title: Cleavage of nucleolin and argyrophilic nucleolar organizer region associated proteins in apoptosis-induced cells.
abstract: To investigate the behavior of nuclear proteins in apoptotic cells, we examined the changes in nucleolin and proteins of the nucleolar organizing region during apoptosis in human osteoblastic cell lines, Saos-2 and MG63. Apoptosis was induced by treatment of these cells with okadaic acid. Proteins prepared from apoptotic cells were subjected to Western blot analysis and a modified Western blot method using silver nitrate. The anti-nucleolin antibody recognized the 110-kDa band and the staining intensity of this band decreased in the proteins prepared from the okadaic acid-treated apoptotic cells. The additional band of an 80-kDa was also detected in the proteins prepared from the apoptotic cells. Two major silver nitrate-stained bands, 110-kDa and 37-kDa, were detected among the proteins obtained from control cells. Like the Western blot analysis, the intensity of the 110-kDa silver nitrate-staining band decreased; an 80-kDa band appeared and its staining intensity increased in the lysate from the okadaic acid-treated cells. The signal intensity of the 37-kDa protein did not change in the sample from the apoptotic cells. In a cell-free apoptotic system, the 80-kDa protein was also detected and the amount of the 110-kDa protein decreased in the extract of Saos-2 cell nuclei incubated with apoptotic cytosol. The change in nucleolin in Saos-2 cells induced to undergo apoptosis was examined by an immunocytochemical procedure using the anti-nucleolin antibody and Hoechst 33342. Nucleolin was visible as dots in nucleoli in the control cells; however, it was not detected in the cells undergoing apoptosis. The dual-exposure view of Hoechst 33342 and anti-nucleolin staining cells confirmed that nucleolin had disappeared from the apoptotic nuclei of Saos-2.
authors.affiliation: Department of Histology and Oral Histology, Kyushu Dental College, Kitakyushu, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kito
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Shimizu
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Okamura
authors.forename: Kaya
authors.initials: K
authors.lastname: Yoshida
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Morimoto
authors.forename: Michi
authors.initials: M
authors.lastname: Fujita
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohba
authors.forename: Tatsuji
authors.initials: T
authors.lastname: Haneji
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western / Q000379:methods; D002458:Cell Fractionation; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002474:Cell-Free System; D053938:DNA Fragmentation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D009687:Nuclear Proteins / Q000378:metabolism*; D009697:Nucleolus Organizer Region / Q000737:chemistry / Q000378:metabolism*; D019319:Okadaic Acid / Q000494:pharmacology; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012835:Silver Nitrate / Q000378:metabolism*; D000097796:Nucleolin
chemical_list: D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D009687:Nuclear Proteins; D019319:Okadaic Acid; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D012835:Silver Nitrate; D000097796:Nucleolin