Nucleic acid compositions encoding polypeptide products having at least two linked chromo/fluorescent domains, as well as the proteins encoded by the same, are provided. Also provided are the polypeptides encoded by the subject nucleic acids, as well as antibodies to the subject proteins and transgenic cells and organisms. The subject protein and nucleic acid compositions find use in a variety of different applications. Finally, kits for use in such applications, e.g., that include the subject nucleic acid compositions, are provided.