The identification of two newly discovered fluorescent proteins in human glioblastoma

Glioblastoma (GBM) is a common malignancy featured by an extremely strong proliferation with enriched genetic information. Due to the rapid proliferation and the unstable genome-induced evolutionary potential, unique proteins may be expressed in GBM cells under the certain influence of the microenvironment. We therefore speculated that fluorescent proteins exist in GBM cells. During the immunofluorescence staining assay, we accidently discovered autofluorescence in primary GBM cells without fluorescent labeling, which were further validated as 2 newly discovered fluorescent proteins excited by 467 nm and 378 nm wavelength, respectively, namely human fluorescent protein Ⅰ and Ⅱ (HFP1, HFP2). Fluorescence colocalization and fluorescence resonance energy transfer (FRET) results showed the tight interaction of HFP1 and HFP2, and their synergistic effect. Our results for the first time identified 2 newly discovered fluorescent proteins in GBM cells, and clarified their chemical properties.