[New type of two-hybrid systems in protein-protein interaction studies].

Some new type of two-hybrid systems, such as split-ubiquitin system, protein-fragment complementation assay, repressor reconstitution assay and SOS recruitment system, have been developed recently. Similar to the original transcription-based yeast two-hybrid system, these systems are to establish an assay for protein-protein interactions, in which some functional proteins can be split into two parts in structure and their activities can be recovered by reconstitution. Due to their non-transcriptional properties, these new types of two-hybrid systems have become useful extension of the yeast two-hybrid system and powerful tools for the study of protein interactions.