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Updated: Aug 5, 2026

A Yeast 2-Hybrid Screen in Batch to Compare Protein Interactions
Published on: June 6, 2018
JAB1/CSN5 interacts with the GAL4 DNA binding domain: a note of caution about two-hybrid interactions
O Nordgård1, Ø Dahle, T Ø Andersen
1Department of Biochemistry, University of Oslo, P.O. Box 1041 Blindern, 0316 Oslo, Norway.
Abstract:
The Jun activation domain binding protein 1 (JAB1) was first identified as an interaction partner and coactivator of c-Jun. Subsequently, it was found to be a subunit of the COP9 signalosome (CSN) and termed CSN subunit 5 (CSN5). This complex regulates light-mediated development in plants and plays an essential role in a variety of organisms. A striking feature of JAB1/CSN5 is its reported interaction with a wide range of proteins and its modulation of their activity or stability. We applied the yeast two-hybrid system to screen for proteins interacting with the DNA-binding domain of the transcription factor c-Myb and found JAB1/CSN5 among the double-positive clones. To our surprise JAB1/CSN5 was shown to interact with the DNA-binding domain of GAL4 alone and had to be rejected as a false positive in the GAL4-based two-hybrid system. This finding emphasizes the necessity of particular caution when JAB1/CSN5 is found in two-hybrid screenings.
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