title: Reduction in RNA synthesis following red cell-mediated microinjection of antibodies to RNA polymerase I.
abstract: Antibody molecules directed against RNA polymerase I, the enzyme responsible for rRNA synthesis, were introduced into rat hepatoma cells by red cell-mediated microinjection. Access of the antibodies to the nucleolus, the site of rRNA synthesis, was facilitated by microinjecting mitotic cells. Using indirect immunofluorescence, anti-RNA polymerase I immunoglobulins, but not control immunoglobulins, were found localized in the nucleoli of microinjected cells. To assess whether intracellular antibodies could alter RNA synthesis, cultures were labeled with [3H] uridine at various times after microinjection. Reduction in RNA synthesis, relative to cells microinjected with non-immune immunoglobulins, was observed within three hours. These results demonstrate that antibodies introduced into the cytoplasm of mitotic cells via red cell-mediated microinjection have free access to nuclear components and that they remain functional within the nuclei of living cells.
authors.forename: R A
authors.initials: RA
authors.lastname: Schlegel
authors.forename: L S
authors.initials: LS
authors.lastname: Miller
authors.forename: K M
authors.initials: KM
authors.lastname: Rose
mesh_terms: D000818:Animals; D000906:Antibodies / Q000008:administration & dosage; D000937:Antigen-Antibody Reactions; D006528:Carcinoma, Hepatocellular; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000201:enzymology; D002478:Cells, Cultured; D004912:Erythrocytes; D008113:Liver Neoplasms; D008845:Microinjections; D012313:RNA / Q000096:biosynthesis*; D012318:RNA Polymerase I / Q000037:antagonists & inhibitors* / Q000276:immunology; D051381:Rats
chemical_list: D000906:Antibodies; D012313:RNA; D012318:RNA Polymerase I