Preprint: Long-Stokes-Shift mScarlet3 as a Structural Marker for Two-Photon Imaging

A transgenic fly harbouring LSSmScarlet3 that can be imaged alongside green GCaMP using a single 920 nm laser—dual-channel functional and structural two-photon imaging, with no second laser needed.

Excited to share our new preprint! 🎉

We made a transgenic fly harbouring a long-Stokes-shift red fluorescent protein (LSSmScarlet3) that can be imaged alongside green GCaMP using a single 920 nm laser. No second laser needed.

This will let researchers do dual-channel functional and structural two-photon imaging more simply and affordably than before. We show the spectral properties, validate it in live fly (Drosophila) brains, and demonstrate minimal crosstalk with the green channel. In addition, we think this tool could be useful well beyond structural marking in applications like from co-imaging synaptic activity to tracking subcellular localization and protein levels in real time.

The transgenic line is validated and ready to use, we hope it’s useful to the fly imaging community.

Preprint: https://doi.org/10.64898/2026.04.12.718060

Work by Sangyu Xu, Xianyuan Zhang, King Yee Cheung, Yishan Mai and others.