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The COP9 Signalosome Interacts Physically with SCF COI1 and Modulates Jasmonate Responses

2003; Oxford University Press; Volume: 15; Issue: 5 Linguagem: Inglês

10.1105/tpc.010207

1532-298X

Suhua Feng, Ligeng Ma, Xiping Wang, Daoxin Xie, Savithramma P. Dinesh-Kumar, Ning Wei, Xing Wang Deng,

Plant biochemistry and biosynthesis

The COP9 signalosome (CSN) is an evolutionarily conserved, nucleus-enriched multiprotein complex. CSN plays roles in photomorphogenesis, auxin response, and floral organ formation, possibly via the regulation of ubiquitin-proteasome–mediated protein degradation. COI1 encodes an F-box protein, which is a subunit of SCFCOI1 E3 ubiquitin ligase, and is required for jasmonate (JA) responses. Here, we demonstrate using coimmunoprecipitation and gel-filtration analyses that endogenous as well as epitope-tagged COI1 forms SCFCOI1 and associates directly with CSN in vivo. Like the coi1-1 mutant, CSN reduction-of-function plants exhibited a JA-insensitive root elongation phenotype and an absence of JA-induced–specific gene expression. Genome expression profile analyses indicated that JA-triggered genome expression is critically dependent on COI1 dosage. More importantly, most of the COI1-dependent JA-responsive genes also required CSN function, and CSN abundance was shown to be important for JA responses. Furthermore, we showed that both COI1 and CSN are essential for modulating the expression of genes in most cellular pathways responsive to JA. Thus, CSN and SCFCOI1 work together to control genome expression and promote JA responses.