title: Regulation of gene expression of proteasomes (multi-protease complexes) during growth and differentiation of human hematopoietic cells.
abstract: We have reported that proteasomes are expressed at abnormally high levels in various hematopoietic tumor cells (Kumatori, A., Tanaka, K., Inamura, N., Sone, S., Ogura, T., Matsumoto, T., Tachikawa, T., Shin, S., and Ichihara, A. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 7071-7075). In the present study, we examined changes in the expressions of proteasomes during growth of peripheral T-lymphocytes from healthy adults and differentiation of human leukemic cell lines. Up-regulation of mRNAs encoding multiple proteasome subunits was observed during proliferation of resting T-cells induced by mitogens such as phytohemagglutinin and interleukin-2. In contrast, in vitro terminal differentiation into monocytic, granulocytic, and erythroid cells of various immature leukemic cell lines, such as HL-60 promyelocytic leukemia cells and K562 erythroleukemia cells, by various inducing agents caused rapid and marked down-regulation of proteasomes expression, independently of the cell type, direction of differentiation, or type of signal. The syntheses of proteasome subunits of 21-31 kDa and their associated components of 35-110 kDa, measured by [35S]methionine incorporation, were much higher in mitogen-activated T-cells and unstimulated HL-60 cells, which grow rapidly, than in resting and differentiated cells, indicating apparent correlations of the mRNA levels of proteasomes with their translational activities. However, immunochemically, no detectable difference in the cellular contents of proteasomes was found in these cells in induced and uninduced states for proliferation and differentiation, suggesting accelerated turnover of proteasomes in rapidly proliferating cells. Inhibition of proteasome expression by an antisense oligodeoxynucleotide for the largest proteasome subunit, C2, caused partial arrest of cell cycle progression of T-lymphocytes, suggesting that up-regulation of proteasomes is indispensable for proliferation of the cells. We also observed that the nuclear fraction of proteasomes increased in proliferating T-cells and that proteasomes moved rapidly between the nucleus and cytoplasm during differentiation of HL-60 cells.
authors.affiliation: Biomaterial Research Institute, Yokohama, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Shimbara
authors.forename: E
authors.initials: E
authors.lastname: Orino
authors.forename: S
authors.initials: S
authors.lastname: Sone
authors.forename: T
authors.initials: T
authors.lastname: Ogura
authors.forename: M
authors.initials: M
authors.lastname: Takashina
authors.forename: M
authors.initials: M
authors.lastname: Shono
authors.forename: T
authors.initials: T
authors.lastname: Tamura
authors.forename: H
authors.initials: H
authors.lastname: Yasuda
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: A
authors.initials: A
authors.lastname: Ichihara
mesh_terms: D001483:Base Sequence; D001773:Blood Cells / Q000166:cytology* / Q000502:physiology; D015152:Blotting, Northern; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D002460:Cell Line; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007150:Immunohistochemistry; D007938:Leukemia; D015473:Leukemia, Promyelocytic, Acute; D046911:Macromolecular Substances; D008715:Methionine / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology; D009097:Multienzyme Complexes / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013462:Sulfur Radioisotopes; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D013462:Sulfur Radioisotopes; D008715:Methionine; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex