Observing the dynamics of a specific chromosome locus in living cells can provide important information as to the molecular mechanisms underlying events such as chromosome segregation, homol-ogous chromosome pairing, chromosome arrangement, and gene expression. The lacO/LacI-GFP system provides a simple and useful method in which a chromosome locus is visualized by inserting lacO repeat arrays and then expressing an LacI–GFP fusion that specifically binds to the lacO sequence. This system has been adapted for use in Schizosaccharomyces pombe by expressing the LacI–GFP under a promoter of the dis1+ gene. Furthermore, a two-step integration method has been developed that ensures high-efficiency integration of lacO arrays to a desired target position.