Fig. 1: Development of a system for secretory GFP reconstitution labeling of neighboring cells.

a Schematic of sGRAPHIC strategy for GFP labeling of metastatic niche cells. C-terminal GFP fragments are secreted from sC-GR expressing cells. The secreted C-terminal GFP fragments are reconstituted with N-terminal GFP fragments displayed on the plasma membrane of N-GR expressing cells. b sGRAPHIC labeling in HEK293T cells. sGRAPHIC specifically labeled N-GR expressing HEK293T cells (red nuclei) neighboring on sC-GR expressing HEK293T cells (blue nuclei). The white-rectangle area is enlarged in the right panel. Similar results were observed in multiple fields of view in independent duplicate experiments. Scale bars indicate 50 µm. c Flow cytometry analysis of sGRAPHIC labeling. HEK293T/N-GR cells and HEK293T/sC-GR cells were co-cultured in equal numbers for 6 or 24 h, and the GFP intensity of mCherry-positive cells was measured. Similar results were observed in independent triplicate experiments. Source data are provided as a Source Data file. d Flow cytometry analysis of Cherry-niche labeling. The same number of HEK293T/Cherry-niche cells and HEK293T/H2B-Azurite cells were co-cultured for 6 or 24 h, and the mCherry intensity of Azurite-positive cells was measured. Similar results were observed in independent triplicate experiments. Source data are provided as a Source Data file. e Labeling efficiency of sGRAPHIC and Cherry-niche in flow cytometry measurements. Data were statistically analyzed with two-tailed Student’s t-test (n = 3 biologically independent samples). The p-values are indicated in the graph. Data are presented as mean values ± SEM. Source data are provided as a Source Data file.