Abstract
The COP9 signalosome (CSN), a nuclear protein complex essential for plant and animal development, regulates proteasome-mediated proteolysis. To characterize a novel intravital mechanism of CSN, CSN1 binding proteins were isolated and analyzed in the model plant Arabidopsis.
SAP130, one of the identified CSN1 binding proteins, is a component of the SF3b complex which is involved in mRNA splicing. In Arabidopsis, SAP130 was coded by two genes (AtSAP130a and AtSAP130b) which both map on chromosome 3. The mRNA for both genes were detected in all observed organs. The expression level of AtSAP130b was found to be significantly higher than that of AtSAP130a. Pull down experiments, in vitro, revealed that AtSAP130 directly bound AtCSN1 at the N terminal portion of the protein. Here we discuss the possible role of CSN function in post-transcriptional regulation in Arabidopsis.
