title: COP9 signalosome subunits 4 and 5 regulate multiple pleiotropic pathways in Drosophila melanogaster.
abstract: The COP9 signalosome (CSN) is an essential eight-subunit repressor of light-regulated development in Arabidopsis. This complex has also been identified in animals, though its developmental role remains obscure. CSN subunits have been implicated in various cellular processes, suggesting a possible role for the CSN as an integrator of multiple signaling pathways. In order to elucidate the function of the CSN in animals, a Drosophila model system has previously been established. Gel-filtration analysis with antibodies against CSN subunits 4, 5 and 7 revealed that these proteins act as a complex in Drosophila that is similar in size to the plant and mammalian complexes. Null mutations in either one of two subunits, CSN4 or CSN5, are larval lethal. Successful embryogenesis appears to be a consequence of maternal contribution of the complex. Biochemical analysis indicates that the different subunits are found in both CSN-dependent and CSN-independent forms, and that these forms are differentially affected by the mutations. Phenotypic characterization of these two mutants indicates that they show both shared and unique phenotypes, which suggest specific roles for each subunit. Both mutants have defective oocyte and embryo patterning, and defects in response to DNA damage, while csn5 mutants develop melanotic tumors and csn4 mutants have phenotypes reminiscent of defects in ecdysone signaling.
authors.affiliation: Department of Plant Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Efrat
authors.initials: E
authors.lastname: Oron
authors.forename: Mattias
authors.initials: M
authors.lastname: Mannervik
authors.forename: Sigal
authors.initials: S
authors.lastname: Rencus
authors.forename: Orit
authors.initials: O
authors.lastname: Harari-Steinberg
authors.forename: Shira
authors.initials: S
authors.lastname: Neuman-Silberberg
authors.forename: Daniel
authors.initials: D
authors.lastname: Segal
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Chamovitz
mesh_terms: D000818:Animals; D019521:Body Patterning; D000075686:COP9 Signalosome Complex; D016764:Cell Polarity; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D007814:Larva; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D046912:Multiprotein Complexes; D016296:Mutagenesis; D009865:Oocytes; D009866:Oogenesis; D010447:Peptide Hydrolases; D010641:Phenotype; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029721:Drosophila Proteins; D046912:Multiprotein Complexes; D011506:Proteins; D012097:Repressor Proteins; D008741:Methyl Methanesulfonate; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex