Nuclear uptake of monoclonal antibody to a surface glycoprotein and its effect on transcription.
Nuclear transport and chromatin binding of monoclonal antibody (MAb) ME491, directed against a cell surface glycoprotein, was tested in intact cells and in a cell-free system. After a 24-h incubation with 125I-MAb ME491, the chromatin of melanoma cells and of colorectal carcinoma cells contained approximately 10 and 20%, respectively, of the antibody in nondegraded form. 125I-MAb ME491 was bound to a 55-kDa chromatin protein and localized in two HincII-digested chromatin fragments. Taken up by the nucleus, MAb ME491 inhibited transcription of ribosomal RNA genes by 70%. Nuclear uptake of 125I-MAb ME491 was increased up to ninefold when cells were preincubated with puromycin or actinomycin D. Nuclear uptake of MAb ME491 in a cell-free system was inhibited by ME491 antigen newly synthesized in the cytoplasm. Binding of 125I-MAb ME491 to the newly synthesized ME491 antigen caused precipitation of polysome-bound ME491 mRNA. The effect of MAb ME491 on transcription is discussed.
Rakowicz-Szulczynska
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EM
Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania 19104.
Koprowski
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D000911:Antibodies, Monoclonal / Q000032:analysis; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D001692:Biological Transport; D002467:Cell Nucleus / Q000276:immunology*; D002474:Cell-Free System; D002843:Chromatin / Q000276:immunology; D015179:Colorectal Neoplasms / Q000276:immunology; D003593:Cytoplasm / Q000276:immunology; D015245:Deoxyribonuclease BamHI; D015252:Deoxyribonucleases, Type II Site-Specific; D066246:ErbB Receptors / Q000276:immunology; D005455:Fluorescent Antibody Technique; D008545:Melanoma / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000032:analysis; D012335:RNA, Ribosomal / Q000235:genetics; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D002843:Chromatin; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D066246:ErbB Receptors; D015245:Deoxyribonuclease BamHI; D015252:Deoxyribonucleases, Type II Site-Specific; C024400:GTYRAC-specific type II deoxyribonucleases