Induction of ubiquitin conjugating enzyme activity for degradation of topoisomerase II alpha during adenovirus E1A-induced apoptosis.
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.
Nakajima
T
T
Department of Biological Science and Technology, Science University of Tokyo, Noda, Japan. nakajima@rs.noda.sut.ac.jp
Kimura
M
M
Kuroda
K
K
Tanaka
M
M
Kikuchi
A
A
Seino
H
H
Yamao
F
F
Oda
K
K
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*
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