Patent ID: 7655434

Claim:
A method of monitoring a cell-cycle phase of a mammalian cell, the method comprising: culturing a mammalian cell comprising a mitosis biosensor polypeptide (MBP) comprising a plasma membrane targeting domain, a nuclear localization signal and a fluorescent label, a G1 phase biosensor polypeptide (G1BP) comprising a fluorescent label, and a S phase biosensor polypeptide (SBP) comprising a fluorescent label, under conditions suitable for proliferation of the mammalian cell, wherein each of the fluorescent labels of the G1BP, SBP, and MBP emit different fluorescence emission spectra; and detecting a MBP fluorescence pattern and at least one of a) G1BP fluorescence pattern established by a nuclear localized fluorescence and a cytoplasmic localized fluorescence; and b) SBP fluorescence pattern established by formation of fluorescence puncta in a nuclear region of the mammalian cell and disappearance of fluorescence, wherein nuclear envelope breakdown (NEB) is characterized by MBP fluorescence localized to a plasma membrane, indicating a mitosis phase of the cell cycle, and nuclear envelope reformation (NER) is characterized by MBP fluorescence localized to a nucleus, indicating interphase of the cell cycle.