title: Induction of ubiquitin conjugating enzyme activity for degradation of topoisomerase II alpha during adenovirus E1A-induced apoptosis.
abstract: Topoisomerase (topo) II alpha is degraded via polyubiquitination during adenovirus E1A-induced apoptosis in MA1 cells, a derivative of the human epidermoid carcinoma cell line KB. Topo II alpha ubiquitination activity in MA1 cells increased nearly 10-fold after induction of E1A in response to dexamethasone. To identify a topo II alpha ubiquitination factor(s), the S100 fractions prepared from apoptosis-induced (42 h) and uninduced (0 h) MA1 cells were first fractionated by ubiquitin-Sepharose columns. The ubiquitination activity induced by E1A was predominantly eluted with 20 mM AMP. Further fractionation of the AMP eluates on Resource-Q columns and the thiolester formation of the proteins resolved by electrophoresis with biotinylated ubiquitin revealed that a species of E2 isozyme recovered in the QFT2 fraction increased markedly in MA1 cells after E1A expression. These results indicate that a ubiquitination factor(s) specific to topo II alpha is induced during E1A-induced apoptosis in MA1 cells.
authors.affiliation: Department of Biological Science and Technology, Science University of Tokyo, Noda, Japan. nakajima@rs.noda.sut.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: M
authors.initials: M
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Kuroda
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: A
authors.initials: A
authors.lastname: Kikuchi
authors.forename: H
authors.initials: H
authors.lastname: Seino
authors.forename: F
authors.initials: F
authors.lastname: Yamao
authors.forename: K
authors.initials: K
authors.lastname: Oda
mesh_terms: D017500:Adenovirus E1A Proteins / Q000096:biosynthesis / Q000494:pharmacology*; D000951:Antigens, Neoplasm; D017209:Apoptosis / Q000187:drug effects*; D002846:Chromatography, Affinity; D004250:DNA Topoisomerases, Type II / Q000302:isolation & purification / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007624:KB Cells; D008025:Ligases / Q000096:biosynthesis* / Q000302:isolation & purification; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: D017500:Adenovirus E1A Proteins; D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D007527:Isoenzymes; D014452:Ubiquitins; D044763:Ubiquitin-Conjugating Enzymes; D004250:DNA Topoisomerases, Type II; D008025:Ligases