title: Superoxide dismutases, SOD1 and SOD2, play a distinct role in the fat body during pupation in silkworm Bombyx mori.
abstract: One way that aerobic biological systems counteract the generation of reactive oxygen species (ROS) is with superoxide dismutase proteins SOD1 and SOD2 that metabolize superoxide radicals to molecular oxygen and hydrogen peroxide or scavenge oxygen radicals produced by the extensive oxidation-reduction and electron-transport reactions that occur in mitochondria. We characterized SOD1 and SOD2 of Bombyx mori isolated from the fat body of larvae. Immunological analysis demonstrated the presence of BmSOD1 and BmSOD2 in the silk gland, midgut, fat body, Malpighian tubules, testis and ovary from larvae to adults. We found that BmSOD2 had a unique expression pattern in the fat body through the fifth instar larval developmental stage. The anti-oxidative functions of BmSOD1 and BmSOD2 were assessed by exposing larvae to insecticide rotenone or vasodilator isosorbide dinitrate, which is an ROS generator in BmN4 cells; however, exposure to these compounds had no effect on the expression levels of either BmSOD protein. Next, we investigated the physiological role of BmSOD1 and BmSOD2 under environmental oxidative stress, applied through whole-body UV irradiation and assayed using quantitative RT-PCR, immunoblotting and microarray analysis. The mRNA expression level of both BmSOD1 and BmSOD2 was markedly increased but protein expression level was increased only slightly. To examine the differences in mRNA and protein level due to UV irradiation intensity, we performed microarray analysis. Gene set enrichment analysis revealed that genes in the insulin signaling pathway and PPAR signaling pathway were significantly up-regulated after 6 and 12 hours of UV irradiation. Taken together, the activities of BmSOD1 and BmSOD2 may be related to the response to UV irradiation stress in B. mori. These results suggest that BmSOD1 and BmSOD2 modulate environmental oxidative stress in the cell and have a specific role in fat body of B. mori during pupation.
authors.affiliation: Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan; Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Noshio, 2-522-1, Kiyose, Tokyo 204-8588, Japan.
authors.forename: Yosui
authors.initials: Y
authors.lastname: Nojima
authors.affiliation: Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ito
authors.affiliation: Database Center for Life Science (DBCLS), Research Organization of Information and Systems (ROIS), Yata 1111, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Ono
authors.affiliation: Database Center for Life Science (DBCLS), Research Organization of Information and Systems (ROIS), Yata 1111, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Takeru
authors.initials: T
authors.lastname: Nakazato
authors.affiliation: Database Center for Life Science (DBCLS), Research Organization of Information and Systems (ROIS), Yata 1111, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Bono
authors.affiliation: Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Sato
authors.affiliation: Insect Genome Research Unit, National Institute of Agrobiological Sciences, Tsukuba 305-8634, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Suetsugu
authors.affiliation: Insect Genome Research Unit, National Institute of Agrobiological Sciences, Tsukuba 305-8634, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Insect Genome Research Unit, National Institute of Agrobiological Sciences, Tsukuba 305-8634, Japan.
authors.forename: Kimiko
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Noshio, 2-522-1, Kiyose, Tokyo 204-8588, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Satoh
authors.affiliation: Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tabunoki
authors.affiliation: Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Fugo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005216:Fat Body / Q000378:metabolism*; D005786:Gene Expression Regulation; D007306:Insecticides / Q000494:pharmacology; D007548:Isosorbide Dinitrate / Q000494:pharmacology; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D017382:Reactive Oxygen Species / Q000378:metabolism; D012402:Rotenone / Q000494:pharmacology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D000072105:Superoxide Dismutase-1; D000099156:Superoxide Dismutase 2
chemical_list: D018076:DNA, Complementary; D007306:Insecticides; D007548:Isosorbide Dinitrate; D017382:Reactive Oxygen Species; D012402:Rotenone; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D000099156:Superoxide Dismutase 2