Abstract
COP9 signalosome is a protein complex known to regulate ubiquitin-mediated protein degradation. Independent of this proteolysis, CSN subunit1 (CSN1) regulates signal transduction, possibly through transcriptional repression. In plants, the N-terminal half of CSN1 (CSN1N) is essential for survival. In order to reveal regulatory mechanism of CSN1N at the molecular level, we aim to systematically identify CSN1N-binding factors in plants. To date, general regulators on mRNA processing have been identified in mammals, while specific transcription factors have been identified in Arabidopsis. Systematic analysis on, CSN1-interacting factors should reveal the conservation and differentiation among the different kingdoms.
Here, we analyzed expression conditions of plant CSN1N in vitro, when fused to various tags. Flag-CSN1N gave best results for expression quantity and quality. We then subjected Flag-CSN1N to immuno-precipitation experiments against protein extracted from Arabidopsis. We will further discuss the details and results of this approach.
