title: CSN6, a subunit of the COP9 signalosome, is involved in early response to iron deficiency in Oryza sativa.
abstract: The COP9 signalosome (CSN) plays an important role in proteasome-mediated degradation by regulating CUL1 rubylation of the SCF ligase and is involved in many crucial biological processes. Here, we demonstrate a link between IDEF1 accumulation and the decline in COP9 derubylation activity in response to iron deficiency (-Fe) in rice (Oryza sativa). CSN6 expression is rapidly down-regulated during Fe depletion, contributing to reduced CSN activity, as judged by CSN5 and CUL1 expression, indicating CSN6 is involved in the early stage response of -Fe. In contrast to CSN6, the IDEF1 protein and expression of several iron uptake/utilisation-related genes are increased in response to -Fe. Thus, we constructed CSN6 transgenic sense and antisense lines and found that experimental depletion of CSN6 results in accumulation of the IDEF1 protein and up-regulation of several iron uptake/utilisation-related genes. Furthermore, IDEF1 can be decorated with K48-linked polyubiquitin and degraded via the 26S proteasome. Accumulated IDEF1 in antisense lines led to increased chlorophyll and Fe content in seedlings during -Fe. Collectively, the cellular CSN6 level is decreased during early stages of -Fe to ensure the rapid accumulation of IDEF1, which in turn up-regulates several iron uptake/utilisation-related genes to help overcome -Fe stress in rice.
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Song
authors.initials: S
authors.lastname: Tan
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Xiao-Xi
authors.initials: XX
authors.lastname: Pan
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Yue-Peng
authors.initials: YP
authors.lastname: Zang
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Jin
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Wei-Xi
authors.initials: WX
authors.lastname: Zu
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Xiao-Ting
authors.initials: XT
authors.lastname: Qi
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.|Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: College of Life Science, Capital Normal University, Beijing 100048, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Yin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics* / Q000378:metabolism; D000075686:COP9 Signalosome Complex / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D044842:Cullin Proteins / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D007501:Iron / Q000378:metabolism*; D000090463:Iron Deficiencies; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D044842:Cullin Proteins; D046912:Multiprotein Complexes; D007501:Iron; D000075686:COP9 Signalosome Complex; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease