We have developed a technique to test protein-protein interactions in plant. A yellow fluorescent protein (YFP) is split into two non-overlapping fragments. Each fragment is cloned in-frame to a gene of interest via Gateway system, enabling expression of fusion proteins. Reconstitution of YFP signal only occurs when the inquest proteins interact.
We have developed a BiFC technique to test the interaction between two proteins in vivo. This is accomplished by splitting a yellow fluorescent protein (YFP) into two non-overlapping fragments. Each fragment is cloned in-frame to a gene of interest. These constructs can then be co-transformed into Nicotiana benthamiana via Agrobacterium mediated transformation, allowing the transit expression of fusion proteins. The reconstitution of YFP signal only occurs when the inquest proteins interact 1-7. To test and validate the protein-protein interactions, BiFC can be used together with yeast two hybrid (Y2H) assay. This may detect indirect interactions which can be overlooked in the Y2H. Gateway technology is a universal platform that enables researchers to shuttle the gene of interest (GOI) into as many expression and functional analysis systems as possible8,9. Both the orientation and reading frame can be maintained without using restriction enzymes or ligation to make expression-ready clones. As a result, one can eliminate all the re-sequencing steps to ensure consistent results throughout the experiments. We have created a series of Gateway compatible BiFC and Y2H vectors which provide researchers with easy-to-use tools to perform both BiFC and Y2H assays10. Here, we demonstrate the ease of using our BiFC system to test protein-protein interactions in N. benthamiana plants.
BiFC assay is a powerful tool for studying protein interactions. Unlike the traditional Y2H assay, BiFC not only allows the visualization of protein-protein interactions, but also provides more information of the protein complex such as sub-cellular localization. Also, it is possible to detect indirect interactions as long as the two candidate proteins can be brought close enough by a third partner. Like any technology, BiFC has its limitations. Due to the requirement of molecular oxygen for fluorophore formation, BiFC …
The authors have nothing to disclose.
We thank Vi Nguyen for reading the manuscript and general lab assistance.
Name of the reagent | Company | Catalogue number |
Acetosyringone | Sigma | D134406 |
MES hydrate | Sigma | M2933 |
1 mL slip-tip tuberculin syringe | BD | 309602 |