tested this system in Drosophila and found that volatile sex pheromones excite specific neurons in the olfactory circuit. Furthermore, complex courtship behavior associated with multi-modal sensory inputs activated neurons in the ventral nerve cord. This method harnessing the mechanism of activity-dependent nuclear import of a transcription factor can be used to identify active neurons in specific neuronal population in behaving animals.

Keywords::

• Drosophila
• olfaction
• antennal lobe
• pheromone
• NFAT
• activity dependent
• N2A
• immediate-early gene

ACKNOWLEDGMENTS

This work was partially supported by grants from the National Institute of Deafness and other Communication Disorders to J.W.W. (R01DCD009597, R21DC010458). K.M. was supported by a fellowship from the Japan Society for the Promotion of Science. We would like to thank Kristin Baldwin, Susy Kim, Chi-Hon Lee, and Cory Root for comments on the manuscript. We thank Gerald Crabtree for the NFATc1 plasmid and Allan Wong for the CD8-GFP-2A-CD8-GFP plasmid. J.W.W. thanks Kang Shen for helpful discussions.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.