New fluorescent markers developed by US researchers have been used to visualise the four phases of the cell cycle in unprecedented detail. Using the new system, cells can be stained a different colour during each stage of division. This can reveal essential information about how the cells grow and reproduce.

A multidisciplinary team led by Michael Lin at the University of Stanford developed a system called Fucci4, a set of four orthogonal fluorescent indicators that can resolve all cell cycle phases.

During the first growth phase (G1), cells emit a bright yellow colour. Later, during DNA replication (also known as S phase) they gradually become cyan. Then comes G2 – a second growth phase, during which cells start turning fluorescent green. Finally, during cell division or mitosis, the two daughter cells flash pink under the microscope.

Researchers believe Fucci4 may have many applications in the study of diseases such as cancer, and that it will also come handy to investigate how certain drugs affect the different phases of the cell cycle.