Injection of anti-topoisomerase I IgG into nuclei of mouse L929 cells leads to inhibition of transcription of exogenously introduced SV40 large T antigen gene.
Affinity-purified anti-topoisomerase I IgG was microinjected into nuclei of mouse L929 cells and the effect on transcription of cellular RNA and exogenous SV40 T antigen mRNA was investigated. Synthesis of stable cellular RNA synthesis as measured by [3H]-uridine incorporation followed by autoradiography was inhibited by about 50%. A plasmid containing the entire early region of SV40 genome was microinjected with the antibody, and messenger RNA for T antigen was measured by in situ hybridization. At 24 h after injection of the antibody the accumulation of the mRNA was reduced by about 60%, and at 48 h by about 50%. These results are consistent with the interpretation that topoisomerase I is essentially involved in the transcriptional process in active chromatin.
Matsumoto
K
K
Department of Patent Administration, Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan.
Sugawara
I
I
Takahashi
T
T
Andoh
T
T
D000818:Animals; D000957:Antigens, Viral, Tumor / Q000096:biosynthesis* / Q000235:genetics; D004264:DNA Topoisomerases, Type I / Q000276:immunology / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D007074:Immunoglobulin G; D017403:In Situ Hybridization; D007739:L Cells; D051379:Mice; D012333:RNA, Messenger / Q000096:biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis; D013539:Simian virus 40 / Q000235:genetics / Q000276:immunology; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D000957:Antigens, Viral, Tumor; D007074:Immunoglobulin G; D012333:RNA, Messenger; D012367:RNA, Viral; D004264:DNA Topoisomerases, Type I